Technical Glossary

BioCRUDE Technologies, Inc. has prepared a glossary of terms for your reference. This Glossary of technical terms has been compiled from a number of sources and should not be considered and/or construed as an "Official" or "Detailed" glossary of technical environmental terms in the "Waste to Energy" milieu.

This glossary of technical terms has been categorized alphabetically, using the index to the right.

Abandoned Well: A well whose use has been permanently discontinued or which is in a state of such disrepair that it cannot be used for its intended purpose.

Abatement: Reducing the degree or intensity of, or eliminating, pollution.

Abatement Debris: Waste from remediation activities.

Absorbed Dose: In exposure assessment, the amount of a substance that penetrates an exposed organism's absorption barriers (e.g. skin, lung tissue, gastrointestinal tract) through physical or biological processes.

Absorptance: The ratio of the radiation absorbed by a surface to the total energy falling on that surface described as a percentage.

Absorption: The uptake of water, other fluids, or dissolved chemicals by a cell or an organism (as tree roots absorb dissolved nutrients in soil).

Absorption Barrier: Any of the exchange sites of the body that permit uptake of various substances at different rates (e.g. skin, lung tissue, and gastrointestinal-tract wall).

Access Charge: A charge paid by all market participants withdrawing energy from the ISO-controlled grid. The access charge will recover the portion of a utility's transmission revenue requirement not recovered through the variable usage charge.

Accident Site: The location of an unexpected occurrence, failure or loss, either at a plant or along a transportation route, resulting in a release of hazardous materials.

Acclimatization: The physiological and behavioral adjustments of an organism to changes in its environment.

Acid: A corrosive solution with a pH less than 7.

Acid Aerosol: Acidic liquid or solid particles small enough to become airborne. High concentrations can irritate the lungs and have been associated with respiratory diseases like asthma.

Acid Deposition: A complex chemical and atmospheric phenomenon that occurs when emissions of sulfur and nitrogen compounds and other substances are transformed by chemical processes in the atmosphere, often far from the original sources, and then deposited on earth in either wet or dry form. The wet forms, popularly called "acid rain," can fall to earth as rain, snow, or fog. The dry forms are acidic gasses or particulates.

Acid Mine Drainage: Drainage of water from areas that have been mined for coal or other mineral ores. The water has a low pH because of its contact with the sulfur-bearing material and is harmful to aquatic organisms.

Acid Neutralizing Capacity: Measure of the ability of a base (e.g. water or soil) to resist changes in pH.

Acidic: The condition of water or soil that contains a sufficient amount of acid substances to lower the pH below 7.0.

Action Levels: 1. Regulatory levels recommended by EPA for enforcement by FDA and USDA when pesticide residues occur in food or feed commodities for reasons other than the direct application of the pesticide. As opposed to "tolerances" which are established for residues occurring as a direct result of proper usage, action levels are set for inadvertent residues resulting from the previous legal use or accidental contamination. 2. In the Superfund program, the existence of a contaminant concentration in the environment high enough to warrant action or trigger a response under SARA and the National Oil and Hazardous Substances Contingency Plan. The term is also used in other regulatory programs.

Activated Carbon: A highly adsorbent form of carbon used to remove odors and toxic substances from liquid or gaseous emissions. In waste treatment, it is used to remove dissolved organic matter from waste drinking water. It is also used in motor vehicle evaporative control systems.

Activated Sludge: Product that results when primary effluent is mixed with bacteria-laden sludge and then agitated and aerated to promote biological treatment, speeding the breakdown of organic matter in raw sewage undergoing secondary waste treatment.

Activator: A chemical added to a pesticide to increase its activity.

Active Ingredient: In any pesticide product, the component that kills, or otherwise controls, target pests. Pesticides are regulated primarily on the basis of active ingredients.

Active Solar Energy: Solar radiation used by special equipment to provide space heating, hot water or electricity.

Active Solar Energy System: A system designed to convert solar radiation into usable energy for space, water heating, or other uses. It requires a mechanical device, usually a pump or fan, to collect the sun's energy.

Acute Effect: An adverse effect on any living organism which results in severe symptoms that develop rapidly; symptoms often subside after the exposure stops.

Acute Exposure: A single exposure to a toxic substance which may result in severe biological harm or death. Acute exposures are usually characterized as lasting no longer than a day, as compared to longer, continuing exposure over a period of time.

Acute Toxicity: The ability of a substance to cause severe biological harm or death soon after a single exposure or dose. Also, any poisonous effect resulting from a single short-term exposure to a toxic substance.

Adaptation: Changes in an organism's physiological structure or function or habits that allow it to survive in new surroundings.

Add-on Control Device: An air pollution control device such as carbon absorber or incinerator that reduces the pollution in an exhaust gas. The control device usually does not affect the process being controlled and thus is "add-on" technology, as opposed to a scheme to control pollution through altering the basic process itself.

Adequately Wet: Asbestos-containing material that is sufficiently mixed or penetrated with liquid to prevent the release of particulates.

Adjustment Bid: A bid that is used by the ISO to adjust supply or demand when congestion is anticipated.

Administered Dose: In exposure assessment, the amount of a substance given to a test subject (human or animal) to determine dose-response relationships. Since exposure to chemicals is usually inadvertent, this quantity is often called potential dose.

Adsorption: Removal of a pollutant from air or water by collecting the pollutant on the surface of a solid material; e.g., an advanced method of treating waste in which activated carbon removes organic matter from waste-water.

Adulterants: Chemical impurities or substances that by law do not belong in a food or pesticide.

Adulterated: 1. Any pesticide whose strength or purity falls below the quality stated on its label. 2. A food, feed, or product that contains illegal pesticide residues.

Advanced Conversion Technology: New and developing thermal processes, such as gasification and pyrolysis, which can be utilized to dispose of MSW.

Advanced Treatment: A level of wastewater treatment more stringent than secondary treatment; requires an 85-percent reduction in conventional pollutant concentration or a significant reduction in non-conventional pollutants.

Advanced Wastewater Treatment: Any treatment of sewage that goes beyond the secondary or biological water treatment stage and includes the removal of nutrients such as phosphorus and nitrogen and a high percentage of suspended solids.

Adverse Hydro: Water conditions limiting the production of hydroelectric power. In years having below-normal levels of rain and snow, and in seasons having less-than-usual runoff from mountain snow pack, there is then less water available for hydro energy production.

Aerated Lagoon: A holding and/or treatment pond that speeds up the natural process of biological decomposition of organic waste by stimulating the growth and activity of bacteria that degrade organic waste.

Aeration: A process which promotes biological degradation of organic matter in water. The process may be passive (as when waste is exposed to air), or active (as when a mixing or bubbling device introduces the air).

Aeration Tank: A chamber used to inject air into water.

Aerobic: Life or processes that require, or are not destroyed by, the presence of oxygen.

Aerobic Composting: A method of composting organic wastes using bacteria that need oxygen. This requires that the waste is exposed to air, either via turning or by forcing air through pipes that pass through the material.

Aerobic Treatment: Process by which microbes decompose complex organic compounds in the presence of oxygen and use the liberated energy for reproduction and growth. (Such processes include extended aeration, trickling filtration, and rotating biological contactors.)

Aerosol: 1. Small droplets or particles suspended in the atmosphere, typically containing sulfur. They are usually emitted naturally (e.g. in volcanic eruptions) and as the result of anthropogenic (human) activities such as burning fossil fuels. 2. The pressurized gas used to propel substances out of a container.

Aerosol: A finely divided material suspended in air or other gaseous environments.

Affected Landfill: Under the Clean Air Act, landfills that meet criteria for capacity, age, and emissions rates set by the EPA. They are required to collect and combust their gas emissions.

Affected Public: 1.The people who live and/or work near a hazardous waste site. 2. The human population adversely impacted following exposure to a toxic pollutant in food, water, air, or soil.

Afterburner: In incinerator technology, a burner located so that the combustion gasses are made to pass through its flame in order to remove smoke and odors. It may be attached to or be separated from the incinerator proper.

After-Market: The broad term that applies to any change after the original purchase, such as adding equipment not a part of the original purchase. As applied to alternative fuel vehicles, it refers to conversion devices or kits for conventional fuel vehicles.

AFUE (Annual Fuel Utilization Efficiency): A measure of heating efficiency, in consistent units, determined by applying the federal test method for furnaces. This value is intended to represent the ratio of heat transferred to the conditioned space by the fuel energy supplied over one year.

Age Tank: A tank used to store a chemical solution of known concentration for feed to a chemical feeder. Also called a day tank.

Aggregator: An entity responsible for planning, scheduling, accounting, billing, and settlement for energy deliveries from the aggregator's portfolio of sellers and/or buyers. Aggregators seek to bring together customers or generators so they can buy or sell power in bulk, making a profit on the transaction.

Agricultural Pollution: Farming wastes, including runoff and leaching of pesticides and fertilizers; erosion and dust from plowing; improper disposal of animal manure and carcasses; crop residues, and debris.

Agricultural Waste: Poultry and livestock manure, and residual materials in liquid or solid form generated from the production and marketing of poultry, livestock or fur-bearing animals; also includes grain, vegetable, and fruit harvest residue.

Agro-ecosystem: Land used for crops, pasture, and livestock; the adjacent uncultivated land that supports other vegetation and wildlife; and the associated atmosphere, the underlying soils, groundwater, and drainage networks.

Air Binding: Situation where air enters the filter media and harms both the filtration and backwash processes.

Air Change: The replacement of a quantity of air in a space within a given period of time, typically expressed as air changes per hour. If a building has one air change per hour, this is equivalent to all of the air in the building being replaced in a one-hour period.

Air Changes Per Hour (ACH): The movement of a volume of air in a given period of time; if a house has one air change per hour, it means that the air in the house will be replaced in a one-hour period.

Air Cleaning: Indoor-air quality-control strategy to remove various airborne particulates and/or gasses from the air. Most common methods are particulate filtration, electrostatic precipitation, and gas sorption.

Air Conditioner: An assembly of equipment for air treatment consisting of a means for ventilation, air circulation, air cleaning, and heat transfer (either heating or cooling). The unit usually consists of an evaporator or cooling coil, and an electrically-driven compressor and condenser combination.

Air Contaminant: Any particulate matter, gas, or the combination thereof, other than water vapor.

Air Curtain: A method of containing oil spills. Air bubbling through a perforated pipe causes an upward water flow that slows the spread of oil. It can also be used to stop fish from entering the polluted water.

Air Exchange Rate: The rate at which outside air replaces indoor air in a given space.

Air film: A layer of still air adjacent to a surface which provides some thermal resistance.

Air Film Coefficient: A measure of the heat transfer through an air film.

Air Gap: The open vertical gap or empty space that separates drinking water supply to be protected from another water system in a treatment plant or other location. The open gap protects the drinking water from contamination by backflow or back siphonage.

Air Handling Unit: Equipment that includes a fan or blower, heating and/or cooling coils, regulator controls, condensate drain pans, and air filters.

Air Mass: A large volume of air with certain meteorological or polluted characteristics--e.g., a heat inversion or smogginess--while in one location. The characteristics can change as the air mass moves away.

Air/Oil Table: The surface between the vadose zone and ambient oil; the pressure of oil in the porous medium is equal to atmospheric pressure.

Air Padding: Pumping dry air into a container to assist with the withdrawal of liquid or to force a liquefied gas such as chlorine out of the container.

Air Permeability: Permeability of soil with respect to air. Important to the design of soil-gas surveys. Measured in darcys or centimetres-per-second.

Air Plenum: Any space used to convey air in a building, furnace, or structure. The space above a suspended ceiling is often used as an air plenum.

Air Pollutant: Any substance in air that could, in high enough concentration, harm man, other animals, vegetation, or material. Pollutants may include almost any natural or artificial composition of airborne matter capable of being airborne. They may be in the form of solid particles, liquid droplets, gasses, or in combination thereof. Generally, they fall into two main groups: (1) those emitted directly from identifiable sources and (2) those produced in the air by interaction between two or more primary pollutants, or by reaction with normal atmospheric constituents, with or without photo activation. Exclusive of pollen, fog, and dust, which are of natural origin, about 100 contaminants have been identified. Air pollutants are often grouped in categories for ease in classification; some of the categories are solids, sulfur compounds, volatile organic chemicals, particulate matter, nitrogen compounds, oxygen compounds, halogen compounds, a radioactive compound, and odors.

Air Pollution: The presence of contaminants or pollutant substances in the air that interfere with human health or welfare, or produce other harmful environmental effects.

Air Pollution Control Device: Mechanism or equipment that cleans emissions generated by a source (e.g. an incinerator, industrial smokestack, or an automobile exhaust system) by removing pollutants that would otherwise be released to the atmosphere.

Air Pollution Episode: A period of abnormally high concentration of air pollutants, often due to low winds and temperature inversion that can cause illness and death.

Air Quality Control Region:

Air Quality Criteria: The levels of pollution and lengths of exposure above which adverse health and welfare effects may occur.

Air Quality Standards: The level of pollutants prescribed by regulations that are not be exceeded during a given time in a defined area.

Air Sparging: Injecting air or oxygen into an aquifer to strip or flush volatile contaminants as air bubbles up through the ground water and is captured by a vapor extraction system.

Air Stripping: A treatment system that removes volatile organic compounds (VOCs) from contaminated ground water or surface water by forcing an airstream through the water and causing the compounds to evaporate.

Air Toxics: Any air pollutant for which a national ambient air quality standard (NAAQS) does not exist (i.e. excluding ozone, carbon monoxide, PM-10, sulfur dioxide, nitrogen oxide) that may reasonably be anticipated to cause cancer; respiratory, cardiovascular, or developmental effects; reproductive dysfunctions, neurological disorders, heritable gene mutations, or other serious or irreversible chronic or acute health effects in humans.

Airborne Particulates: Total suspended particulate matter found in the atmosphere as solid particles or liquid droplets. The chemical composition of particulates varies widely, depending on location and time of year. Sources of airborne particulates include dust, emissions from industrial processes, combustion products from the burning of wood and coal, combustion products associated with motor vehicle or non-road engine exhausts, and reactions to gasses in the atmosphere.

Airborne Release: Release of any pollutant into the air.

Airspace: The projected bank cubic yards (BCY) of the landfill to be filled with waste as determined by survey and/or other engineering techniques.

Alachlor: A herbicide, marketed under the trade name Lasso, used mainly to control weeds in corn and soybean fields.

Alar: Trade name for daminozide, a pesticide that makes apples redder, firmer, and less likely to drop off trees before growers are ready to pick them. It is also used to a lesser extent on peanuts, tart cherries, concord grapes, and other fruits.

Alcohol Fuels: A class of liquid chemicals that have certain combinations of hydrogen, carbon, and oxygen, and that are capable of being used as fuel.

Aldicarb: An insecticide sold under the trade name Temik. It is made from ethyl isocyanate.

Algae: Simple rootless plants that grow in sunlit waters in proportion to a number of available nutrients. They can affect water quality adversely by lowering the dissolved oxygen in the water. They are food for fish and small aquatic animals.

Algal Blooms: Sudden spurts of algal growth, which can affect water quality adversely and indicate potentially hazardous changes in local water chemistry.

Algicide: Substance or chemical used specifically to kill or control algae.

Aliquot: A measured portion of a sample taken for analysis. One or more aliquots make up a sample.

Alkaline: The condition of water or soil which contains a sufficient amount of alkali substance to raise the pH above 7.0.

Alkalinity: The capacity of bases to neutralize acids. An example is a lime added to lakes to decrease acidity.

Allergen: A substance that causes an allergic reaction in individuals sensitive to it.

Alluvial: Relating to and/or sand deposited by flowing water.

Alternate Method: Any method of sampling and analyzing for an air or water pollutant that is not a reference or equivalent method but that has been demonstrated in specific cases-to EPA's satisfaction-to produce results adequate for compliance monitoring.

Alternative Compliance: A policy that allows facilities to choose among methods for achieving emission-reduction or risk-reduction instead of command-and control regulations that specify standards and how to meet them. Use of a theoretical emissions bubble over a facility to cap the amount of pollution emitted while allowing the company to choose where and how (within the facility) it complies.

Alternating Current (AC): Flow of electricity that constantly changes direction between positive and negative sides. Almost all power produced by electric utilities in the United States moves in current that shifts direction at a rate of 60 times per second.

Alternative Fuels: 1. Substitutes for traditional liquid, oil-derived motor vehicle fuels like gasoline and diesel. Includes mixtures of alcohol-based fuels with gasoline, methanol, ethanol, compressed natural gas, and others. 2. as defined by the National Energy Policy Act (EP Act) the fuels are: methanol, denatured ethanol and other alcohols, separately or in mixtures of 85 percent by volume or more (or other percentage not less than 70 percent as determined by U.S. Department of Energy rule) with gasoline or other fuels; CNG; LNG; LPG; hydrogen; "coal-derived liquid fuels;" fuels "other than alcohols" derived from "biological materials;" electricity, or any other fuel determined to be "substantially not petroleum" and yielding "substantial energy security benefits and substantial environmental benefits."

Alternative Fuel Vehicle (AFV): Motor vehicles that run on fuels other than petroleum-based fuels. As defined by the National Energy Policy Act (EP Act), this excludes reformulated gasoline as an alternative fuel.

Ambient Air: Any unconfined portion of the atmosphere: open air, surrounding air.

Ambient Measurement: A measurement of the concentration of a substance or pollutant within the immediate environs of an organism; taken to relate it to the amount of possible exposure.

Ambient Medium: Material surrounding or contacting an organism (e.g. outdoor air, indoor air, water, or soil, through which chemicals or pollutants can reach the organism.

Ambient Temperature: Temperature of the surrounding air or another medium.

Ampere (Amp): The unit of measure that tells how much electricity flows through a conductor. It is like using cubic feet per second to measure the flow of water. For example, a 1,200 watt, 120-volt hair dryer pulls 10 amperes of electric current (watts divided by volts).

Amperometric Titration: A way of measuring concentrations of certain substances in water using an electric current that flows during a chemical reaction.

Anaerobic: A life or process that occurs in, or is not destroyed by, the absence of oxygen.

Anaerobic Decomposition: Reduction of the net energy level and change in chemical composition of organic matter caused by microorganisms in an oxygen-free environment.

Anaerobic Digestion: Anaerobic digestion is a biological process that produces a gas principally composed of methane (CH4) and carbon dioxide (CO2) otherwise known as biogas. These gasses are produced from organic wastes such as livestock manure and food processing waste (also known as anaerobic composting).

Angle of Incidence: The angle that the sun's rays make with a line perpendicular to a surface. The angle of incidence determines the percentage of direct sunshine intercepted by a surface.

Animal Dander: Tiny scales of animal skin, a common indoor air pollutant.

Animal Studies: Investigations using animals as surrogates for humans with the expectation that the results are pertinent to humans.

Animal Waste Conversion: Process of obtaining energy from animal wastes. This is a type of biomass energy.

Anisotropy: In hydrology, the conditions under which one or more hydraulic properties of an aquifer vary from a reference point.

Annual Maximum Demand: The greatest of all demands of the electrical load which occurred during a prescribed interval in a calendar year.

Annular Space, Annulus: The space between two concentric tubes or casings, or between the casing and the borehole wall.

ANSI: American National Standards Institute is the national organization that coordinates development and maintenance of consensus standards and sets rules for fairness in their development. ANSI also represents the USA in developing international standards.

Antagonism: Interference or inhibition of the effect of one chemical by the action of another.

Antarctic "Ozone Hole": Refers to the seasonal depletion of ozone in the upper atmosphere above a large area of Antarctica.

Anthracite: Hard coal, found deep in the earth. It burns very hotly, with little flame. It usually has a heating value of 12,000-15,000 British thermal units (Btus) per pound.

Anti-Degradation Clause: Part of federal air quality and water quality requirements prohibiting deterioration where pollution levels are above the legal limit.

Anti-Microbial: An agent that kills microbes.

Antimicrobial Preservative: Natural or synthetically derived chemical additive incorporated into/onto product surfaces to prevent microbial growth, odors and stains.

Antimony Trioxide: A compound used as a fire retardant and as a catalyst to manufacture PET (polyethylene terephthalate).

Appliance Efficiency Standards: Appliance Efficiency Standards regulate the minimum performance requirements for appliances and apply to refrigerators, freezers, room air conditioners, central air conditioners, gas space heaters, water heaters, plumbing fittings, fluorescent lamp ballasts and luminaries, and ignition devices for gas cooking appliances and gas pool heaters. New National Appliance Standards are in place for some of these appliances and will become effective for others at a future date.

Appliance Saturation: A percentage telling what proportion of all households in a given geographical area have a certain appliance.

Applied Dose: In exposure assessment, the amount of a substance in contact with the primary absorption boundaries of an organism (e.g. skin, lung tissue, gastrointestinal track) and available for absorption.

Aqueous: Something made up of water.

Aqueous Solubility: The maximum concentration of a chemical that will dissolve in pure water at a reference temperature.

Aquifer: An underground geological formation, or group of formations, containing water. Are sources of groundwater for wells and springs.

Aquifer Test: A test to determine hydraulic properties of an aquifer.

Aquitard: The geological formation that may contain groundwater but is not capable of transmitting significant quantities of it under normal hydraulic gradients. May function as confining bed.

Architectural Coatings: Coverings such as paint and roof tar that are used on exteriors of buildings.

Area Load: The total amount of electricity being used at a given point in time by all consumers in a utility's service territory.

Aromatics: A type of hydrocarbon, such as benzene or toluene, with a specific type of ring structure. Aromatics are sometimes added to gasoline in order to increase octane. Some aromatics are toxic.

Arsenicals: Pesticides containing arsenic.

Artesian (Aquifer or Well): Water held under pressure in porous rock or soil confined by impermeable geological formations.

Asbestos: A mineral fiber that can pollute air or water and cause cancer or asbestosis when inhaled. EPA has banned or severely restricted its use in manufacturing and construction.

Asbestos Abatement: Procedures to control fiber release from asbestos-containing materials in a building or to remove them entirely, including removal, encapsulation, repair, enclosure, encasement, and operations and maintenance programs.

Asbestos Assessment: In the asbestos-in-schools program, the evaluation of the physical condition and potential for damage of all friable asbestos containing materials and thermal insulation systems.

Asbestosis: A disease associated with inhalation of asbestos fibers. The disease makes breathing progressively more difficult and can be fatal.

Ash: Non-organic, non-flammable substance left over after the combustible material has been completely burned.

Assay: A test for a specific chemical, microbe, or effect.

Assessment Endpoint: In ecological risk assessment, an explicit expression of the environmental value to be protected; includes both an ecological entity and specifically attributed thereof. entity (e.g. salmon are a valued ecological entity; reproduction and population maintenance--the attribute--form an assessment endpoint.)

Assimilation: The ability of a body of water to purify itself of pollutants.

Assimilative Capacity: The capacity of a natural body of water to receive wastewaters or toxic materials without deleterious effects and without damage to aquatic life or humans who consume the water.

Associated Gas: Natural gas that can be developed for commercial use, and which is found in contact with oil in naturally occurring underground formations.

Association of Boards of Certification: An international organization representing boards which certify the operators of waterworks and wastewater facilities.

ATGAS: Synthetic gas produced by dissolving coal in a bath of molten iron. The process was developed by Applied Technology, Inc. Synthetic gas may be used as a substitute for natural gas in industrial and home uses.

ATOM: The smallest unit of an element consisting of a dense positively charged nucleus (of protons and neutrons) orbited by negatively charged electrons.

Atomic Energy Commission: The independent civilian agency of the federal government with the statutory responsibility to supervise and promote the use of nuclear energy. Functions were taken over in 1974 by the Energy Research and Development Administration (now part of the U.S. Department of Energy) and the Nuclear Regulatory Commission.

Atomic Nucleus: The positively charged core of an atom.

Attainment Area: An area considered to have air quality as good as or better than the national ambient air quality standards as defined in the Clean Air Act. An area may be an attainment area for one pollutant and a non-attainment area for others.

Attenuation: The process by which a compound is reduced in concentration over time, through absorption, adsorption, degradation, dilution, and/or transformation. an also be the decrease with distance of sight caused by attenuation of light by particulate pollution.

Attractant: A chemical or agent that lures insects or other pests by stimulating their sense of smell.

Attrition: Wearing or grinding down of a substance by friction. Dust from such processes contributes to air pollution.

Autoclaving: Sterilization via a pressurized, high-temperature steam process.

Auxiliary Energy Subsystem: Equipment using conventional fuel to supplement the energy output of a solar system. This might be, for example, an oil- fueled generator that adds to the electrical output of substitutes for the solar system during long overcast periods when there is not enough sunlight.

Auxiliary Equipment: Extra machinery needed to support the operation of a power plant or other large facility.

Availability Session: Informal meeting at a public location where interested citizens can talk with EPA and state officials on a one-to-one basis.

Available Chlorine: A measure of the amount of chlorine available in chlorinated lime, hypochlorite compounds, and other materials used as a source of chlorine when compared with that of liquid or gaseous chlorines.

Average Cost: The revenue requirement of a utility divided by the utility's sales. Average cost typically includes the costs of existing power plants, transmission, and distribution lines, and other facilities used by a utility to serve its customers. It also included operating and maintenance, tax, and fuel expenses.

Average Demand: The energy demand in a given geographical area over a period of time. For example, the number of kilowatt-hours used in a 24-hour period, divided by 24, tells the average demand for that period.

Average Hydro: Rain, snow and runoff conditions that provide water for hydroelectric generation equal to the most commonly occurring levels. Average hydro usually is a mean indicating the levels experienced most often in a 104-year period.

Avoided Cost: The cost a utility would incur to generate the next increment of electric capacity using its own resources; many landfill gas projects' buy back rates are based on avoided costs.

Azimuth: The angular distance between true south and the point on the horizon directly below the sun. Typically used as an input for opaque surfaces and windows in computer programs for calculating the energy performance of buildings.

A-Scale Sound Level: A measurement of sound approximating the sensitivity of the human ear, used to note the intensity or annoyance level of sounds.


Back Pressure: A pressure that can cause water to backflow into the water supply when a user's waste water system is at a higher pressure than the public system.

Backflow/Back Siphonage: A reverse flow condition created by a difference in water pressures that causes water to flow back into the distribution pipes of a drinking water supply from any source other than the intended one.

Background Level: 1. The concentration of a substance in an environmental media (air, water, or soil) that occurs naturally or is not the result of human activities. 2. In exposure assessment the concentration of a substance in a defined control area, during a fixed period of time before, during, or after a data-gathering operation.

Backwashing: Reversing the flow of water back through the filter media to remove entrapped solids.

Backyard Composting: Diversion of organic food waste and yard trimmings from the municipal waste stream by composting hem in one's yard through controlled decomposition of organic matter by bacteria and fungi into a humus-like product. It is considered source reduction, not recycling because the composted materials never enter the municipal waste stream.

BACT - Best Available Control Technology: An emission limitation based on the maximum degree of emission reduction (considering energy, environmental, and economic impacts) achievable through application of production processes and available methods, systems, and techniques. BACT does not permit emissions in excess of those allowed under any applicable Clean Air Act provisions. Use of the BACT concept is allowable on a case by case basis for major new or modified emissions sources in attainment areas and applies to each regulated pollutant.

Bacteria (Singular: bacterium): Microscopic living organisms that can aid in pollution control by metabolizing organic matter in sewage, oil spills or other pollutants. However, bacteria in soil, water or air can also cause human, animal, and plant health problems.

Bactericide: A pesticide used to control or destroy bacteria, typically in the home, schools, or hospitals.

Baffle: A flat board or plate, deflector, guide, or similar device constructed or placed in flowing water or slurry systems to cause more uniform flow velocities to absorb energy and to divert, guide, or agitate liquids.

Baffle Chamber: In incinerator design, a chamber designed to promote the settling of fly ash and coarse particulate matter by changing the direction and/or reducing the velocity of the gasses produced by the combustion of the refuse or sludge.

Baghouse: A combustion plant emission control device that consists of an array of fabric filters through which flue gasses pass in an incinerator flue. Particles are trapped and thus prevented from passing into the atmosphere.

Baghouse Filter: Large fabric bag, usually made of glass fibers, used to eliminate intermediate and large (greater than 20 PM in diameter) particles. This device operates like the bag of an electric vacuum cleaner, passing the air and smaller particles while entrapping the larger ones.

Bailer: A pipe with a valve at the lower end, used to remove slurry from the bottom or side of a well as it is being drilled, or to collect groundwater samples from wells or open boreholes. 2. A tube of varying length.

Balanced Schedule: A Scheduling Coordinator's schedule is balanced when generation, adjusted for transmission losses, equals demand.

Baler: A piece of equipment used to compress and form recycled material into bales.

Baling: Compacting solid waste into blocks to reduce volume and simplify handling.

Ballast: A device that provides starting voltage and limits the current during normal operation in electrical discharge lamps (such as fluorescent lamps).

Ballistic Separator: A machine that sorts organic from inorganic matter for composting.

Band Application: The spreading of chemicals over, or next to, each row of plants in a field.

Banking: A system for recording qualified air emission reductions for later use in the bubble, offset, or netting transactions.

Bar Screen: In wastewater treatment, a device used to remove large solids.

Barrel: In the petroleum industry, a barrel is 42 U.S. gallons. One barrel of oil has an energy content of 6 million British thermal units. It takes one barrel of oil to make enough gasoline to drive an average car from Los Angeles to San Francisco and back (at 18 miles per gallon over the 700-mile round trip). Barrels Per Day Equivalent (BPD-Equivalent): A unit of measure that tells how much oil would have to be burned to produce the same amount of energy.

Barrel Sampler: Open-ended steel tube used to collect soil samples.

Barrier Coating(s): A layer of a material that obstructs or prevents passage of something through a surface that is to be protected; e.g., grout, caulk, or various sealing compounds; sometimes used with polyurethane membranes to prevent corrosion or oxidation of metal surfaces, chemical impacts on various materials, or, for example, to prevent radon infiltration through walls, cracks, or joints in a house.

Basal Application: In pesticides, the application of a chemical on plant stems or tree trunks just above the soil line.

Basalt: Consistent year-round energy use of a facility; also refers to the minimum amount of electricity supplied continually to a facility.

Base Load: The lowest level of power production needs during a season or year.

Base Load Unit: A power generating facility that is intended to run constantly at near capacity levels, as much of the time as possible.

Basel Convention: An international agreement on the control of transboundary movements of hazardous wastes and their disposal, drawn up in March 1989 in Basel, Switzerland, with over 100 countries as signatories.

Baseline Forecast: A prediction of future energy needs which does not take into account the likely effects of new conservation programs that have not yet been started.

Base Rate: That portion of the total electric or gas rate covering the general costs of doing business unrelated to fuel expenses.

Battery: A device that stores energy and produces electric current by chemical action.

BDT: Acronym for "bone dry tons." This is a measurement of biomass that has zero percent moisture content. Amounts are usually given in BDT/year.

Bean Sheet: Common term for a pesticide data package record.

Bed Load: Sediment particles resting on or near the channel bottom that is pushed or rolled along by the flow of water.

Bench-scale Tests: Laboratory testing of potential cleanup technologies.

Benefit-Cost Analysis: An economic method for assessing the benefits and costs of achieving alternative health-based standards at given levels of health protection.

Benthic/Benthos: An organism that feeds on the sediment at the bottom of a water body such as an ocean, lake, or river.

Bentonite: A colloidal clay, expansible when moist, commonly used to provide a tight seal around a good casing.

Benzene: A type of colorless liquid hydrocarbon that can be used as a motor fuel. Its chemical symbol is C6H6.

Beryllium: A metal hazardous to human health when inhaled as an airborne pollutant. It is discharged by machine shops, ceramic and propellant plants, and foundries.

Best Available Control Measures (BACM): A term used to refer to the most effective measures (according to EPA guidance) for controlling small or dispersed particulates and other emissions from sources such as roadway dust, soot, and ash from woodstoves and open burning of the rush, timber, grasslands, or trash.

Best Available Control Technology (BACT): For any specific source, the currently available technology producing the greatest reduction of air pollutant emissions, taking into account energy, environmental, economic, and other costs.

Best Available Control Technology (BACT): The most stringent technology available for controlling emissions; major sources are required to use BACT unless it can be demonstrated that it is not feasible for energy, environmental, or economic reasons.

Best Demonstrated Available Technology (BDAT): As identified by EPA, the most effective commercially available means of treating specific types of hazardous waste. The BDATs may change with advances in treatment technologies.

Best Management Practice (BMP): Methods that have been determined to be the most effective, practical means of preventing or reducing pollution from non-point sources.

Bi-Fuel Vehicle: A vehicle with two separate fuel systems designed to run on either fuel, using only one fuel at a time. These systems are advantageous for drivers who do not always have access to an alternative fuel refueling station. Bi-fuel systems are usually used in light-duty vehicles. One of the two fuels is typically an alternative fuel.

Bi-Gas: A process being developed as a means of making synthetic gas from coal. The synthetic gas would be intended to substitute for natural gas in meeting industrial and home energy needs.

Bilateral Contract: A two-party agreement for the purchase and the sale of energy products and services.

Bimetal: Beverage containers with steel bodies and aluminum tops; handled differently from pure aluminum in recycling.

Bioaccumulants: Substances that increase in concentration in living organisms as they take in contaminated air, water, or food because the substances are very slowly metabolized or excreted.

Bioaccumulation: An increase in the concentration of a chemical in biological organism overtime, compared to the chemical’s concentration in the environment.

Bioassay: A test to determine te relative strength of a substance by comparing its effect on a test organism with that of a standard preparation.

Bio-availability: Degree of ability to be absorbed and ready to interact in organism metabolism.

Bio-based Product: A product (other than food or feed) that is produced from renewable agricultural (plant, animal, and marine) or forestry materials.

Biochemical Oxygen Demand (BOD): A measure of the amount of oxygen consumed in the biological processes that break down organic matter in water. The greater the BOD, the greater the degree of pollution.

Bio-concentration: The accumulation of a chemical in tissues of a fish or other organism to levels greater than in the surrounding medium.

Bio-conversion: Processes that use plants or micro-organisms to change one form of energy into another. For example, an experimental process uses algae to convert solar energy into gas that could be used for fuel.

Biodegradable: Capable of decomposing under natural conditions.

Biodegradable Material: Any organic material that can be broken down by microorganisms into simpler, more stable compounds. Most organic wastes (e.g., food, paper) are biodegradable.

Biodegradation: The process by which a substance or material is broken down (or decomposed or metabolized) by microorganisms and reduce to organic or inorganic molecules which can further utilize by living systems.

Biodiesel: A biodegradable transportation fuel for use in diesel engines that is produced through the transesterification of organically- derived oils or fats. It may be used either as a replacement for or as a component of diesel fuel.

Biodiversity: Refers to the variety and variability among living organisms and the ecological complexes in which they occur. Diversity can be defined as the number of different items and their relative frequencies. For biological diversity, these items are organized at many levels, ranging from complete ecosystems to the biochemical structures that are the molecular basis of heredity. Thus, the term encompasses different ecosystems, species, and genes.

Biofuels: A fuel made wholly or partially from industrial by-products obtained as a result of transforming a plant or animal material.

Biogas: Produced by the biological breakdown of organic matter in the absence of oxygen in a process known as anaerobic digestion; It contains a high proportion of methane (50%) and thus has a high calorific and energy potential. In our industries, gas is produced in landfills, methane production units and the sludge digesters of wastewater treatment plants. It must be collected to prevent pollution and environmental damage, specifically odors and the heightened greenhouse effect. Biogas can be recovered and used as a renewable energy in place of fossil fuel.

Biological Contaminants: Living organisms or derivates (e.g. viruses, bacteria, fungi, and mammal and bird antigens) that can cause harmful health effects when inhaled, swallowed, or otherwise taken into the body.

Biological Control: In pest control, the use of animals and organisms that eat or otherwise kill or out-compete pests.

Biological Integrity: The ability to support and maintain balanced, integrated, functionality in the natural habitat of a given region. The concept is applied primarily in drinking water management.

Biological Magnification: Refers to the process whereby certain substances such as pesticides or heavy metals move up the food chain, work their way into rivers or lakes, and are eaten by aquatic organisms such as fish, which in turn are eaten by large birds, animals or humans. The substances become concentrated in tissues or internal organs as they move up the chain.

Biological Measurement: A measurement taken in a biological medium. For exposure assessment, it is related to the measurement is taken to relate it to the established internal dose of a compound.

Biological Medium: One of the major component of an organism; e.g. blood, fatty tissue, lymph nodes or breath, in which chemicals can be stored or transformed.

Biological Oxidation: Decomposition of complex organic materials by microorganisms. Occurs in self-purification of water bodies and in activated sludge wastewater treatment.

Biological Oxygen Demand (BOD): An indirect measure of the concentration of biologically degradable material present in organic wastes. It usually reflects the amount of oxygen consumed in five days by biological processes breaking down organic waste.

Biological pesticides: Certain microorganism, including bacteria, fungi, viruses, and protozoa that are effective in controlling pests. These agents usually do not have toxic effects on animals and people and do not leave toxic or persistent chemical residues in the environment.

Biological Stressors: Organisms accidentally or intentionally dropped into habitats in which they do not evolve naturally; e.g. gypsy moths, Dutch elm disease, certain types of algae, and bacteria.

Biological Treatment: A treatment technology that uses bacteria to consume organic waste.

Biologically Effective Dose: The amount of a deposited or absorbed compound reaching the cells or target sites where adverse effect occur, or where the chemical interacts with a membrane.

Biologicals: Vaccines, cultures and other preparations made from living organisms and their products, intended for use in diagnosing, immunizing, or treating humans or animals, or in related research.

Biomass: Energy resources derived from organic matter. These include wood, agricultural waste and other living-cell material that can be burned to produce heat energy. They also include algae, sewage and other organic substances that may be used to make energy through chemical processes.

Biomass: Any organic matter that can be used as fuel to generate energy. Biomass, also known as biofuels or bio-energy, is obtained from organic matter either directly from plants or indirectly from industrial, commercial, domestic or agricultural products. The use of biomass is classed as a 'carbon-neutral' process because the carbon dioxide released during the generation of energy from biomass is balanced by that absorbed by plants during their growth.

Biome: The entire community of living organisms in a single major ecological area.

Biomimicry: The study of nature and imitation of nature’s forms. The process of learning from and then emulating life’s genius.

Bio-monitoring: 1. The use of living organisms to test the suitability of effluents for discharge into receiving waters and to test the quality of such waters downstream from the discharge. 2. Analysis of blood, urine, tissues, etc. to measure chemical exposure in humans.

Bioreactor: Bio-reaction accelerates the production of landfill gas by recovering leachate and reincorporating it into the waste mass. Adding moisture and nutrients to the bacteria at work in the mass accelerates the breakdown process, facilitating the recovery of methane usable for energy. Collecting and recovering methane offer both environmental and economic advantages: it reduces methane's greenhouse effect and is a significant source of energy.

Bioremediation: Use of living organisms to clean up oil spills or remove other pollutants from soil, water, or wastewater; use of organisms such as non-harmful insects to remove agricultural pests or counteract diseases of trees, plants, and garden soil.

Biosensor: The analytical device comprising a biological recognition element (e.g. enzyme, receptor, DNA, antibody, or microorganism) in intimate contact with an electrochemical, optical, thermal, or acoustic signal transducer that together permits analyses of chemical properties or quantities. Shows potential development in some areas, including environmental monitoring.

Biosphere: The zone at and adjacent to the earth's surface where all life exists; all living organisms of the earth.

Biostabilizer: A machine that converts solid waste into compost by grinding and aeration.

Biota: The animal and plant life of a given region.

Biotechnology: Techniques that use living organisms or parts of organisms to produce a variety of products (from medicines to industrial enzymes) to improve plants or animals or to develop microorganisms to remove toxics from bodies of water, or act as pesticides.

Biotic Community: A naturally occurring assemblage of plants and animals that live in the same environment and are mutually sustaining and interdependent.

Biotransformation: Conversion of a substance into other compounds by organisms; includes biodegradation.

Bituminous Coal: Soft coal containing large amounts of carbon. It has a luminous flame and produces a great deal of smoke.

Blackwater: Water that contains an animal, human, or food waste.

Blood Products: Any product derived from human blood, including but not limited to blood plasma, platelets, red or white corpuscles, and derived licensed products such as interferon.

Bloom: A proliferation of algae and/or higher aquatic plants in a body of water; often related to pollution, especially when pollutants accelerate growth.

BOD5: The amount of dissolved oxygen consumed in five days by biological processes breaking down organic matter.

Body Burden: The amount of a chemical stored in the body at a given time, especially a potential toxin in the body as the result of exposure.

Bog: A type of wetland that accumulates appreciable peat deposits. Bogs depend primarily on precipitation for their water source and are usually acidic and rich in plant residue with a conspicuous mat of living green moss.

Boiler: A closed vessel designed to transfer heat produced by combustion or electric resistance to water. Boilers may provide hot water or steam.

Boiler (Wheelabrator): A device used to absorb the heat released during the combustion process of burning waste. This combustion produces steam that can be sold or converted into electrical power.

Boiling Water Reactor (BWR): A nuclear power unit in which water used as a coolant is allowed to boil at the core. The resulting steam may be used to drive electric turbines.

Boom: 1. A floating device used to contain oil on a body of water. 2. A piece of equipment used to apply pesticides from a tractor or truck.

Borehole: Hole made with drilling equipment.

Botanical Pesticide: A pesticide whose active ingredient is a plant-produced chemical such as nicotine or strychnine. Also called a plant-derived pesticide.

Bottle Bill: Proposed or enacted legislation which requires a returnable deposit on beer or soda containers and provides for a retail store or other redemption. Such legislation is designed to discourage use of throw-away containers.

Bottled Gas: The liquified petroleum gasses propane and butane, contained under moderate pressure (about 125 pounds per square inch and 30 pounds per square inch respectively), in cylinders.

Bottoming Cycle: A means to increase the thermal efficiency of a steam electric generating system by converting some waste heat from the condenser into electricity rather than discharging all of it into the environment.

Bottom Ash: The non-airborne combustion residue from burning pulverized coal in a boiler; the material which falls to the bottom of the boiler and is removed mechanically; a concentration of non-combustible materials, which may include toxics.

Bottom Ash: Bottom ash is the slag and solid residue left after waste combustion and recovered from the bottom of furnaces. A distinction is made between municipal waste bottom ash and hazardous waste bottom ash. Current regulations divide the former into three categories: recyclable, treatable and storable. “Recyclable” bottom ash that meets specific technical requirements can be used to build roads. Special industrial waste bottom ash is treated in landfills or recycled in some cases.

Bottom Land Hardwoods: Forested freshwater wetlands adjacent to rivers in the southeastern United States, especially valuable for wildlife breeding, nesting and habitat.

Bounding Estimate: An estimate of exposure, dose, or risk that is higher than that incurred by the person in the population with the currently highest exposure, dose, or risk. Bounding estimates are useful in developing statements that exposures, doses, or risks are not greater than an estimated value. Brackish: Mixed fresh and salt water.

Breakpoint Chlorination: Addition of chlorine to water until the chlorine demand has been satisfied.

Breakthrough: A crack or break in a filter bed that allows the passage of floc or particulate matter through a filter; will cause an increase in filter effluent turbidity.

Breathing Zone: Area of air in which an organism inhales.

Breeder: A nuclear reactor that produces more fuel than it consumes. The breeder, invented in the United States, is used as a power source in several European countries.

Brine Mud: Waste material, often associated with well-drilling or mining, composed of mineral salts or other inorganic compounds.

British Thermal Unit (Btu): The standard measure of heat energy. It takes one Btu to raise the temperature of one pound of water by one degree Fahrenheit at sea level. For example, it takes about 2,000 Btu to make a pot of coffee. One Btu is equivalent to 252 calories, 778 foot-pounds, 1055 joules, and 0.293 watt-hours. Note: In the abbreviation, only the B is capitalized.

Broadcast Application: The spreading of pesticides over an entire area.

Broker: A retail agent who buys and sells power. The agent may also aggregate customers and arrange for transmission, firming and other ancillary services as needed.

Brownfields: Abandoned, idled, or under-used industrial and commercial facilities/sites where expansion or redevelopment is complicated by real or perceived environmental contamination. They can be in urban, suburban, or rural areas. EPA's Brownfields initiative helps communities mitigate potential health risks and restore the economic viability of such areas or properties.

Brownout: A controlled power reduction in which the utility decreases the voltage on the power lines, so customers receive weaker electric current. Brownouts can be used if total power demand exceeds the maximum available supply. The typical household does not notice the difference.

Bubble: A system under which existing emissions sources can propose alternate means to comply with a set of emissions limitations; under the bubble concept, sources can control more than required at one emission point where control costs are relatively low in return for a comparable relaxation of controls at a second emission point where costs are higher.

Buffer: A solution or liquid whose chemical makeup is such that it minimizes changes in pH when acids or bases are added to it.

Buffer Strips: Strips of grass or other erosion-resisting vegetation between or below cultivated strips or fields.

Building Cooling Load: The hourly amount of heat that must be removed from a building to maintain indoor comfort (measured in British thermal units (Btus).

Building Envelope: The exterior surface of a building's construction--the walls, windows, floors, roof, and floor. It is also called building the shell.

Building Related Illness (BRI): Diagnosable illness with symptoms that can be identified and with a cause that can be directly attributed to airborne building pollutants (e.g. Legionnaire’s Disease, hypersensitivity pneumonitis).

Bulk Power Supply: Often this term is used interchangeably with wholesale power supply. In broader terms, it refers to the aggregate of electric generating plants, transmission lines, and related-equipment. The term may refer to those facilities within one electric utility, or within a group of utilities in which the transmission lines are interconnected.

Bulk Sample: A small portion (usually thumbnail size) of a suspect asbestos-containing building material collected by an asbestos inspector for laboratory analysis to determine asbestos content.

Bulky Waste: Waste from household activities that, because of its volume or weight, is not included in the usual collection system, but needs special handling. For the most part, bulky waste is only an occasional occurrence. It includes:

• used household appliances

• debris

• construction and demolition waste

• green household waste

Bunker C Fuel Oil: A very heavy substance, left over after other fuels have been distilled from crude oil. It is also called NO. 6 FUEL, it is used in power plants, ships, and large heating installations.

Burial Ground (Graveyard): A disposal site for radioactive waste materials that uses earth or water as a shield.

Busbar: In electric utility operations, a busbar is a conductor that serves as a common connection for two or more circuits. It may be in the form of metal bars or high-tension cables.

Butane: A hydrocarbon gas found in the earth along with natural gas and oil. Butane turns into a liquid when put under pressure. It is sold as bottled gas. It is used to run heaters, stoves, and motors, and to help make petrochemicals.

Buy-Back Center: Facility where individuals or groups bring recyclables in return for payment.

Buy Through: An agreement between utility and customer to import power when the customer's service would otherwise be interrupted.

Buyer: An entity that purchases electrical energy or services from the Power Exchange (PX) or through a bilateral contract on behalf of end-use customers.

By-product: Material, other than the principal product, generated as a consequence of an industrial process or as a breakdown product in a living system.

By-product: Anything produced in an industrial or biological process in addition to the principal product; a secondary and sometimes unexpected or unintended result.

Cadmium (Cd): A heavy metal that accumulates in the environment.

Call Back: A provision included in some power sale contracts that lets the supplier stop delivery when the power is needed to meet certain other obligations.

Calorie: One energy calorie is equivalent to 4.2 joules. Thus, it takes 500,000 calories of energy to boil a pot of coffee. One food calorie equals 1,000 energy calories.

Calorie (energy calorie -"c"): Any of several approximately equal values of heat, each measured as the quantity of heat required to raise the temperature of 1 gram of water by 1 degree Celsius from a standard initial temperature, esp. from 3.98 degrees Celsius. 14.5 degrees Celsius, or 19.5 degrees Celsius, at 1-atmosphere pressure. A calorie is the unit of heat equal to 4.184 joules.

Calorific Value: Amount of heat generated by a given mass of fuel when it is completely burned. It is measured in joules per kilogram.

Cancellation: Refers to Section 6 (b) of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) which authorizes cancellation of a pesticide registration if unreasonable adverse effects to the environment and public health develop when a product is used according to widespread and commonly recognized practice, or if its labelling or other material required to be submitted does not comply with FIFRA provisions.

Cap: A layer of clay, or other impermeable material installed over the top of a closed landfill to prevent entry of rainwater and minimize leachate.

Capacity: The amount of electric power for which a generating unit, generating station, or other electrical apparatus is rated either by the user or manufacturer. The term is also used for the total volume of natural gas that can flow through a pipeline over a given amount of time, considering such factors as compression and pipeline size.

There are various types of electricity capacity:

Dependable Capacity: The systems' ability to carry the electric power for the time interval and period specific, when related to the characteristics of the load to be supplied. Dependable capacity is determined by such factors as capability, operating power factor, weather, and a portion of the load the station is to supply.

Installed (or Nameplate) Capacity: The total manufacturer-rated capacities of equipment such as turbines, generators, condensers, transformers, and other system components.

Peaking Capacity: The capacity of generating equipment intended for operation during the hours of highest daily, weekly or seasonal loads.

Purchased Capacity: The amount of energy and capacity available for purchase from outside the system.

Reserve Capacity: Extra generating capacity available to meet peak or abnormally high demands for power and to generate power during scheduled or unscheduled outages. Units available for service, but not maintained at operating temperature, are termed "cold." those units ready and available for service, though not in actual operation, are termed "hot."

Capacity Assurance Plan: A state-wide plan which supports a state's ability to manage the hazardous waste generated within its boundaries over a twenty year period.

Capacity Factor: A percentage that tells how much of a power plant's capacity is used over time. For example, typical plant capacity factors range as high as 80 percent for geothermal and 70 percent for co-generation.

Capacity Release: A secondary market for capacity that is contracted by a customer which is not using all of its capacity.

Capillary Action: Movement of water through very small spaces due to molecular forces called capillary forces.

Capillary Fringe: The porous material just above the water table which may hold water by capillarity (a property of surface tension that draws water upwards) in the smaller void spaces.

Capillary Fringe: The zone above the water table within which the porous medium is saturated by water under less than atmospheric pressure.

Capping: This is the process of placing the final cover material on the landfill.

Captive Customer: A customer who does not have realistic alternatives to buying power from the local utility, even if that customer had the legal right to buy from competitors.

Capture Efficiency: The fraction of organic vapors generated by a process that is directed to an abatement or recovery device.

Carbon Absorber: An add-on control device that uses activated carbon to absorb volatile organic compounds from a gas stream. (The VOCs are later recovered from the carbon.)

Carbon Adsorption: A treatment system that removes contaminants from ground water or surface water by forcing it through tanks containing activated carbon treated to attract the contaminants.

Carbon Credits: Carbon credits are created when a project reduces or avoids the emission of greenhouse gasses, such as carbon dioxide (CO2) and methane (CH4). The carbon credits are measured against a baseline.

Carbon Dioxide (CO2): A colorless, odorless, non-poisonous gas that is a normal part of the air. Carbon dioxide, also called CO2, is exhaled by humans and animals and is absorbed by green growing things and by the sea.

Carbon Dioxide (CO2): A colorless, odorless gas, formed naturally by decomposition, combustion, breathing, etc. CO2 contributes to global warming.

Carbon Monoxide (CO): A colorless, odorless, highly poisonous gas made up of carbon and oxygen molecules formed by the incomplete combustion of carbon or carbonaceous material, including gasoline. It is a major air pollutant on the basis of weight.

Carbon Tetrachloride (CC14): Compound consisting of one carbon atom ad four chlorine atoms, once widely used as an industrial raw material, as a solvent, and in the production of CFCs. Use as a solvent ended when it was discovered to be carcinogenic.

Carbon Trading: The UK Emissions Trading Scheme, launched in April 2002, is the world's first economy-wide national-level greenhouse gas trading scheme. Emissions trading is designed to allow businesses to reduce their emissions of greenhouse gasses in the most economically efficient way. The EU-wide non-voluntary scheme should start in 2005.

Carboxyhemoglobin: Hemoglobin in which the iron is bound to carbon monoxide (CO) instead of oxygen.

Carcinogens: Potential cancer-causing agents in the environment. They include among others: industrial chemical compounds found in food additives, pesticides, and fertilizers, drugs, toy, household cleaners, toiletries, and paints. Naturally occurring ultraviolet solar radiation is also a carcinogen.

Carrier: 1.The inert liquid or solid material in a pesticide product that serves as a delivery vehicle for the active ingredient. Carriers do not have toxic properties of their own. 2. Any material or system that can facilitate the movement of a pollutant into the body or cells.

Carrying Capacity: 1. In recreation management, the amount of use a recreation area can sustain without loss of quality. 2. In wildlife management, the maximum number of animals an area can support during a given period.

Case Study: A brief fact sheet providing risk, cost, and performance information on alternative methods and other pollution prevention ideas, compliance initiatives, voluntary efforts, etc.

Cask: A thick-walled container (usually lead) used to transport radioactive material. It is also called a coffin.

Catalyst: A substance that changes the speed or yield of a chemical reaction without being consumed or chemically changed by the chemical reaction.

Catalytic Converter: An air pollution abatement device that removes pollutants from motor vehicle exhaust, either by oxidizing them into carbon dioxide and water or reducing them to nitrogen.

Catalytic Incinerator: A control device that oxidizes volatile organic compounds (VOCs) by using a catalyst to promote the combustion process. Catalytic incinerators require lower temperatures than conventional thermal incinerators, thus saving fuel and other costs.

Catalytic Cracking: A refinery process that converts a high-boiling range fraction of petroleum (gas oil) to gasoline, olefin feed for alkylation, distillate, fuel oil and fuel gas by use of a catalyst and heat.

Categorical Pre-treatment Standard: A technology-based effluent limitation for an industrial facility discharging into a municipal sewer system. It is analogous in stringency to Best Availability Technology (BAT) for direct dischargers.

Cathodic Protection: A technique to prevent corrosion of a metal surface by making it the cathode of an electrochemical cell.

Caulking: Material used to make an air-tight seal by filling in cracks, such as those around windows and doors.

Cavitation: The formation and collapse of gas pockets or bubbles on the blade of an impeller or the gate of a valve; the collapse of these pockets or bubbles drives water with such force that it can cause pitting of the gate or valve surface.

Cell: A waterproof pit containing subcells into which waste is deposited in a landfill. A landfill is composed of several cells. Each one is hydraulically independent and designed to facilitate the recovery of landfill gas and the collection of leachate. A geomembrane liner and draining materials ensure the cells are waterproof. The cells are surrounded by waterproof barriers. The whole landfill is also surrounded by a boundary fence. The height and slope of the barriers, the distance from cells to the outer limit of the operation, and inspections are all covered by regulations.

Cells: 1. In solid waste disposal, holes where waste is dumped, compacted and covered with layers of dirt on a daily basis. 2. The smallest structural part of living matter capable of functioning as an independent unit.

Celsius: A temperature scale based on the freezing (0 degrees) and boiling (100 degrees) points of water. Abbreviated as C in second and subsequent references in the text. Formerly known as Centigrade. To convert Celsius to Fahrenheit, multiply the number by 9, divide by 5, and add 32.

For example: 10 degrees Celsius x 9 = 90; 90 / 5 = 18; 18 + 32 = 50 degrees Fahrenheit.

Cementitious: Densely packed and non-fibrous friable materials.

Central Collection Point: Location where a generator of regulated medical waste consolidates wastes originally generated at various locations in his facility. The wastes are gathered together for treatment on-site or for transportation elsewhere for treatment and/or disposal. This term could also apply to community hazardous waste collections, industrial and other waste management systems.

Centrifugal Collector: A mechanical system using centrifugal force to remove aerosols from a gas stream or to remove water from sludge.

CERCLIS: The federal Comprehensive Environmental Response, Compensation, and Liability Information System is a database that includes all sites which have been nominated for investigation by the Superfund program.

CFC’s (Chlorofluorocarbons or Chlorinated Fluorocarbons): A family of artificially produced chemicals receiving much attention for their role in stratospheric ozone depletion. On a per molecule basis, these chemicals are several thousand times more effective as greenhouse gasses than carbon dioxide. Since they were introduced in the mid-1930s, CFCs have been used as refrigerants, solvents and in the production of foam material. The 1987 Montreal protocol on CFCs seeks to reduce their production by one-half by the year 1998.

Channelization: Straightening and deepening streams so water will move faster, a marsh-drainage tactic that can interfere with waste assimilation capacity, disturb fish and wildlife habitats, and aggravate flooding.

Characteristic: Any one of the four categories used in defining hazardous waste: ignitability, corrosivity, reactivity, and toxicity.

Check-Valve Tubing Pump: Water sampling tool also referred to as a water Pump.

Chemical Case: For purposes of review and regulation, the grouping of chemically similar pesticide active ingredients (e.g. salts and esters of the same chemical) into chemical cases.

Chemical Compound: A distinct and pure substance formed by the union or two or more elements in definite proportion by weight.

Chemical Element: A fundamental substance comprising one kind of atom; the simplest form of matter.

Chemical Energy: The energy generated when a chemical compound combusts, decomposes, or transforms to produce new compounds.

Chemical Oxygen Demand (COD): A measure of the oxygen required to oxidize all compounds, both organic and inorganic, in water.

Chemical Stressors: Chemicals released to the environment through industrial waste, auto emissions, pesticides, and other human activity that can cause illnesses and even death in plants and animals.

Chemical Treatment: Any one of a variety of technologies that use chemicals or a variety of chemical processes to treat waste.

Chemical Waste Management (CWM): The operating name of Waste Management's hazardous waste landfills. WM currently owns and operates five hazardous waste landfills in the U.S.

Chemocar: A special vehicle for the collection of toxic and hazardous wastes from residences, shops, and institutions.

Chemosterilant: A chemical that controls pests by preventing reproduction.

Child Resistant Packaging (CRP): Packaging that protects children or adults from injury or illness resulting from accidental contact with or ingestion of residential pesticides that meet or exceed specific toxicity levels.The term is also used for protective packaging of medicines.

Chiller: A device that generates a cold liquid that is circulated through an air-handling unit's cooling coil to cool the air supplied to the building.

Chilling Effect: The lowering of the Earth's temperature because of increased particles in the air blocking the sun's rays.

Chisel Plowing: Preparing croplands by using a special implement that avoids complete inversion of the soil as in conventional plowing. Chisel plowing can leave a protective cover or crops residues on the soil surface to help prevent erosion and improve filtration.

Chlorinated Hydrocarbons: 1. Chemicals containing only chlorine, carbon, and hydrogen. These include a class of persistent, broad-spectrum insecticides that linger in the environment and accumulate in the food chain. Among them are DDT, aldrin, dieldrin, heptachlor, chlordane, lindane, endrin, Mirex, hexachloride, and toxaphene. Other examples include TCE, used as an industrial solvent. 2. Any chlorinated organic compounds including chlorinated solvents such as dichloromethane, trichloromethylene, chloroform.

Chlorinated Solvent: An organic solvent containing chlorine atoms (e.g. methylene chloride and trichloromethane). Uses of chlorinated solvents are including aerosol spray containers, in highway paint, and dry cleaning fluids.

Chlorination: The application of chlorine to drinking water, sewage, or industrial waste to disinfect or to oxidize undesirable compounds.

Chlorinator: A device that adds chlorine, in gas or liquid form, to water or sewage to kill infectious bacteria.

Chlorine-Contact Chamber: That part of a water treatment plant where effluent is disinfected by chlorine.

Chlorofluorocarbon (CFC): A compound of consisting of chlorine, fluorine, and carbon. CFC’s are very stable in the troposphere. Class of volatile, non-reactive, non-corrosive, non-flammable and easily liquefied gasses, typically used in refrigeration and believed to be responsible for the deterioration of the stratospheric ozone.

Chlorofluorocarbons (CFCs): A family of inert, nontoxic, and easily liquefied chemicals used in refrigeration, air conditioning, packaging, insulation, or as solvents and aerosol propellants. Because CFCs are not destroyed in the lower atmosphere they drift into the upper atmosphere where their chlorine components destroy ozone.

Chlorophenoxy: A class of herbicides that may be found in domestic water supplies and cause adverse health effects.

Chlorosis: Discoloration of normally green plant parts caused by disease, lack of nutrients, or various air pollutants.

Cholinesterase: An enzyme found in animals that regulate nerve impulses by the inhibition of acetylcholine. Cholinesterase inhibition is associated with a variety of acute symptoms such as nausea, vomiting, blurred vision, stomach cramps, and rapid heart rate.

Chronic Effect: An adverse effect on a human or animal in which symptoms recur frequently or develop slowly over a long period of time.

Chronic Exposure: Multiple exposures occurring over an extended period of time or over a significant fraction of an animal's or human's lifetime (Usually seven years to a lifetime.)

Chronic Toxicity: The capacity of a substance to cause long-term poisonous health effects in humans, animals, fish, and other organisms.

Circle of Influence: The circular outer edge of a depression produced in the water table by the pumping of water from a well.

Circuit: One complete run of a set of electric conductors from a power source to various electrical devices (appliances, lights, etc.) and back to the same power source.

Cistern: Small tank or storage facility used to store water for a home or farm; often used to store rain water.

Clarification: Clearing action that occurs during wastewater treatment when solids settle out. This is often aided by centrifugal action and chemically induced coagulation in wastewater.

Clarifier: A tank in which solids settle to the bottom and are subsequently removed as sludge.

Class I Area: Under the Clean Air Act. a Class I area is one in which visibility is protected more stringently than under the national ambient air quality standards; includes national parks, wilderness areas, monuments, and other areas of special national and cultural significance.

Class I Substance: One of the several groups of chemicals with an ozone depletion potential of 0.2 or higher, including CFCS, Halons, Carbon Tetrachloride, and Methyl Chloroform (listed in the Clean Air Act), and HBFCs and Ethyl Bromide (added by EPA regulations).

Class II Substance: A substance with an ozone depletion potential of less than 0.2. All HCFCs are currently included in this classification.

Clay Soil: Soil material containing more than 40 percent clay, less than 45 percent sand, and less than 40 percent silt.

Clean Air Act: The federal statute that regulates air emissions from the area, stationary and mobile resources. This law authorizes the U.S. Environmental Protection Agency to establish National Ambient Air Standards (NAAQS) to protect public health and the environment.

Clean Air Act Amendments of 1990: A major overhaul of the earlier Clean Air Act of 1970. Changes included requiring a number of industries, including solid waste combustion units, to meet Maximum Achievable Control Technology standards for air emissions.

Clean Coal Technology: Any technology not in widespread use prior to the Clean Air Act Amendments of 1990. This Act will achieve significant reductions in pollutants associated with the burning of coal.

Clean Development Mechanism (CDM): The Clean Development Mechanism encourages the realization of environmental projects in developing countries. The entity that finances the project earns emission credits.

Clean Fuel Vehicle: Is frequently incorrectly used interchangeably with "alternative fuel vehicle." Generally, refers to vehicles that use low-emission, clean-burning fuels. Public Resources Code Section 25326 defines clean fuels, for purposes of the section only, as fuels designated by ARB for use in LEVs, ULEVs or ZEVs and include, but are not limited to, electricity, ethanol, hydrogen, liquefied petroleum gas, methanol, natural gas, and reformulated gasoline.

Clean Fuels: Blends or substitutes for gasoline fuels, including compressed natural gas, methanol, ethanol, and liquified petroleum gas.

Cleaner production: Processes designed to reduce the wastes generated by production.

Cleaner Technologies Substitutes Assessment: A document that systematically evaluates the relative risk, performance, and cost trade-offs of technological alternatives; serves as a repository for all the technical data (including methodology and results) developed by a DfE or other pollution prevention or education project.

Cleanup: Actions taken to deal with a release or threat of release of a hazardous substance that could affect humans and/or the environment. The term "cleanup" is sometimes used interchangeably with the terms remedial action, removal action, response action, or corrective action.

Clear Cut: Harvesting all the trees in one area at one time, a practice that can encourage fast rainfall or snowmelt runoff, erosion, sedimentation of streams and lakes, and flooding, and destroys vital habitat.

Clear Water Act: The Federal Water Pollution Control Act Amendments of 1972, as amended in 1977, became commonly known as the Clean Water Act. The Act established the basic structure for regulating discharges of pollutants into the waters of the United States.

Clear Well: A reservoir for storing filtered water of sufficient quantity to prevent the need to vary the filtration rate with variations in demand. Also used to provide chlorine contact time for disinfection.

Climate Change (also referred to as 'global climate change'): The term 'climate change' is sometimes used to refer to all forms of climatic inconsistency, but because the Earth's climate is never static, the term is more properly used to imply a significant change from one climatic condition to another. In some cases, 'climate change' has been used synonymously with the term, 'global warming'; scientists, however, tend to use the term in the wider sense to also include natural changes in climate.

Climate Change Levy: The Climate Change Levy is a tax on energy use in industry, commerce, agriculture and the public sector.

Climate Zone: A geographical area is a state that has particular weather patterns. These zones are used to determine the type of building standards that are required by law.

Cloning: In biotechnology, obtaining a group of genetically identical cells from a single cell; making identical copies of a gene.

Closed-Loop: A type of manufacturing process that utilizes a material flow in order to minimize waste. A manufacture that re-uses the waste/spoilage and reuses own waste.

Closed-Loop Recycling: Reclaiming or reusing wastewater for non-potable purposes in an enclosed process.

Closed Site (Landfill): A landfill that has reached its permitted waste capacity and has been permanently capped and certified as closed by the appropriate state regulatory agency.

Closure: The procedure a landfill operator must follow when a landfill reaches its legal capacity for solid ceasing acceptance of solid waste and placing a cap on the landfill site.

Clunkers: It is also known as gross-polluting or super- emitting vehicles, i.e., vehicles that emit far in excess of the emission standards by which the vehicle was certified when it was new.

Co-fire: Burning of two fuels in the same combustion unit; e.g., coal and natural gas, or oil and coal.

Coagulation: Clumping of particles in wastewater to settle out impurities, often induced by chemicals such as lime, alum, and iron salts.

Coal: Black or brown rock, formed under pressure from organic fossils in prehistoric times that is mined and burned to produce heat energy.

Coal Bed Methane: Methane which is still locked into the vast reserves of coal and coal measures strata that remain unworked. The concept of this is referred to as Coal Bed Methane (CBM) since it involves directly drilling into unworked coal and coal measures strata to release the methane locked within it rather than utilizing methane released as a result of mining activities.

Coal Cleaning Technology: A precombustion process by which coal is physically or chemically treated to remove some of its sulfur so as to reduce sulfur dioxide emissions.

Coal Conversion: Changing coal into synthetic gas or liquid fuels.

Coal Gasification: Conversion of coal to a gaseous product by one of the several available technologies.

Coal Mine Methane: Methane continues to emit from the coal mine after closure, and recently the concept of collecting the gas from abandoned mines to provide an energy source which would otherwise be waste has been developed.

Coal Oil: Oil that can be obtained by distilling bituminous coal.

Coal Seam: A mass of coal, occurring naturally at a particular location that can be commercially mined.

Coal Slurry Pipeline: A pipe system that transports pulverized coal suspended in water.

Coastal Zone: Lands and waters adjacent to the coast that exert an influence on the uses of the sea and its ecology, or whose uses and ecology are affected by the sea.

Co-disposal: The disposal of different types of waste in one area of a landfill or dump. For instance, sewage sludge may be disposed of with regular solid wastes.

Coefficient of Haze (COH): A measurement of visibility interference in the atmosphere.

Cogeneration: The consecutive generation of useful thermal and electric energy from the same fuel source. Co-generators use the waste heat created by one process, for example during manufacturing, to produce steam which is used, in turn, to spin a turbine and generate electricity.

Cogeneration: Cogeneration means the sequential use of energy for the production of electrical and useful thermal energy. The sequence can be thermal use followed by power production or the reverse, subject to the following standards:

a) At least 5 percent of the cogeneration project's total annual energy output shall be in the form of useful thermal energy.

b) Where useful thermal energy follows power production, the useful annual power output plus one-half the useful annual thermal energy output equals not less than 42.5 percent of any natural gas and oil energy input.

Coke: A porous solid left over after the incomplete burning of coal or of crude oil.

Coke Oven: An industrial process which converts coal into coke, one of the basic materials used in blast furnaces for the conversion of iron ore into iron.

Coke Oven Gas: Gas given off by coke ovens. Coke oven gas is interchangeable with goal gas.

Cold Temperature CO: A standard for automobile emissions of carbon monoxide (CO) emissions to be met at a low temperature (i.e. 20 degrees Fahrenheit). Conventional automobile catalytic converters are not efficient in cold weather until they warm up.

Coliform Index: A rating of the purity of water based on a count of fecal bacteria.

Coliform Organism: Microorganisms found in the intestinal tract of humans and animals. Their presence in water indicates fecal pollution and potentially adverse contamination by pathogens.

Collection: The process of picking up wastes from residences, businesses, or a collection point, loading them into a vehicle, and transporting them to a processing, transfer, or disposal site.

Collector: Public or private hauler that collects nonhazardous waste and recyclable materials from residential, commercial, institutional and industrial sources.

Collector Sewers: Pipes used to collect and carry wastewater from individual sources to an interceptor sewer that will carry it to a treatment facility.

Colloids: Very small, finely divided solids (that do not dissolve) that remain dispersed in a liquid for a long time due to their small size and electrical charge.

Combined Cycle Plant: An electric generating station that uses waste heat from its gas turbines to produce steam for conventional steam turbines.

Combined Hydronic Space/Water Heating: A system in which both space heating and domestic water heating are provided by the same water heater(s).

Combined Sewer Overflows: Discharge of a mixture of storm water and domestic waste when the flow capacity of a sewer system is exceeded during rainstorms.

Combined Sewers: A sewer system that carries both sewage and storm-water runoff. Normally, its entire flow goes to a waste treatment plant, but during a heavy storm, the volume of water may be so great as to cause overflows of untreated mixtures of storm water and sewage into receiving waters. Storm-water runoff may also carry toxic chemicals from industrial areas or streets into the sewer system.

Combustibles: Burnable materials in the waste stream, including paper, plastics, wood, and food and garden wastes.

Combustion: 1. Burning, or rapid oxidation, accompanied by the release of energy in the form of heat and light. 2. Refers to controlled burning of waste, in which heat chemically alters organic compounds, converting into stable inorganics such as carbon dioxide and water.

Combustion Chamber: The actual compartment where waste is burned in an incinerator.

Combustion Product: Substance produced during the burning or oxidation of a material.

Command Post: Facility located at a safe distance upwind from an accident site, where the on-scene coordinator, responders, and technical representatives make response decisions, deploy manpower and equipment, maintain liaison with news media, and handle communications.

Command-and-Control Regulations: Specific requirements prescribing how to comply with specific standards defining acceptable levels of pollution.

Commercial Customer: A segment of the business that is made up of the commercial and industrial collection.

Commercial Waste: All solid waste emanating from business establishments such as stores, markets, office buildings, restaurants, shopping centers, and theaters.

Commercial Waste Management Facility: A treatment, storage, disposal, or transfer facility which accepts waste from a variety of sources, as compared to a private facility which normally manages a limited waste stream generated by its own operations.

Commercialization: Programs or activities that increase the value or decrease the cost of integrating new products or services into the electricity sector.

Commingled: Mixed recyclables that are collected together after having been separated from mixed MSW.

Commingled Recyclables: Mixed recyclables that are collected together.

Comminuter: A machine that shreds or pulverizes solids to make waste treatment easier.

Comminution: Mechanical shredding or pulverizing of waste. Used in both solid waste management and wastewater treatment.

Communal Collection: A system of collection in which individuals bring their waste directly to a central point, from which it is collected.

Community: In ecology, an assemblage of populations of different species within a specified location in space and time. Sometimes, a particular sub grouping may be specified, such as the fish community in a lake or the soil arthropod community in a forest.

Compact Fluorescent Lamp (CFL): Small fluorescent lamps used as more efficient alternatives to incandescent lighting. It is also called PL, CFL, Twin-Tube, or BIAX lamps.

Compaction: Reduction of the bulk of solid waste by rolling and tamping.

Compactor vehicle: A collection vehicle using high-power mechanical or hydraulic equipment to reduce the volume of solid waste.

Comparative Risk Assessment: Process that generally uses the judgment of experts to predict effects and set priorities among a wide range of environmental problems.

Competitive Bidding (Electricity): A procedure that utilities in many states use to select suppliers of new electric capacity and energy. Under competitive bidding, an electric utility solicits bids from prospective power generators to meet current or future power demands. When offers from independent power producers began exceeding utility needs in the mid-1980s, utilities and state regulators began using competitive bidding systems to select among numerous supply alternatives.

Competitive Bidding (Municipal Solid Waste): A procedure that municipalities use to select vendors to collect and/or dispose of the solid waste within the municipality.

Complete Treatment: A method of treating water that consists of the addition of coagulant chemicals, flash mixing, coagulation-flocculation, sedimentation, and filtration. Also called conventional filtration.

Compliance Coal: Any coal that emits less than 1.2 pounds of sulfur dioxide per million Btu when burned. Also known as low sulfur coal.

Compliance Coating: A coating whose volatile organic compound content does not exceed that allowed by regulation.

Compliance Cycle: The 9-year calendar year cycle, beginning January 1, 1993, during which public water systems must monitor. Each cycle consists of three 3-year compliance periods.

Compliance Monitoring: Collection and evaluation of data, including self-monitoring reports, and verification to show whether pollutant concentrations and loads contained in permitted discharges are in compliance with the limits and conditions specified in the permit.

Compliance Schedule: A negotiated agreement between a pollution source and a government agency that specifies dates and procedures by which a source will reduce emissions and, thereby, comply with a regulation.

Composite Liner: A liner system for a land-fill consisting of an engineered soil layer and a synthetic sheet of material.

Composite Sample: A series of water samples taken over a given period of time and weighted by flow rate.

Compost: A humus or soil-like material created from aerobic, microbial decomposition of organic materials such as food scraps, yard trimmings, and manure.

Compostable: Processing the ability to breakdown into or otherwise become part of, usable compost in a safe and timely manner.

Composting: The controlled biological decomposition of organic material in the presence of air to form a humus-like material. Controlled methods of composting include mechanical mixing and aerating, ventilating the materials by dropping them through a vertical series of aerated chambers, or placing the compost in piles out in the open air and mixing it or turning it periodically.

Composting: A biological process that accelerates the breakdown of organic waste by introducing air, producing compost. The chemical reactions involved in composting release heat, which sanitizes the compost, i.e., eliminates the pathogenic agents in the incoming waste. Compost can be used as an organic amendment, to improve soil structure, or as a fertilizer to nourish plants (Biological decomposition of solid organic materials by bacteria, fungi, and other organisms into a soil-like product).

Composting Facilities: 1. An offsite facility where the organic component of municipal solid waste is decomposed under controlled conditions; aerobic process in which organic materials are ground or shredded and then decomposed to humus in windrow piles or in mechanical digesters, drums, or similar enclosures.

Composting Rejects: Waste exiting a composting facility as not suitable for organic recycling.

Compressed Natural Gas (CNG): An alternative fuel for motor vehicles; considered one of the cleanest because of low hydrocarbon emissions and its vapors are relatively non-ozone producing. However, vehicles fueled with CNG do emit a significant quantity of nitrogen oxides. Natural gas that has been compressed under high pressure, typically between 2,000 and 3,600 pounds per square inch, held in a container. The gas expands when released for use as a fuel.

Concentration: The relative amount of a substance mixed with another substance. An example is five ppm of carbon monoxide in air or 1 mg/l of iron in the water.

Condensate: 1.Liquid formed when warm landfill gas cools as it travels through a collection system. 2. Water created by cooling steam or water vapor.

Condensate Return System: System that returns the heated water condensing within steam piping to the boiler and thus saves energy.

Condenser: A heat exchanger in which the refrigerant, compressed to a hot gas, is condensed to liquid by rejecting heat.

Conditional Registration: Under special circumstances, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) permit registration of pesticide products that is "conditional" upon the submission of additional data. These special circumstances include a finding by the EPA Administrator that a new product or use of an existing pesticide will not significantly increase the risk of unreasonable adverse effects. A product containing a new (previously unregistered) active ingredient may be conditionally registered only if the Administrator finds that such conditional registration is in the public interest, that a reasonable time for conducting the additional studies has not elapsed, and the use of the pesticide for the period of conditional registration will not present an unreasonable risk.

Conductance: A rapid method of estimating the dissolved solids content of water supply by determining the capacity of a water sample to carry an electrical current. Conductivity is a measure of the ability of a solution to carry and electrical current.

Conduction: The transfer of heat energy through a material (solid, liquid or gas) by the motion of adjacent atoms and molecules without gross displacement of the particles.

Conductivity: A measure of the ability of a solution to carry an electrical current.

Cone of Depression: A depression in the water table that develops around a pumped well.

Cone of Influence: The depression, roughly conical in shape, produced in a water table by the pumping of water from a well.

Cone Penterometer Testing (CPT): A direct push system used to measure lithology based on soil penetration resistance. Sensors in the tip of the cone of the DP rod measure tip resistance and side-wall friction, transmitting electrical signals to digital processing equipment on the ground surface.

Confined Aquifer: An aquifer in which ground water is confined under pressure which is significantly greater than atmospheric pressure.

Confluent Growth: A continuous bacterial growth covering all or part of the filtration area of a membrane filter in which the bacteria colonies are not discrete.

Congestion: A condition that occurs when insufficient transfer capacity is available to implement all of the preferred schedules simultaneously.

Conservation: Preserving and renewing, when possible, human and natural resources. The use, protection, and improvement of natural resources according to principles that will ensure their highest economic or social benefits.

Conservation Easement: Easement restricting a landowner to land uses that that are compatible with long-term conservation and environmental values.

Constituent(s) of Concern: Specific chemicals that are identified for evaluation in the site assessment process.

Construction and Demolition Debris: Waste generated by construction and demolition of buildings, such as bricks, concrete, drywall, lumber, miscellaneous metal parts and sheets, packaging materials, etc.

Construction and Demolition (C&D): A waste stream that is primarily received from construction sites. Some examples of C&D waste include, but are not limited to, concrete, rebar, wood, paneling, linoleum, and carpet.

Construction and Demolition Waste: Waste building materials, dredging materials, tree stumps, and rubble resulting from construction, remodeling, repair, and demolition of homes, commercial buildings and other structures and pavements. It may contain lead, asbestos, or other hazardous substances.

Consumptive Water Use: Water removed from available supplies without return to a water resources system, e.g. water used in manufacturing, agriculture, and food preparation.

Contact Pesticide: A chemical that kills pests when it touches them, instead of by ingestion. Also, soil that contains the minute skeletons of certain algae that scratch and dehydrate waxy-coated insects.

Container: Any receptacle used to accumulate waste from residential, commercial and industrial sites. Containers vary in size and type according to the needs of the customer or restrictions of the community. Containers are also referred to as dumpsters.

Contaminant: Any physical, chemical, biological, or radiological substance or matter that has an adverse effect on air, water, or soil.

Contamination: Introduction into water, air, and soil of microorganisms, chemicals, toxic substances, wastes, or wastewater in a concentration that makes the medium unfit for its next intended use. Also applies to surfaces of objects, buildings, and various household and agricultural use products.

Contamination Source Inventory: An inventory of contaminant sources within delineated State Water-Protection Areas.

Contingency Planning: The Energy Commission's strategy to respond to impending energy emergencies such as curtailment or shortage of fuel or power because of natural disasters or the result of human or political causes, or a clear threat to public health, safety or welfare. The contingency plan specifies state actions to alleviate the impacts of a possible shortage or disruption of petroleum, natural gas or electricity. The plan is reviewed and updated at least every five years, with the last plan being adopted in 1993.

Continuous Sample: A flow of water, waste or other material from a particular place in a plant to the location where samples are collected for testing. May be used to obtaining grab or composite samples.

Contour Plowing: Soil tilling method that follows the shape of the land to discourage erosion.

Contour Strip Farming: A kind of contour farming in which row crops are planted in strips, between alternating strips of close-growing, erosion-resistant forage crops.

Contracts For Differences (CFD): A type of bilateral contract where the electric generation seller is paid a fixed amount over time which is a combination of the short-term market price and an adjustment with the purchaser for the difference. For example, a generator may sell a distribution company power for ten years at 6-cents/kilowatt-hour (kWh). That power is bid into Poolco at some low /kWh value (to ensure it is always taken). The seller then gets the market clearing price from the pool and the purchaser pays the producer the difference between the Poolco selling price and 6-cents/kWh (or vice versa if the pool price should go above the contract price).

Contract Labs: Laboratories under contract to EPA, which analyze samples taken from waste, soil, air, and water or carry out research projects.

Control Area: An electric power system, or a combination of electric power systems, to which a common automatic generation control (AGC) is applied to match the power output of generating units within the area to demand.

Controlled Dump: A planned landfill that incorporates to some extent some of the features of a sanitary landfill: siting with respect to hydro geological suitability, grading, compaction in some cases, leachate control, partial gas management, regular (not usually daily) cover, access control, basic record-keeping, and controlled waste picking.

Controlled Reaction: A chemical reaction under temperature and pressure conditions maintained within safe limits to produce a desired product or process.

Convection: Heat transfer by the movement of fluid.

Conventional Gas: Natural gas occurring in nature, as opposed to synthetic gas.

Conventional Pollutants: Statutorily listed pollutants understood well by scientists. These may be in the form of organic waste, sediment, acid, bacteria, viruses, nutrients, oil, and grease, or heat.

Conventional Site Assessment: Assessment in which most of the sample analysis and interpretation of data is completed off-site; process usually requires repeated mobilization of equipment and staff in order to fully determine the extent of contamination.

Conventional Systems: Systems that have been traditionally used to collect municipal wastewater in gravity sewers and convey it to a central primary or secondary treatment plant prior to discharge to surface waters.

Conventional Tilling: Tillage operations considered standard for a specific location and crop and that tend to bury the crop residues; usually considered as a base for determining the cost effectiveness of control practices.

Conversion: Device or kit by which a conventional fuel vehicle is changed to an alternative fuel vehicle.

Converted Vehicle: A vehicle originally designed to operate on gasoline that has been modified or altered to run on an alternative fuel.

Conversion Fuel Factor: A number stating units of one system in corresponding values of another system.

Converter: Any technology that changes the potential energy in a fuel into a different from of energy such as heat or motion. The term also is used to mean an apparatus that changes the quantity or quality of electrical energy.

Conveyance Loss: Water loss in pipes, channels, conduits, ditches by leakage or evaporation.

Cooling Capacity, Latent: An available refrigerating capacity of an air conditioning unit for removing latent heat from the space to be conditioned.

Cooling Capacity, Sensible: An available refrigerating capacity of an air conditioning unit for removing sensible heat from the space to be conditioned.

Cooling Capacity, Total: An available refrigerating capacity of an air conditioner for removing sensible heat and latent heat from the space to be conditioned.

Cooling Degree Day: A unit of measure that indicates how heavy the air conditioning needs are under certain weather conditions.

Cooling Load: The rate at which heat must be extracted from a space in order to maintain the desired temperature within the space.

Cooling Load Temperature Difference (CLTD): A value used in cooling load calculations for the effective temperature difference (delta T) across a wall or ceiling, which accounts for the effect of radiant heat as well as the temperature difference.

Cooling Tower: A structure that helps remove heat from water used as a coolant; e.g., in electric power generating plants.

Cooling Tower: Device which dissipates the heat from water-cooled systems by spraying the water through streams of rapidly moving air.

CO-OP: This is the commonly used term for a rural electric cooperative. Rural electric cooperatives generate and purchase wholesale power, arrange for the transmission of that power, and then distribute the power to serve the demand of rural customers. Co-ops typically become involved in ancillary services such as energy conservation, load management, and other demand-side management programs in order to serve their customers at least cost.

Cooperative (Electric Utility): A joint venture organized by consumers to make electric utility service available in their area.

Cop (Coefficient Of Performance): Used to rate the performance of a heat pump, the COP is the ratio of the rate of useful heat output delivered by the complete heat pump unit (exclusive of supplementary heating) to the corresponding rate of energy input, in consistent units and under specific conditions.

Cord: A measure of volume, 4 by 4 by 8 feet, used to define amounts of stacked wood available for use as fuel. Burned, a cord of wood produces about 5 million calories of energy.

Core: The uranium-containing heart of a nuclear reactor, where energy is released.

Corrosion: The dissolution and wearing away of metal caused by a chemical reaction such as between water and the pipes, chemicals touching a metal surface, or contact between two metals.

Corrosive: A chemical agent that reacts with the surface of a material causing it to deteriorate or wear away.

Cost/Benefit Analysis: A quantitative evaluation of the costs which would have incurred by implementing an environmental regulation versus the overall benefits to society of the proposed action.

Cost Recovery: A legal process by which potentially responsible parties who contributed to contamination at a Superfund site can be required to reimburse the Trust Fund for money spent during any cleanup actions by the federal government.

Cost Sharing: A publicly financed program through which society, as a beneficiary of environmental protection, shares part of the cost of pollution control with those who must actually install the controls. In Superfund, for example, the government may pay part of the cost of a cleanup action with those responsible for the pollution paying the major share.

Cost-Effective Alternative: An alternative control or corrective method identified after analysis as being the best available in terms of reliability, performance, and cost. Although costs are one important consideration, regulatory and compliance analysis does not require EPA to choose the least expensive alternative. For example, when selecting or approving a method for cleaning up a Superfund site, the Agency balances costs with the long-term effectiveness of the methods proposed and the potential danger posed by the site.

Cover Crop: A crop that provides temporary protection for delicate seedlings and/or provides a cover canopy for seasonal soil protection and improvement between normal crop production periods.

Cover Material: Soil used to cover compacted solid waste in a sanitary landfill.

Cradle-to-Cradle: A term used to describe a material or product that is recycled into a new or similar product at the end of its intended life.

Cradle-to-Grave: A term used to describe a material or product that is disposed (landfill, incineration, etc) of at the end of its intended life.

Cradle-to-Grave or Manifest System: A procedure in which hazardous materials are identified and followed as they are produced, treated, transported, and disposed of by a series of permanent, linkable, descriptive documents (e.g. manifests). Commonly referred to as the cradle-to-grave system.

Criteria: Descriptive factors taken into account by EPA in setting standards for various pollutants. These factors are used to determine limits on allowable concentration levels, and to limit the number of violations per year. When issued by EPA, the criteria provide guidance to the states on how to establish their standards.

Crop Consumptive Use: The amount of water transpired during plant growth plus what evaporated from the soil surface and foliage in the crop area.

Crop Rotation: Planting a succession of different crops on the same land area as opposed to planting the same crop time after time.

Cross Contamination: The movement of underground contaminants from one level or area to another due to invasive subsurface activities.

Cross-Connection: Any actual or potential connection between a drinking water system and an unapproved water supply or another source of contamination.

Crude Oil: Petroleum as found in the earth, before it is refined into oil products. It is also called CRUDE.

Crude Oil Stocks: Stocks held at refineries and at pipeline terminals. Does not include stocks held on leases (storage facilities adjacent to the wells).

Crumb Rubber: Ground rubber fragments the size of sand or silt used in rubber or plastic products, or processed further into reclaimed rubber or asphalt products.

Cryptosporidium: A protozoan microbe associated with the disease cryptosporidiosis in man. The disease can be transmitted through ingestion of drinking water, person-to-person contact, or other pathways, and can cause acute diarrhea, abdominal pain, vomiting, fever, and can be fatal as it was in the Milwaukee episode.

Cubic Feet Per Minute (CFM): A measure of the volume of a substance flowing through the air within a fixed period of time. With regard to indoor air, refers to the amount of air, in cubic feet, that is exchanged with outdoor air in a minute's time; i.e. the air exchange rate. A measure of flow rate.

Cubic Foot: The most common unit of measurement of natural gas volume. It equals the amount of gas required to fill a volume of one cubic foot under stated conditions of temperature, pressure and water vapor. One cubic foot of natural gas has an energy content of approximately 1,000 Btus. One hundred (100) cubic feet equals one therm (100 ft3 = 1 therm).

Cullet: Crushed glass.

Cultural Eutrophication: Increasing rate at which water bodies "die" by pollution from human activities.

Cultures and Stocks: Infectious agents and associated biologicals including cultures from medical and pathological laboratories; cultures and stocks of infectious agents from research and industrial laboratories; waste from the production of biologicals; discarded live and attenuated vaccines; and culture dishes and devices used to transfer, inoculate, and mix cultures.

Curbside Collection: Collection of compostables, recyclables, or trash at the edge of a sidewalk in front of a residence or shop.

Curb Stop: A water service shutoff valve located in a water service pipe near the curb and between the water main and the building.

Curbside Collection: Method of collecting recyclable materials at homes, community districts or businesses.

Curie: A measure of radioactivity.

Curing: Allowing partially composted materials to sit in a pile for a specified period of time as part of the maturing process in composting.

Cutie-Pie: An instrument used to measure radiation levels.

Cuttings: Spoils left by conventional drilling with hollow stem auger or rotary drilling equipment.

Cyclone Collector: A device that uses centrifugal force to remove large particles from the polluted air.

Daily Cover: The material used to cover the working face of a landfill at the close of each day.

Data Quality Objectives (DQOs): Qualitative and quantitative statements of the overall level of uncertainty that a decision-maker will accept in results or decisions based on environmental data. They provide the statistical framework for planning and managing environmental data operations consistent With User's Needs.

Day Ahead Market: The forward market for energy and ancillary services to be supplied during the settlement period of a particular trading day that is conducted by the ISO, the PX, and other Scheduling Coordinators. This market closes with the ISO's acceptance of the final day-ahead schedule.

Day Ahead Schedule: Day-ahead Schedule A schedule prepared by a Scheduling Coordinator or the ISO before the beginning of a trading day. This schedule indicates the levels of generation and demand scheduled for each settlement period of that trading day.

Day Lighting: The use of sunlight to supplement or replace electric lighting.

Day Lighting Control: A control system that varies the light output of an electric lighting system in response to variations in available daylight.

Day Tank: Another name for a deaerating tank.

DDT: The first chlorinated hydrocarbon insecticide chemical name: Dichloro-Diphenyl-Trichloroethane. It has a half-life of 15 years and can collect in fatty tissues of certain animals. EPA banned registration and interstate sale of DDT for virtually all but emergency uses in the United States in 1972 because of its persistence in the environment and accumulation in the food chain.

Dead End: The end of a water main which is not connected to other parts of the distribution system.

Deadmen: Anchors drilled or cemented into the ground to provide additional reactive mass for DP sampling rigs.

Decant: To draw off the upper layer of liquid after the heaviest material (a solid or another liquid) has settled.

Decay Products: Degraded radioactive materials, often referred to as "daughters" or "progeny"; radon decay products of most concern from a public health standpoint are polonium-214 and polonium-218.

Dechlorination: Removal of chlorine from a substance.

Decomposition: The breakdown of matter by bacteria and fungi, changing the chemical makeup and physical appearance of materials.

Decontamination: Removal of harmful substances such as noxious chemicals, harmful bacteria or other organisms, or radioactive material from exposed individuals, rooms and furnishings in buildings, or the exterior environment.

Deep-Well Injection: Deposition of raw or treated, filtered hazardous waste by pumping it into deep wells, where it is contained in the pores of the permeable subsurface rock.

Deep Mining: Extraction of coal or minerals at depths greater than 1,000 feet. Coal usually is deep-mined at not more than 1,500 feet.

Deflocculating Agent: A material added to a suspension to prevent settling.

Defluoridation: The removal of excess fluoride in drinking water to prevent the staining of teeth.

Defoliant: An herbicide that removes leaves from trees and growing plants.

Degasification: A water treatment that removes dissolved gasses from the water.

Degree-Day: A rough measure used to estimate the amount of heating required in a given area; is defined as the difference between the mean daily temperature and 65 degrees Fahrenheit. Degree-days are also calculated to estimate cooling requirements.

Delta: A difference in temperature. Often used in the context of the difference between the design indoor temperature and the outdoor temperature.

Demand: The rate at which energy is delivered to loads and scheduling points by generation, transmission or distribution facilities.

Demand Bid: Demand Bid A bid into the PX indicating a quantity of energy or an ancillary service that an eligible customer is willing to purchase and, if relevant, the maximum price that the customer is willing to pay.

Demand Billing: The electric capacity requirement for which a large user pays. It may be based on the customer's peak demand during the contract year, on a previous maximum or on an agreed minimum. Measured in kilowatts.

Demand Charge: The sum to be paid by a large electricity consumer for its peak usage level.

Demand Side Management (DSM): The methods used to manage energy demand including energy efficiency, load management, fuel substitution and load building.

Demand Side Waste Management: Planning, implementation, and evaluation of utility-sponsored programs to influence the amount or timing of customers' energy use. Prices whereby consumers use purchasing decisions to communicate to product manufacturers that they prefer environmentally sound products packaged with the least amount of waste, made from recycled or recyclable materials, and containing no hazardous substances.

Demineralization: A treatment process that removes dissolved minerals from water.

Demonstration: The application and integration of a new product or service into an existing or new system. Most commonly, demonstration involves the construction and operation of a new electric technology interconnected with the electric utility system to demonstrate how it interacts with the system. This includes the impacts the technology may have on the system and the impacts that the larger utility system might have on the functioning of the technology.

Denitrification: The biological reduction of nitrate to nitrogen gas by denitrifying bacteria in soil.

Dense Non-Aqueous Phase Liquid (DNAPL): Non-aqueous phase liquids such as chlorinated hydrocarbon solvents or petroleum fractions with a specific gravity greater than 1.0 that sink through the water column until they reach a confining layer. Because they are at the bottom of aquifers instead of floating on the water table, typical monitoring wells do not indicate their presence.

Density: A measure of how heavy a specific volume of a solid, liquid, or gas is in comparison to water, depending on the chemical.

Dependable Capacity: The system's ability to carry the electric power for the time interval and period specified. Dependable capacity is determined by such factors as capability, operating power factor and portion of the load the station is to supply.

Depletable Energy Sources: 1) electricity purchased from a public utility 2) energy obtained from burning coal, oil, natural gas or liquefied petroleum gasses. DEREGULATION - The elimination of regulation from a previously regulated industry or sector of an industry.

Depletion Curve: In hydraulics, a graphical representation of water depletion from storage-stream channels, surface soil, and groundwater. A depletion curve can be drawn for base flow, direct runoff, or total flow.

Depressurization: A condition that occurs when the air pressure inside a structure is lower that the air pressure outdoors. Depressurization can occur when household appliances such as fireplaces or furnaces, that consume or exhaust house air, are not supplied with enough makeup air. Radon may be drawn into a house more rapidly under depressurized conditions.

Derivatives: A specialized security or contract that has no intrinsic overall value, but whose value is based on an underlying security or factor as an index. A generic term that, in the energy field, may include options, futures, forwards, etc.

Dermal Absorption/Penetration: Process by which a chemical penetrates the skin and enters the body as an internal dose.

Dermal Exposure: Contact between a chemical and the skin.

Dermal Toxicity: The ability of a pesticide or toxic chemical to poison people or animals by contact with the skin.

DES: A synthetic estrogen, diethylstilbestrol is used as a growth stimulant in food animals. Residues in meat are thought to be carcinogenic.

Desalination: [Desalinization] (1) Removing salts from the ocean or brackish water by using various technologies. (2) Removal of salts from the soil by artificial means, usually leaching.

Desiccant: A chemical agent that absorbs moisture; some desiccants are capable of drying out plants or insects, causing death.

Design Capacity: The average daily flow that a treatment plant or other facility is designed to accommodate.

Design for the Environment (DfE): A concept or philosophy applied to the design process that advocates the reduction of environmental and human health impacts through materials selection and design strategies.

Design Value: The monitored reading used by EPA to determine an area's air quality status; e.g., for ozone, the fourth highest reading measured over the most recent three years is the design value.

Designated Pollutant: An air pollutant which is neither a criterion nor hazardous pollutant, as described in the Clean Air Act, but for which new source performance standards exist. The Clean Air Act does require states to control these pollutants, which include acid mist, total reduced sulfur (TRS), and fluorides.

Designated Uses: Those water uses identified in state water quality standards that must be achieved and maintained as required under the Clean Water Act. Uses can include cold water fisheries, public water supply, and irrigation.

Designed for Disassembly: The design and engineering of a product so that it can be dismantled for easier maintenance, repair recovery and reuse of components and materials.

Designer Bugs: Popular term for microbes developed through biotechnology that can degrade specific toxic chemicals at their source in toxic waste dumps or in ground water.

Destination Facility: The facility to which regulated medical waste is shipped for treatment and destruction, incineration, and/or disposal.

Destratification: Vertical mixing within a lake or reservoir to totally or partially eliminate separate layers of temperature, plant, or animal life.

Destroyed Medical Waste: Regulated medical waste that has been ruined, torn apart, or mutilated through thermal treatment, melting, shredding, grinding, tearing, or breaking, so that it is no longer generally recognized as medical waste, but has not yet been treated (excludes compacted regulated medical waste).

Destruction and Removal Efficiency (DRE): A percentage that represents the number of molecules of a compound removed or destroyed in an incinerator relative to the number of molecules entering the system (e.g. a DRE of 99.99 percent means that 9,999 molecules are destroyed for every 10,000 that enter; 99.99 percent is known as "four nines." For some pollutants, the RCRA removal requirement may be as stringent as "six nines").

Destruction Facility: A facility that destroys regulated medical waste.

Desulfurization: Removal of sulfur from fossil fuels to reduce pollution.

Detectable Leak Rate: The smallest leak (from a storage tank), expressed in terms of gallons- or liters-per-hour, that a test can reliably discern with a certain probability of detection or false alarm.

Detection Criterion: A predetermined rule to ascertain whether a tank is leaking or not. Most volumetric tests use a threshold value as the detection criterion.

Detection Limit: The lowest concentration of a chemical that can reliably be distinguished from a zero concentration.

Detention Time: 1. The theoretically calculated time required for a small amount of water to pass through a tank at a given rate of flow. 2. The actual time that a small amount of water is in a settling basin, flocculating basin, or rapid-mix chamber. 3. In storage reservoirs, the length of time water will be held before being used.

Detergent: Synthetic washing agent that helps to remove dirt and oil. Some contain compounds which kill useful bacteria and encourage algae growth when they are in wastewater that reaches receiving waters.

Development Effects: Adverse effects such as altered growth, structural abnormality, functional deficiency, or death observed in a developing organism.

Dewater: 1. Remove or separate a portion of the water in a sludge or slurry to dry the sludge so it can be handled and disposed of. 2. Remove or drain the water from a tank or trench.

Diatomaceous Earth (Diatomite): A chalk-like material (fossilized diatoms) used to filter out solid waste in wastewater treatment plants; also used as an active ingredient in some powdered pesticides.

Diazinon: An insecticide. In 1986, EPA banned its use in open areas such as sod farms and golf courses because it posed a danger to migratory birds. The ban did not apply to agricultural, home lawn or commercial establishment uses.

Dibenzofurans: A group of organic compounds, some of which are toxic.

Dicofol: A pesticide used on citrus fruits.

Diesel Oil: Fuel for diesel engines obtained from the distillation of petroleum. It is composed chiefly of aliphatic hydrocarbons. Its volatility is similar to that of gas oil. Its efficiency is measured by cetane number.

Diffuse Radiation: Solar radiation, scattered by water vapor, dust, and other particles as it passes through the atmosphere so that it appears to come from the entire sky. Diffuse radiation is higher on hazy or overcast days than on clear days.

Diffused Air: A type of aeration that forces oxygen into sewage by pumping air through perforated pipes inside a holding tank.

Diffusion: The movement of suspended or dissolved particles (or molecules) from a more concentrated to a less concentrated area. The process tends to distribute the particles or molecules more uniformly.

Digestate: The residue or "digested" waste produced by methane production from organic or biodegradable waste. Digestate is made up of excess bacteria, organic matter that has not broken down and mineralized matter. After treatment, it can be used as compost.

Digester: In wastewater treatment, a closed tank; in solid-waste conversion, a unit in which bacterial action is induced and accelerated in order to break down organic matter and establish the proper carbon to nitrogen ratio.

Digestion: The biochemical decomposition of organic matter, resulting in partial gasification, liquefaction, and mineralization of pollutants.

Dike: A low wall that can act as a barrier to prevent a spill from spreading.

Diluent: Any liquid or solid material used to dilute or carry an active ingredient.

Dilution Ratio: The relationship between the volume of water in a stream and the volume of incoming water. It affects the ability of the stream to assimilate waste.

Dimictic: Lakes and reservoirs that freeze over and normally go through two stratifications and two mixing cycles a year.

Dinocap: A fungicide used primarily by apple growers to control summer diseases. EPA proposed restrictions on its use in 1986 when laboratory tests found it caused birth defects in rabbits.

Dinoseb: A herbicide that is also used as a fungicide and insecticide. It was banned by EPA in 1986 because it posed the risk of birth defects and sterility.

Dioxin: Any of a family of compounds known chemically as dibenzo-p-dioxins. Concern about them arises from their potential toxicity as contaminants in commercial products. Tests on laboratory animals indicate that it is one of the more toxic anthropogenic (man-made) compounds.

Dioxins: The generic name of a family of chlorinated organic substances that are a byproduct of combustion processes. Dioxins are created by the combustion of products containing chlorine. Sources include cement plants, herbicide and pesticide manufacturing, paper pulp bleaching, foundries, metallurgy, steelmaking, waste incinerators, etc. They can also be produced by hard-to-evaluate natural sources such as forest fires and volcanic eruptions and by scattered sources such as open-air burning, i.e., garden, chimney and pit fires. Of the 210 existing dioxins, 17 are considered toxic.

Direct Access: The ability of a retail customer to purchase commodity electricity directly from the wholesale market rather than through a local distribution utility.

Direct Current (DC): Electricity that flows continuously in the same direction.

Direct Discharger: A municipal or industrial facility which introduces pollution through a defined conveyance or system such as outlet pipes; a point source.

Direct Energy Conversion: Production of electricity from an energy source without transferring the energy to a working fluid or steam. For example, photovoltaic cells transform light directly into electricity. Direct conversion systems have no moving parts and usually, produce direct current.

Direct Expansion (Refrigeration): Any system that, in operation between an environment where heat is absorbed (heat source), and an environment into which unwanted heat is directed (heat sink) at two different temperatures, is able to absorb heat from the heat source at the lower temperature and reject heat to the heat sink at the higher temperature. The cooling effect is obtained directly from a fluid called a refrigerant that absorbs heat at a low temperature and pressure, and transfers heat at a higher temperature and higher pressure.

Direct Filtration: A method of treating water which consists of the addition of coagulant chemicals, flash mixing, coagulation, minimal flocculation, and filtration. Sedimentation is not used.

Direct Push: Technology used for performing subsurface investigations by driving, pushing, and/or vibrating small-diameter hollow steel rods into the ground/ Also known as direct drive, drive point, or push technology.

Direct Radiation: Radiation that has traveled a straight path from the sun, as opposed to diffuse radiation.

Direct Runoff: Water that flows over the ground surface or through the ground directly into streams, rivers, and lakes.

Direct Solar Gain: Solar energy collected from the sun (as heat) in a building through windows, walls, skylights, etc.

Disaggregation: The functional separation of the vertically integrated utility into smaller, individually owned business units (i.e., generation, dispatch/control, transmission, distribution). The terms "de-integration," "disintegration" and "de-lamination" are sometimes used to mean the same thing.

Discharge: Flow of surface water in a stream or canal or the outflow of ground water from a flowing artesian well, ditch, or spring.

Disinfectant: A chemical or physical process that kills pathogenic organisms in water, air, or on surfaces. Chlorine is often used to disinfect sewage treatment effluent, water supplies, wells, and swimming pools.

Disinfectant By-Product: A compound formed by the reaction of a disinfectant such as chlorine with organic material in the water supply; a chemical by-product of the disinfection process.

Disinfectant Time: The time it takes water to move from the point of disinfectant application (or the previous point of residual disinfectant measurement) to a point before or at the point where the residual disinfectant is measured. In pipelines, the time is calculated by dividing the internal volume of the pipe by the maximum hourly flow rate; within mixing basins and storage reservoirs it is determined by tracer studies of an equivalent demonstration.

Dispatch: The operating control of an integrated electric system to: Assign generation to specific generating plants and other sources of supply to effect the most reliable and economical supply as the total of the significant area loads rises or falls. Control operations and maintenance of high-voltage lines, substations, and equipment, including administration of safety procedures. Operate the interconnection. Schedule energy transactions with other interconnected electric utilities.

Dispersant: A chemical agent used to break up concentrations of organic material such as spilled oil.

Displacement Savings: Saving realized by displacing purchases of natural gas or electricity from a local utility by using landfill gas for power and heat.

Disposables: Consumer products, other items, and packaging used once or a few times and discarded.

Disposal: Final placement or destruction of toxic, radioactive, or other wastes; surplus or banned pesticides or other chemicals; polluted soils; and drums containing hazardous materials from removal actions or accidental releases. Disposal may be accomplished through the use of approved secure landfills, surface impoundments, land farming, deep-well injection, ocean dumping, or incineration.

Disposal Facilities: Repositories for solid waste, including landfills and combustors intended for permanent containment or destruction of waste materials. Excludes transfer stations and composting facilities.

Disposal Fee: A fee charged for the amount of waste disposed of by customers at a landfill (also see Tipping Fee).

Dissolved Gas: Natural gas that can be developed for commercial use, and which is found mixed with oil in naturally occurring underground formations.

Dissolved Oxygen (DO): The oxygen freely available in water, vital to fish and other aquatic life and for the prevention of odors. DO levels are considered a most important indicator of a water body's ability to support desirable aquatic life. Secondary and advanced waste treatment is generally designed to ensure adequate DO in waste-receiving waters.

Dissolved Solids: Disintegrated organic and inorganic material in water. Excessive amounts make water unfit to drink or use in industrial processes.

Distillation: The act of purifying liquids through boiling, so that the steam or gaseous vapors condense to a pure liquid. Pollutants and contaminants may remain in a concentrated residue.

Distributed Generation: A distributed generation system involves small amounts of generation located on a utility's distribution system for the purpose of meeting local (substation level) peak loads and/or displacing the need to build additional (or upgrade) local distribution lines.

Distribution: The delivery of electricity to the retail customer's home or business through low voltage distribution lines.

Distribution System (Electric Utility): The substations, transformers, and lines that convey electricity from high-power transmission lines to ultimate consumers.

Distribution Utility: The regulated electric utility entity that constructs and maintains the distribution wires connecting the transmission grid to the final customer. The Disco can also perform other services such as aggregating customers, purchasing a power supply, and transmission services for customers, billing customers and reimbursing suppliers, and offering other regulated or non-regulated energy services to retail customers. The "wires" and "customer service" functions provided by a distribution utility could be split so that two totally separate entities are used to supply these two types of distribution services.

Disturbance: Any event or series of events that disrupt ecosystem, community, or population structure and alters the physical environment.

Diversion: 1. Use of part of a stream flow as water supply. 2. A channel with a supporting ridge on the lower side constructed across a slope to divert water at a non-erosive velocity to sites where it can be used and disposed of.

Diversion Rate: The percentage of waste materials diverted from traditional disposal such as landfilling or incineration to be recycled, composted, or re-used.

Divestiture: The stripping off of one utility function from the others by selling (spinning-off) or in some other way changing the ownership of the assets related to that function. Most commonly associated with spinning-off generation assets so they are no longer owned by the shareholders that own the transmission and distribution assets.

DNA Hybridization: Use of a segment of DNA, called a DNA probe, to identify its complementary DNA; used to detect specific genes.

Dobson Unit (DU): Units of ozone level measurement. measurement of ozone levels. If for example, 100 DU of ozone were brought to the earth's surface they would form a layer one millimeter thick. Ozone levels vary geographically, even in the absence of ozone depletion.

Dose: The amount of ionizing radiation energy absorbed per unit mass of irradiated material at a specific location, such as a part of a human body.

Dosimeter: An instrument to measure dosage; many so-called dosimeters actually measure exposure rather than dosage. Dosimetry is the process or technology of measuring and/or estimating dosage.

DOT Reportable Quantity: The quantity of a substance specified in a U.S. Department of Transportation regulation that triggers labeling, packaging and other requirements related to shipping such substances.

Down Cycling: The process of recycling in such a way those new products are of lesser economic value. An example would be turning nylon face fiber into park benches.

Downgradient: The direction that groundwater flows; similar to "downstream" for surface water.

Downstream: A term used in the petroleum industry referring to the refining, transportation and marketing side of the business.

Downstream Processors: Industries dependent on crop production (e.g. canneries and food processors).

Draft: 1. the act of drawing or removing water from a tank or reservoir. 2. The water which is drawn or removed.

Drainage: Improving the productivity of agricultural land by removing excess water from the soil by such means as ditches or subsurface drainage tiles.

Drainage Basin: The area of land that drains water, sediment, and dissolved materials to a common outlet at some point along a stream channel.

Drainage Well: A well drilled to carry excess water off agricultural fields. Because they act as a funnel from the surface to the groundwater below, drainage wells can contribute to groundwater pollution.

Drawdown: 1. The drop in the water table or level of water in the ground when water is being pumped from a well. 2. The amount of water used from a tank or reservoir. 3. The drop in the water level of a tank or reservoir.

Dredging: The removal of mud from the bottom of water bodies. This can disturb the ecosystem and causes silting that kills aquatic life. Dredging of contaminated mud can expose biota to heavy metals and other toxics. Dredging activities may be subject to regulation under Section 404 of the Clean Water Act.

Drilling Fluid: Fluid used to lubricate the bit and convey drill cuttings to the surface with rotary drilling equipment. Usually composed of bentonite slurry or muddy water. Can become contaminated, leading to cross contamination, and may require special disposal. Not used with DP methods

Drinking Water Equivalent Level: Protective level of exposure related to potentially non-carcinogenic effects of chemicals that are also known to cause cancer.

Drive Casing: Heavy duty steel casing is driven along with the sampling tool in cased DP systems. Keeps the hole open between sampling runs and is not removed until the last sample has been collected.

Drive Point Profiler: An exposed groundwater DP system used to collect multiple depth-discrete groundwater samples. Ports in the tip of the probe connected to an internal stainless steel or Teflon tube that extends to the surface. Samples are collected via suction or airlift methods. Deionized water is pumped down through the ports to prevent plugging while driving the tool to the next sampling depth.

Drop-off: Recyclable materials collection method in which individuals bring them to a designated collection site.

Dry Bulb Temperature: A measure of the sensible temperature of the air.

Dry Hole: A drilled well that does not yield gas and/or oil quantities or condition to support commercial production; also applied to gas that has been produced and from which liquid components have been removed.

Dual-Duct System: A central plant heating, ventilation and air conditioning (HVAC ) system that produces conditioned air at two temperatures and humidity levels. The air is then supplied through two independent duct systems to the points of usage where mixing occurs.

Dual-Fuel or Bi-Fuel Vehicle: Refers to a vehicle capable of operating on two different fuels, in distinct fuelling systems, such as compressed natural gas and gasoline.

Dual-Phase Extraction: Active withdrawal of both liquid and gas phases from a well usually involving the use of a vacuum pump.

Duct: A passageway made of sheet metal or other suitable material used for conveying air or other gas at relatively low pressures.

Dump: A site used to dispose of solid waste without environmental controls.

Dump: Excess hydropower that cannot be stored or conserved. Also, know as SPILL ENERGY.

Dumpster: A generic term used for front-load and rear-load containers.

Dustfall Jar: An open container used to collect large particles from the air for measurement and analysis.

Dynamometer: A device used to place a load on an engine and measure its performance.

Dystrophic Lakes: Acidic, shallow bodies of water that contain much humus and/or other organic matter; contain many plants but fish.

Eco-Design: Eco-design consists of building environmental protection into the design of assets and services. It leads to the manufacture and sale of products that are more environmentally friendly throughout their lifecycle, i.e., from the extraction of raw materials and the waste generated in the manufacturing process, to the use and ultimate disposal of the products.

Eco-Efficiency: The ability to produce and delivery desirable, competitively priced goods and services while progressively reducing the ecological impacts of these actions.

Ecological Entity: In ecological risk assessment, a general term referring to a species, a group of species, an ecosystem function or characteristic, or a specific habitat or biome.

Ecological/Environmental Sustainability: Maintenance of ecosystem components and functions for future generations.

Ecological Exposure: Exposure of a non-human organism to a stressor.

Ecological Footprint: The resulting impacts on the environment based on the choices we make (i.e., raw materials selection, energy selection, transportation, etc).

Ecological Impact: The effect that a man-caused or natural activity has on living organisms and their non-living (abiotic) environment.

Ecological Indicator: A characteristic of an ecosystem that is related to, or derived from, a measure of the biotic or a biotic variable, that can provide quantitative information on ecological structure and function. An indicator can contribute to a measure of integrity and sustainability.

Ecological Integrity: A living system exhibits integrity if, when subjected to disturbance, it sustains and organizes self-correcting ability to recover toward a biomass end-state that is normal for that system. End-states other than the pristine or naturally whole may be accepted as normal and good.

Ecological Risk Assessment: The application of a formal framework, analytical process, or model to estimate the effects of human actions(s) on a natural resource and to interpret the significance of those effects in light of the uncertainties identified in each component of the assessment process. Such analysis includes initial hazard identification, exposure and dose-response assessments, and risk characterization.

Ecology: The relationship of living things to one another and their environment, or the study of such relationships.

Economic Efficiency: A term that refers to the optimal production and consumption of goods and services. This generally occurs when prices of products and services reflect their marginal costs. Economic efficiency gains can be achieved through cost reduction, but it is better to think of the concept as actions that promote an increase in overall net value (which includes, but is not limited to, cost reductions).

Economic Poisons: Chemicals used to control pests and to defoliate cash crops such as cotton.

Economies of Sale: Economies of scale exist where the industry exhibits decreasing average long-run costs with size.

Economizer Air: A ducting arrangement and automatic control system that allows a heating, ventilation and air conditioning (HVAC) system to supply up to 100 percent outside air to satisfy cooling demands, even if additional mechanical cooling is required.

Economizer Water: A system which uses either direct evaporative cooling or a secondary evaporative cooling water loop and cooling coil to satisfy cooling loads, even if additional mechanical cooling is required.

Economy Energy (Electricity Utility): Electricity purchased by one utility from another to take the place of electricity that would have cost more to produce on the utility's own system.

Ecosphere: The "bio-bubble" that contains life on earth, in surface waters, and in the air.

Ecosystem: The interacting system of a biological community and its non-living environmental surroundings.

Ecosystem Structure: Attributes related to the instantaneous physical state of an ecosystem; examples include species population density, species richness or evenness, and standing crop biomass.

Ecotone: A habitat created by the juxtaposition of distinctly different habitats; an edge habitat; or an ecological zone or boundary where two or more ecosystems meet.

Edison Electric Institute (EEI): An association of electric companies formed in 1933 "to exchange information on industry developments and to act as an advocate for utilities on subjects of national interest."

Edison, Thomas Alva: The "father" of the American energy industry, Thomas Edison was an American inventor who was born in 1847 and died in 1931. He patented a total of 1,093 inventions - more than any other person in American history. Among the most important were the incandescent electric light bulb (1879), the phonograph (1877) and the movie projector (1893).

Efficacy, Lighting: The ratio of light from a lamp to the electrical power consumed, including ballast losses, expressed as lumens per watt.

Efficiency: The ratio of the useful energy delivered by a dynamic system (such as a machine, engine, or motor) to the energy supplied to it over the same period or cycle of operation. The ratio is usually determined under specific test conditions.

Effluent: Wastewater--treated or untreated--that flows out of a treatment plant, sewer, or industrial outfall. Generally, refers to wastes discharged into surface waters.

Effluent Guidelines: Technical EPA documents which set effluent limitations for given industries and pollutants.

Effluent Limitation: Restrictions established by a state or EPA on quantities, rates, and concentrations in wastewater discharges.

Ejector: A device used to disperse a chemical solution into water being treated.

Electric Capacity: The ability of a power plant to produce a given output of electric energy at an instant in time, measured in kilowatts or megawatts.

Electric Generator: A device that converts a heat, chemical or mechanical energy into electricity.

Electric Resistance Heater: A device that produces heat through electric resistance. For example, an electric current is run through a wire coil with a relatively high electric resistance, thereby converting the electric energy into heat which can be transferred to space by fans.

Electric Radiant Heating: A heating system in which electric resistance is used to produce heat which radiates to nearby surfaces. There is no fan component to a radiant heating system.

Electric Utility: Any person or state agency with a monopoly franchise (including any municipality), which sells electric energy to end-use customers; this term includes the Tennessee valley Authority, but does not include other Federal power marketing agency (from EP Act).

Electrical Efficiency: Electrical output in relation to fuel input.

Electricity: A property of the basic particles of matter. A form of energy having magnetic, radiant and chemical effects. Electric current is created by a flow of charged particles (electrons).

Electrodialysis: A process that uses electrical current applied to permeable membranes to remove minerals from water. Often used to desalinize salty or brackish water.

Electrolysis: Breaking a chemical compound down into its elements by passing a direct current through it. Electrolysis of water, for example, produces hydrogen and oxygen.

Electromagnetic Fields (EMF): Ordinary every day use of electricity produces magnetic and electric fields. These 60 Hertz fields (fields that go back and forth 60 times a second) are associated with electrical appliances, power lines and wiring in buildings.

Electromagnetic Geophysical Methods: Ways to measure subsurface conductivity via low-frequency electromagnetic induction.

Electrostatic Precipitator (ESP): A device that removes particles from a gas stream (smoke) after combustion occurs. The ESP imparts an electrical charge to the particles, causing them to adhere to metal plates inside the precipitator. Rapping on the plates causes the particles to fall into a hopper for disposal.

Element: A substance consisting entirely of atoms of the same atomic number.

Elevation: 1) The height above sea level (altitude); 2) A geometrical projection, such as a building, on a plane perpendicular to the horizon.

Eligible Costs: The construction costs for wastewater treatment works upon which EPA grants are based.

EMAP Data: Environmental monitoring data collected under the auspices of the Environmental Monitoring and Assessment Program. All EMAP data share the common attribute of being of known quality, having been collected in the context of explicit data quality objectives (DQOs) and a consistent quality assurance program.

Embedded Costs Exceeding Market Prices (ECEMP): Embedded costs of utility investments exceeding market prices are: i) costs incurred pursuant to a regulatory or contractual obligation; 2) costs that are reflected in cost-based rates, and 3) cost-based rates that exceed the price of alternatives in the marketplace. ECEMPS may become "stranded costs" where they exceed the amount that can be recovered through the asset's sale. Regulatory questions involve whether such costs should be recovered by utility shareholders and if so, how they should be recovered. "Transition costs" are stranded costs which are charged to utility customers through some type of fee or surcharge after the assets are sold or separated from the vertically-integrated utility. "Stranded assets" are assets which cannot be sold for some reason. The British nuclear plants are an example of stranded assets which no one would buy.

Embodied Energy: A combination of the energy required for the process to make a product and the molecular energy inherent in the product’s material content.

Embodied Mass: The total quantity of mass materials required to produce, recycle or dispose of raw materials and products.

Emergency and Hazardous Chemical Inventory: An annual report by facilities having one or more extremely hazardous substances or hazardous chemicals above certain weight limits.

Emergency (Chemical): A situation created by an accidental release or spill of hazardous chemicals that poses a threat to the safety of workers, residents, the environment, or property.

Emergency Core Cooling System (ECCS): Equipment designed to cool the core of a nuclear reactor in the event of a complete loss of the coolant.

Emergency Exemption: Provision in FIFRA under which EPA can grant a temporary exemption to a state or another federal agency to allow the use of a pesticide product not registered for that particular use. Such actions involve unanticipated and/or severe pest problems where there is not a time or interest by a manufacturer to register the product for that use. (Registrants cannot apply for such exemptions.)

Emergency Removal Action: 1. Steps take to remove contaminated materials that pose imminent threats to local residents (e.g. removal of leaking drums or the excavation of explosive waste.) 2. The state record of such removals.

Emergency Response Values: Concentrations of chemicals, published by various groups, defining acceptable levels for short-term exposures in emergencies.

Emergency Suspension: Suspension of a pesticide product registration due to an imminent hazard. The action immediately halts distribution, sale, and sometimes actual use of the pesticide involved.

Emission: Pollution discharged into the atmosphere from smokestacks, other vents, and surface areas of commercial or industrial facilities; from residential chimneys; and from a motor vehicle, locomotive, or aircraft exhausts.

Emission Cap: A limit designed to prevent projected growth in emissions from existing and future stationary sources from eroding any mandated reductions. Generally, such provisions require that any emission growth from facilities under the restrictions be offset by equivalent reductions at other facilities under the same cap.

Emission Control Equipment (Wheelabrator): A category of equipment used at waste-to-energy facilities to meet emission standards and generate reports required by agency regulators.

Emission Factor: The relationship between the amount of pollution produced and the amount of raw material processed. For example, an emission factor for a blast furnace making iron would be the number of pounds of particulates per ton of raw materials.

Emission Inventory: A listing, by source, of a number of air pollutants discharged into the atmosphere of a community; used to establish emission standards.

Emission Standard: The maximum amount of air polluting discharge legally allowed from a single source, mobile or stationary.

Emissions Trading: The creation of surplus emission reductions at certain stacks, vents or similar emissions sources and the use of this surplus to meet or redefine pollution requirements applicable to other emissions sources. This allows one source to increase emissions when another source reduces them, maintaining an overall constant emission level. Facilities that reduce emissions substantially may "bank" their "credits" or sell them to other facilities or industries.

Emissivity: The property of emitting radiation; possessed by all materials to a varying extent.

Emittance: The emissivity of a material, expressed as a fraction. Emittance values range from 0.05 for brightly polished metals to 0.96 for flat black paint.

Emulsifier: A chemical that aids in suspending one liquid in another. Usually, it is an organic chemical in an aqueous solution.

Encapsulation: The treatment of the asbestos-containing material with a liquid that covers the surface with a protective coating or embeds fibers in an adhesive matrix to prevent their release into the air.

Enclosure: Putting an airtight, impermeable, permanent barrier around asbestos-containing materials to prevent the release of asbestos fibers into the air.

End User: Consumer of products for the purpose of recycling. It excludes products for re-use or combustion for energy recovery.

End-of-the-pipe: Technologies such as scrubbers on smokestacks and catalytic convertors on automobile tailpipes that reduce emissions of pollutants after they have formed.

End-use Product: A pesticide formulation for field or other end use. The label has instructions for use or application to control pests or regulate plant growth. The term excludes products used to formulate other pesticide products.

Endangered Species: Animals, birds, fish, plants, or other living organisms threatened with extinction by anthropogenic (man-caused) or other natural changes in their environment. Requirements for declaring a species endangered are contained in the Endangered Species Act.

Endangerment Assessment: A study to determine the nature and extent of contamination at a site on the National Priorities List and the risks posed to public health or the environment. EPA or the state conducts the study when a legal action is to be taken to direct potentially responsible parties to clean up a site or pay for it. An endangerment assessment supplements a remedial investigation.

Endrin: A pesticide toxic to freshwater and marine aquatic life that produces adverse health effects in domestic water supplies.

Energy: The capacity for doing work. Forms of energy include: thermal, mechanical, electrical and chemical. Energy may be transformed from one form into another.

Energy Budget: A requirement in the Building Energy Efficiency Standards that a proposed building be designed to consume no more than a specified number of British thermal units (Btus) per year per square foot of conditioned floor area.

Energy Charge: The amount of money owed by an electric customer for kilowatt-hours consumed.

Energy Consumption: The amount of energy consumed in the form in which it is acquired by the user. The term excludes electrical generation and distribution losses.

Energy Efficiency: Using less energy/electricity to perform the same function. Programs designed to use electricity more efficiently - doing the same with less. For the purpose of this paper, energy efficiency is distinguished from DSM programs in that the latter are utility-sponsored and -financed, while the former is a broader term not limited to any particular sponsor or funding source. "Energy conservation" is a term which has also been used but it has the connotation of doing without in order to save energy rather than using less energy to do the something and so is not used as much today. Many people use these terms interchangeably.

Energy Efficiency Ratio (EER): The ratio of cooling capacity of an air conditioning unit in Btu’s per hour to the total electrical input in watts under specified test conditions.

Energy/Fuel Diversity: Policy that encourages the development of energy technologies to diversify energy supply sources, thus reducing reliance on conventional (petroleum) fuels; applies to all energy sectors.

Energy From waste: Energy recovery of post-recycling waste residue - an alternative to landfill.

Energy Management System: A control system capable of monitoring environmental and system loads and adjusting HVAC operations accordingly in order to conserve energy while maintaining comfort.

Energy Policy Act of 2005 (EPAct05): A comprehensive federal energy law that provided important incentives to renewable energy producers, including waste-to-energy facilities.

Energy Recovery: Obtaining energy from waste through a variety of processes (e.g. combustion).

Energy Recovery: Waste contains energy in the form of calories, which are released by burning and recovered to produce electricity and/or heat and/or steam. This can then be used, for example, for heating buildings. Because of its energy potential, landfill gas is also recovered for heat, steam or electricity production, cogeneration (combined production of electricity and heat), conversion to vehicle fuel, or reinjection into the gas distribution network.

Energy Reserves: The portion of total energy resources that is known and can be recovered with presently available technology at an affordable cost.

Energy Resources: Everything that could be used by society as a source of energy.

Energy Security/Fuel Security: Policy that considers the risk of dependence on fuel sources located in remote and unstable regions of the world and the benefits of domestic and diverse fuel sources.

Energy vs. Capacity: If you’re filling up a bucket with water from a garden hose, the amount of water moving through the hose is the “energy” or wattage, and the water pressure inside the hose is the voltage. The size of the hose is the capacity.

Engineered Controls: Method of managing environmental and health risks by placing a barrier between the contamination and the rest of the site, thus limiting exposure pathways.

Enrichment: The addition of nutrients (e.g. nitrogen, phosphorus, carbon compounds) from sewage effluent or agricultural runoff to surface water, greatly increases the growth potential for algae and other aquatic plants.

Enthalpy: The quantity of heat necessary to raise the temperature of a substance from one point to a higher temperature. The quantity of heat includes both latent and sensible.

Entitlement: Electric energy or generating capacity that a utility has a right to access under power exchange or sales agreements.

Entrain: To trap bubbles in water either mechanically through turbulence or chemically through a reaction.

Environment: The sum of all external conditions affecting the life, development, and survival of an organism.

Environmental Cost: The monetary impact from the negative environmental effects resulting from the choices we make.

Environmental/Ecological Risk: The potential for adverse effects on living organisms associated with pollution of the environment by effluents, emissions, wastes, or accidental chemical releases; energy use; or the depletion of natural resources.

Environmental Exposure: Human exposure to pollutants originating from facility emissions. Threshold levels are not necessarily surpassed, but low-level chronic pollutant exposure is one of the most common forms of environmental exposure.

Environmental Fate: The destiny of a chemical or biological pollutant after release into the environment.

Environmental Fate Data: Data that characterize a pesticide's fate in the ecosystem, considering factors that foster its degradation (light, water, microbes), pathways and resultant products.

Environmental Impact Assessment (EIA): An evaluation designed to identify and predict the impact of an action or a project on the environment and human health and well-being. Can include risk assessment as a component, along with economic and land use assessment.

Environmental Indicator: A measurement, statistic or value that provides a proximate gauge or evidence of the effects of environmental management programs or of the state or condition of the environment.

Environmental Movement Systems (EMS): Series of activities to monitor and manage the environmental impacts of manufacturing activities. (Example: ISO 14001).

Environmental Protection Agency, The (EPA): A federal agency charged with protecting the environment. A federal agency created in 1970 to permit coordinated governmental action for protection of the environment by systematic abatement and control of pollution through integration or research, monitoring, standards setting and enforcement activities.

Environmental Risk Assessment (EnRA): An evaluation of the interactions of agents, humans, and ecological resources. Comprised of human health risk assessment and ecological risk assessment, typically evaluating the probabilities and magnitudes of harm that could come from environmental contaminants.

Environmental Site Assessment: The process of determining whether contamination is present on a parcel of real property.

Environmental Sustainability: Long-term maintenance of ecosystem components and functions for future generations.

Environmentally Friendly: A generic statement often used to designate a product or process that has a reduced ecological footprint when compared to other products/processes.

Environmentally Preferable: Products, services or systems that have a lesser or reduced effect on human health and the environment when compared with competing products, services or systems that serve the same purpose.

EP Act: The Energy Policy Act of 1992 addresses a wide variety of energy issues. The legislation creates a new class of power generators, exempt wholesale generators (EWGs), that are exempt from the provisions of the Public Utilities Holding Company Act of 1935 and grants the authority to FERC to order and condition access by eligible parties to the interconnected transmission grid.

Epidemiology: Study of the distribution of disease, or other health-related states and events in human populations, as related to age, sex, occupation, ethnicity, and economic status in order to identify and alleviate health problems and promote better health.

Epilimnion: Upper waters of a thermally stratified lake subject to wind action.

Episode (Pollution): An air pollution incident in a given area caused by a concentration of atmospheric pollutants under meteorological conditions that may result in a significant increase in illnesses or deaths. May also describe water pollution events or hazardous material spills.

Equilibrium: In relation to radiation, the state at which the radioactivity of consecutive elements within a radioactive series is neither increasing nor decreasing.

Equivalent Method: Any method of sampling and analyzing for air pollution which has been demonstrated to the EPA Administrator's satisfaction to be, under specific conditions, an acceptable alternative to normally used reference methods.

Erosion: The wearing away of land surface by wind or water, intensified by land-clearing practices related to farming, residential or industrial development, road building, or logging.

ESCO - Efficiency Service Company: A company that offers to reduce a client's electricity consumption with the cost savings being split with the client.

Estuary: Region of interaction between rivers and near-shore ocean waters, where tidal action and river flow mix fresh and salt water. Such areas include bays, mouths of rivers, salt marshes, and lagoons. These brackish water ecosystems shelter and feed marine life, birds, and wildlife.

Ethanol: An alternative automotive fuel derived from grain and corn; usually blended with gasoline to form gasohol.

Ethanol (also known as Ethyl Alcohol or Grain Alcohol, CH3CH2OH): A liquid that is produced chemically from ethylene or biologically from the fermentation of various sugars from carbohydrates found in agricultural crops and cellulosic residues from crops or wood. Used in the United States as a gasoline octane enhancer and oxygenate, it increases octane 2.5 to 3.0 numbers at 10 percent concentration. Ethanol can also be used in higher concentration (E85) in vehicles optimized for its use.

Ethyl Tertiary Butyl Ether (ETBE): An aliphatic ether similar to MTBE. This fuel oxygenate is manufactured by reacting isobutylene with ethanol. Having high octane and low volatility characteristics, ETBE can be added to gasoline up to a level of approximately 17 percent by volume. ETBE is used as an oxygenate in some reformulated gasoline.

Ethylene: A colorless gas that burns and is an oil refinery product.

Ethylene Dibromide (EDB): A chemical used as an agricultural fumigant and in certain industrial processes. Extremely toxic and found to be a carcinogen in laboratory animals, EDB has been banned for most agricultural uses in the United States.

Eutrophic Lakes: Shallow, murky bodies of water with concentrations of plant nutrients causing excessive production of algae.

Eutrophication: The slow aging process during which a lake, estuary, or bay evolves into a bog or marsh and eventually disappears. During the later stages of eutrophication, the water body is choked by abundant plant life due to higher levels of nutritive compounds such as nitrogen and phosphorus. Human activities can accelerate the process.

EV (Electric Vehicle): A vehicle powered by electricity, usually provided by batteries but may also be provided by photovoltaic (solar) cells or a fuel cell.

Evaporation Ponds: Areas where sewage sludge is dumped and dried.

Evaporative Cooling: Cooling by exchange of latent heat from water sprays, jets of water, or wetted material.

Evapotranspiration: The loss of water from the soil both by evaporation and by transpiration from the plants growing in the soil.

Exceedance: Violation of the pollutant levels permitted by environmental protection standards.

Exceptional Method: An approved alternative calculation method that analyzes designs, materials, or devices that cannot be adequately modeled using public domain computer programs.

Exchange (Electric Utility): Agreements between utilities providing for purchase, sale, and trading of power. Usually, relates to capacity (kilowatts) but sometimes energy (kilowatt-hours)

Exclusion: In the asbestos program, one of several situations that permit a Local Education Agency (LEA) to delete one or more of the items required by the Asbestos Hazard Emergency Response Act (AHERA); e.g. records of previous asbestos sample collection and analysis may be used by the accredited inspector in lieu of AHERA bulk sampling.

Exclusionary Ordinance: Zoning that excludes classes of persons or businesses from a particular neighborhood or area.

Exempt Wholesale Generator (EWG): Created under the 1992 Energy Policy Act, these wholesale generators are exempt from certain financial and legal restrictions stipulated in the Public Utilities Holding Company Act of 1935.

Exfiltration: Air flows outward through a wall, building envelope, etc.

Exhaust: Air removed deliberately from a space, by a fan or other means, usually to remove contaminants from a location near their source.

Exotic Species: A species that is not indigenous to a region.

Expansion Unit: The installation of a new boiler at an existing waste-to-energy facility, which increases the waste processing and energy generating capacity at the facility.

Experimental Use Permit: Obtained by manufacturers for testing new pesticides or uses thereof

Explosive Limits: The amounts of vapor in the air that form explosive mixtures; limits are expressed as lower and upper limits and give the range of vapor concentrations in air that will explode if an ignition source is present.

Exports : In the solid waste program, municipal solid waste and recyclables transported outside the state or locality where they originated.

Exports (Electric Utility): Power capacity or energy that a utility is required by contract to supply outside of its own service area and not covered by general rate schedules.

Exposure: The amount of radiation or pollutant present in a given environment that represents a potential health threat to living organisms.

Exposure Assessment: Identifying the pathways by which toxicants may reach individuals, estimating how much of a chemical an individual is likely to be exposed to, and estimating the number likely to be exposed.

Exposure Concentration: The concentration of a chemical or other pollutant representing a health threat in a given environment.

Exposure Indicator: A characteristic of the environment measured to provide evidence of the occurrence or magnitude of a response indicator's exposure to a chemical or biological stress.

Exposure Level: The amount (concentration) of a chemical at the absorptive surfaces of an organism.

Exposure Pathway: The path from sources of pollutants via, soil, water, or food to man and other species or settings.

Exposure Route: The way a chemical or pollutant enters an organism after contact; i.e. by ingestion, inhalation, or dermal absorption.

Exposure-Response Relationship: The relationship between exposure level and the incidence of adverse effects.

Extra High Voltage (EHV): Voltage levels higher than those normally used on transmission lines. Generally, EHV is considered to be 345,000 volts or higher.

Extraction Procedure (EP Toxic): Determining toxicity by a procedure which simulates leaching; if a certain concentration of a toxic substance can be leached from a waste, that waste is considered hazardous, i.e."EP Toxic."

Extraction Well: A discharge well used to remove groundwater or air.

Fabric Filter: A cloth device that catches dust particles from industrial emissions.

Facility Management: The provision of this service involves the management of all general and technical services for an industrial or service site.

Facultative Bacteria: Bacteria that can live under aerobic or anaerobic conditions.

Fahrenheit: A temperature scale in which the boiling point of water is 212 degrees and its freezing point is 32 degrees. To convert Fahrenheit to Celsius, subtract 32, multiply by 5, and divide the product by 9. For example: 100 degrees Fahrenheit - 32 = 68; 68 x 5 = 340; 340 / 9 = 37.77 degrees Celsius.

Fan Coil: A component of a heating, ventilation and air conditioning (HVAC) system containing a fan and heating or cooling coil, used to distribute heated or cooled air.

Feasibility Study: 1. Analysis of the practicability of a proposal; e.g., a description and analysis of potential cleanup alternatives for a site such as one on the National Priorities List. The feasibility study usually recommends selection of a cost-effective alternative. It usually starts as soon as the remedial investigation is underway; together, they are commonly referred to as the "RI/FS". 2. A small-scale investigation of a problem to ascertain whether a proposed research approach is likely to provide useful data.

Fecal Coliform Bacteria: Bacteria found in the intestinal tracts of mammals. Their presence in water or sludge is an indicator of pollution and possible contamination by pathogens.

Federal Emergency Management Agency (FEMA): The federal agency in charge of disaster recovery in locations that have been declared disaster areas by a state's Governor and the President of the United States.

Federal Energy Regulatory Commission (FERC): An independent regulatory commission within the U.S. Department of Energy that has jurisdiction over energy producers that sell or transport fuels for resale in interstate commerce; the authority to set oil and gas pipeline transportation rates and to set the value of oil and gas pipelines for rate making purposes; and regulates wholesale electric rates and hydroelectric plant licenses.

Federal Implementation Plan: Under current law, a federally implemented plan to achieve attainment of air quality standards, used when a state is unable to develop an adequate plan.

Federal Motor Vehicle Control Program: All federal actions aimed at controlling pollution from motor vehicles by such efforts as establishing and enforcing tailpipe and evaporative emission standards for new vehicles, testing methods development, and guidance to states operating inspection and maintenance programs. The federally designated area that is required to meet and maintain federal ambient air quality standards. May include nearby locations in the same state or nearby states that share common air pollution problems.

Feedlot: A confined area for the controlled feeding of animals. Tends to concentrate large amounts of animal waste that cannot be absorbed by the soil and, hence, may be carried to nearby streams or lakes by rainfall runoff.

Fen: A type of wetland that accumulates peat deposits. Fens are less acidic than bogs, deriving most of their water from groundwater rich in calcium and magnesium.

Ferrous Metals: Magnetic metals derived from iron or steel; products made from ferrous metals include appliances, furniture, containers, and packagings like steel drums and barrels. Recycled products include processing tin/steel cans, strapping, and metals from appliances into new products.

Fill: Man-made deposits of natural soils or rock products and waste materials.

Filling: Depositing dirt, mud or other materials into aquatic areas to create more dry land, usually for agricultural or commercial development purposes, often with ruinous ecological consequences.

Filter Strip: Strip or area of vegetation used for removing sediment, organic matter, and other pollutants from runoff and wastewater.

Filtration: A treatment process, under the control of qualified operators, for removing solid (particulate) matter from water by means of porous media such as sand or a man-made filter; often used to remove particles that contain pathogens.

Financial Assurance for Closure: Documentation or proof that an owner or operator of a facility such as a landfill or other waste repository is capable of paying the projected costs of closing the facility and monitoring it afterward as provided in RCRA regulations.

Finished Water: Water is "finished" when it has passed through all the processes in a water treatment plant and is ready to be delivered to consumers.

Firm Energy: Power supplies that are guaranteed to be delivered under terms defined by contract.

First Draw: The water that comes out when a tap is first opened, likely to have the highest level of lead contamination from plumbing materials.

Fission: A release of energy caused by the splitting of an atom's nucleus. This is the energy process used in conventional nuclear power plants to make the heat needed to run steam electric turbines.

Fissionable Material: A substance whose atoms can be split by slow neutrons. Uranium-235, plutonium-239 and uranium-233 are fissionable materials.

Fix a Sample: A sample is "fixed" in the field by adding chemicals that prevent water quality indicators of interest in the sample from changing before laboratory measurements are made.

Fixed-Location Monitoring: Sampling of an environmental or ambient medium for pollutant concentration at one location continuously or repeatedly.

Flammable: Any material that ignites easily and will burn rapidly.

Flare: A control device that burns hazardous materials to prevent their release into the environment; may operate continuously or intermittently, usually on top of a stack.

Flare Gas: Unwanted natural gas that is disposed of by burning as it is released from an oil field.

Flare Tower: A structure resembling a high chimney used for burning off petroleum by-products.

Flaring: The burning of methane emitted from collection pipes at a landfill.

Flash Point: The lowest temperature at which evaporation of a substance produces sufficient vapor to form an ignitable mixture with air.

Flat Plate: A device used to collect solar energy. It is a piece of metal painted black on the side facing the sun, to absorb the sun's heat.

Flexible Fuel Vehicle (FFV): A vehicle that can operate on either alcohol fuels (methanol or ethanol) or regular unleaded gasoline or any combination of the two from the same tank.

Floc: A clump of solids formed in sewage by biological or chemical action.

Flocculation: Process by which clumps of solids in water or sewage aggregate through biological or chemical action so they can be separated from water or sewage.

Floodplain: The flat or nearly flat land along a river or stream or in a tidal area that is covered by water during a flood.

Floor Sweep: Capture of heavier-than-air gasses that collect at floor level.

Flow Rate: The rate, expressed in gallons -or liters-per-hour, at which a fluid escapes from a hole or fissure in a tank. Such measurements are also made of liquid waste, effluent, and surface water movement.

Flowable: Pesticide and other formulations in which the active ingredients are finely ground insoluble solids suspended in a liquid. They are mixed with water for application.

Flowmeter: A gauge indicating the velocity of wastewater moving through a treatment plant or of any liquid moving through various industrial processes.

Flue Gas: The air coming out of a chimney after combustion in the burner it is venting. It can include nitrogen oxides, carbon oxides, water vapor, sulfur oxides, particles and many chemical pollutants.

Flue Gas Desulfurization: A technology that employs a sorbent, usually lime or limestone, to remove sulfur dioxide from the gasses produced by burning fossil fuels. Flue gas desulfurization is current state-of-the-art technology for major SO2 emitters, like power plants.

Flue Gas Treatment Residues: Incineration of municipal waste produces flue gasses that are chemically treated to reduce pollution. They become solid residues able to be collected. The treatment combines neutralization and filtration and can purify over 98% of municipal waste incineration flue gasses. Targeted pollutants include acid gasses and particulate matter, heavy metals, nitrogen oxides, and dioxins, which are treated using supplementary processes. Flue gas treatment residues that consist primarily of fly ash are stabilized before being disposed of in hazardous waste landfills.

Fluidized: A mass of solid particles that is made to flow like a liquid by injection of water or gas is said to have been fluidized. In water treatment, a bed of filter media is fluidized by backwashing water through the filter.

Fluidized Bed Combustion: A process for burning powdered coal that is poured in a liquid-like stream with air or gasses. The process reduces sulfur dioxide emissions from coal combustion.

Fluidized Bed Incinerator: An incinerator that uses a bed of hot sand or other granular material to transfer heat directly to waste. Used mainly for destroying municipal sludge.

Fluidized-Bed Incinerator: A type of incinerator in which the stoker grate is replaced by a bed of limestone or sand that can withstand high temperatures. The heating of the bed and the high air velocities used to cause the bed to bubble, which gives rise to the term fluidized.

Flume: A natural or man-made channel that diverts water.

Fluorescent Lamp: A tubular electric lamp that is coated on its inner surface with a phosphor and that contains mercury vapor whose bombardment by electrons from the cathode provides ultraviolet light which causes the phosphor to emit visible light either of a selected color or closely approximating daylight.

Fluoridation: The addition of a chemical to increase the concentration of fluoride ions in drinking water to reduce the incidence of tooth decay.

Fluorides: Gaseous, solid, or dissolved compounds containing fluorine that result from industrial processes. Excessive amounts of food can lead to fluorosis.

Fluorocarbons (FCs): Any of a number of organic compounds analogous to hydrocarbons in which one or more hydrogen atoms are replaced by fluorine. Once used in the United States as a propellant for domestic aerosols, they are now found mainly in coolants and some industrial processes. FCs containing chlorine are called chlorofluorocarbons (CFCs). They are believed to be modifying the ozone layer in the stratosphere, thereby allowing more harmful solar radiation to reach the Earth's surface.

Fluorocarbon: Non-flammable, heat-stable hydrocarbon liquid or gas, in which some or all hydrogen atoms have been replaced by fluorine atoms. As with CFC’s, fluorocarbons, traditionally used as propellants (spray cans), are classified as ozone-depleting substances.

Fluorocarbon Gases: Propellants used in aerosol products and refrigerants that are believed to be causing depletion of the earth's ozone shield.

Flush: 1. To open a cold-water tap to clear out all the water which may have been sitting for a long time in the pipes. In new homes, to flush a system means to send large volumes of water gushing through the unused pipes to remove loose particles of solder and flux. 2. To force large amounts of water through a system to clean out piping or tubing, and storage or process tanks.

Flux: 1. A flowing or flow. 2. A substance used to help metals fuse together.

Fly Ash: Non-combustible residual particles expelled by flue gas.

Fly Ash: Fine, non-combustible particulate primarily resulting from the combustion of coal in furnaces and kilns. Often used as a filler material in concrete to displace virgin raw materials.

Fogging: Applying a pesticide by rapidly heating the liquid chemical so that it forms very fine droplets that resemble smoke or fog. It is used to destroy mosquitoes, black flies, and similar pests.

Food Chain: A sequence of organisms, each of which uses the next, lower member of the sequence as a food source.

Food Processing Waste: Food residues produced during agricultural and industrial operations.

Food Waste: Uneaten food and food preparation wastes from residences and commercial establishments such as grocery stores, restaurants, and produce stands, institutional cafeterias and kitchens, and industrial sources like employee lunchrooms.

Food Web: The feeding relationships by which energy and nutrients are transferred from one species to another.

Footcandle: A unit of illuminance on a surface that is one foot from a uniform point source of light of one candle and is equal to one lumen per square foot.

Forced Air Unit (FAU): A central furnace equipped with a fan or blower that provides the primary means for circulation of air.

Formaldehyde: A colorless, pungent, and irritating gas, CH20, used chiefly as a disinfectant and preservative and in synthesizing other compounds like resins.

Formulation: The substances comprising all active and inert ingredients in a pesticide.

Fossil Fuel: Fuel derived from ancient organic remains; e.g. peat, coal, crude oil, and natural gas.

Fossil Fuels: Coal, Oil, and Gas are called "fossil fuels" because they have been formed from the fossilized remains of prehistoric plants and animals. They provide around 66% of the world's electrical power, and 95% of the world's total energy demands (including heating, transport, electricity generation and other uses).

Fractional Distillation: The process of refining crude oil into various oil products. The various products are separated out in the order of their boiling points.

Fracture: A break in a rock formation due to structural stresses; e.g. faults, shears, joints, and planes of fracture cleavage.

Free Product: A petroleum hydrocarbon in the liquid free or nonaqueous phase.

Freeboard: 1. The vertical distance from the normal water surface to the top of a confining wall. 2. The vertical distance from the sand surface to the underside of a trough in a sand filter.

Fresh Water: Water that generally contains less than 1,000 milligrams-per-litre of dissolved solids.

Frequency: The number of cycles which an alternating current moves through in each second. Standard electric utility frequency in the United States is 60 cycles per second or 60 Hertz.

Frequency: Much like radio signals, electric generators can be “tuned” to produce power that vibrates at different frequencies. In the United States, virtually all electricity is generated and transmitted at 60-hertz or 60 cycles. Motors and other electrical equipment in the U.S. are calibrated to run at 60Hz. As the frequency fluctuates, it can damage all manner of electrical equipment. Frequency can be affected by a variety of factors and must be monitored closely to make sure it doesn’t fluctuate.

Friable: Capable of being crumbled, pulverized, or reduced to powder by hand pressure.

Friable Asbestos: Any material containing more than one-percent asbestos, and that can be crumbled or reduced to powder by hand pressure (May include previously non-friable material which becomes broken or damaged by mechanical force).

Fuel: A substance that can be used to produce heat.

Fuel Cell: A device or an electrochemical engine with no moving parts that converts the chemical energy of a fuel, such as a hydrogen, and an oxidant, such as oxygen, directly into electricity. The principal components of a fuel cell are catalytically activated electrodes for the fuel (anode) and the oxidant (cathode) and an electrolyte to conduct ions between the two electrodes, thus producing electricity.

Fuel Economy Standard: The Corporate Average Fuel Economy Standard (CAFE) effective in 1978. It enhanced the national fuel conservation effort imposing a miles-per-gallon floor for motor vehicles.

Fuel Efficiency: The proportion of energy released by fuel combustion that is converted into useful energy.

Fuel Gas: Synthetic gas used for heating or cooling. It has less energy content than pipeline-quality gas.

Fuel Oil: Petroleum products that are burned to produce heat or power.

Fuel Reprocessing (Nuclear): The means for obtaining usable, fissionable material from spent reactor fuel.

Fuel Rod (Nuclear): A long slender tube that holds fissionable material (fuel) for nuclear reactor use. Fuel rods are assembled into bundles called fuel elements or assemblies, which are loaded individually into the reactor core.

Fuel Switching: 1. A precombustion process whereby a low-sulfur coal is used in place of a higher sulfur coal in a power plant to reduce sulfur dioxide emissions. 2. Illegally using leaded gasoline in a motor vehicle designed to use only unleaded.

Fugitive Emissions: Emissions not caught by a capture system.

Fume: Tiny particles trapped in vapor in a gas stream.

Fumigant: A pesticide vaporized to kill pests. Used in buildings and greenhouses.

Functional Equivalent: Term used to describe EPA's decision-making process and its relationship to the environmental review conducted under the National Environmental Policy Act (NEPA). A review is considered functionally equivalent when it addresses the substantive components of a NEPA review.

Fungi: Typically filamentous, eukaryotic, nonchlorophyllic microorganisms. Fungi grow on dead or dying organic matter and may also grow on some building materials where excess moisture is present. Fungi can cause pungent odors, unsightly stains, and premature bio-deterioration of interior furnishings.

Fungicide: Pesticides which are used to control, deter, or destroy fungi.

Fungistat: A chemical that keeps fungi from growing.

Fungus (Fungi): Molds, mildews, yeasts, mushrooms, and puffballs, a group of organisms lacking in chlorophyll (i.e. are not photosynthetic) and which are usually non-mobile, filamentous, and multi-cellular. Some grow in soil; others attach themselves to decaying trees and other plants whence they obtain nutrients. Some are pathogens; others stabilize sewage and digest composted waste.

Furnace: This is the base of the incinerator, which is designed and built according to the volume and type of waste to be treated.

Furrow Irrigation: Irrigation method in which water travels through the field by means of small channels between each group of rows.

Fusion Energy: A power source, now under development, based on the release of energy that occurs when atoms are combined under the most extreme heat and pressure. It is the energy process of the sun and the stars.

Future Liability: Refers to potentially responsible parties' obligations to pay for additional response activities beyond those specified in the Record of Decision or Consent Decree.

Gallon: A unit of volume. A U.S. gallon has 231 cubic inches or 3.785 liters.

Garbage: Animal and vegetable waste resulting from the handling, storage, sale, preparation, cooking, and serving of foods.

Gas: Gaseous fuel (usually natural gas) that is burned to produce heat energy. The word also is used, colloquially, to refer to gasoline.

Gas Chromatograph/Mass Spectrometer: Instrument that identifies the molecular composition and concentrations of various chemicals in water and soil samples.

Gas Synthesis: A method producing synthetic gas from coal. It is also called the FISCHER-TROPSCH PROCESS.

Gas Utility: Any person engaged in, or authorized to engage in, distributing or transporting natural gas, including, but not limited to, any such person who is subject to the regulation of the Public Utilities Commission.

Gasification: Breakdown of hydrocarbons into a syngas by carefully controlling the amount of oxygen present.

Gasification: The process where biomass fuel is reacted with sub- stoichiometric quantities of air and oxygen usually under high pressure and temperature along with moisture to produce gas which contains hydrogen, methane, carbon monoxide, nitrogen, water and carbon dioxide. The gas can be burned directly in a boiler, or scrubbed and combusted in an engine-generator to produce electricity. The three types of gasification technologies available for biomass fuels are the fixed bed updraft, fixed bed downdraft, and fluidized bed gasifiers. Gasification is also the production of synthetic gas from coal.

Gasohol: Mixture of gasoline and ethanol derived from fermented agricultural products containing at least nine percent ethanol. Gasohol emissions contain less carbon monoxide than those from gasoline.

Gasoline: A light petroleum product obtained by refining oil, and used as motor vehicle fuel.

Gasoline Volatility: The property of gasoline whereby it evaporates into a vapor. Gasoline vapor is a mixture of volatile organic compounds.

Gatehouse: A gatehouse is found in a landfill or a transfer station. All incoming vehicles must stop to be processed and weighed, and all outgoing vehicles must stop to be weighed and receive a disposal ticket for charges.

General Lighting: Lighting designed to provide a substantially uniform level of illumination throughout an area, exclusive of any provision for special visual tasks or decorative effects.

Generating Station: A power plant.

Generation Company (GENCO): A regulated or non-regulated entity (depending upon the industry structure) that operates and maintains existing generating plants. The Genco may own the generation plants or interact with the short-term market on behalf of plant owners. In the context of restructuring the market for electricity, Genco is sometimes used to describe a specialized "marketer" for the generating plants formerly owned by a vertically-integrated utility.

Generation Dispatch and Control: Aggregating and dispatching (sending off to some location) generation from various generating facilities, providing backups and reliability services. Ancillary services include the provision of reactive power, frequency control, and load following.

Generator: 1. A facility or mobile source that emits pollutants into the air or releases hazardous waste into water or soil. 2. Any person, by site, whose act or process produces regulated medical waste or whose act first causes such waste to become subject to regulation. Where more than one person (e.g. doctors with separate medical practices) are located in the same building, each business entity is a separate generator.

Geothermal Element: An element of a county general plan consisting of a statement of geothermal development policies, including a diagram or diagrams and text setting forth objectives, principles, standards, and plan proposals, including a discussion of environmental damages and identification of sensitive environmental areas, including unique wildlife habitat, scenic, residential, and recreational areas, adopted pursuant to Section 65303 of the Government Code.

Geothermal Energy: Natural heat from within the earth, captured for production of electric power, space heating or industrial steam.

Geothermal Gradient: The change in the earth's temperature with depth. As one goes deeper, the earth becomes hotter.

Geothermal Steam: Steam drawn from deep within the earth.

Genotoxic: Damaging to DNA; pertaining to agents known to damage DNA.

Geological Log: A detailed description of all underground features (depth, thickness, type of formation) discovered during the drilling of a well.

Geophysical Log: A record of the structure and composition of the earth encountered when drilling a well or similar type of test hold or boring.

Geothermal/Ground Source Heat Pump: These heat pumps are underground coils to transfer heat from the ground to the inside of a building.

Germicide: Any compound that kills disease-causing microorganisms.

Giardia Lamblia: Protozoan in the feces of humans and animals that can cause severe gastrointestinal ailments. It is a common contaminant of surface waters.

Gigawatt (GW): One thousand megawatts (1,000 MW) or, one million kilowatts (1,000,000 kW) or one billion watts (1,000,000,000 watts) of electricity. One gigawatt is enough to supply the electric demand of about one million average California homes.

Gigawatt-Hour (GWH): One million kilowatt-hours of electric power.

Glass Containers: For recycling purposes, containers like bottles and jars for drinks, food, cosmetics and other products. When being recycled, container glass is generally separated into color categories for conversion into new containers, construction materials or fiberglass insulation.

Glazing: A covering of transparent or translucent material (typically glass or plastic) used for admitting light.

Global Climate Change: Gradual changing of global climates due to the buildup of carbon dioxide and other greenhouse gasses in the earth's atmosphere. Carbon dioxide produced by burning fossil fuels has reached levels greater than what can be absorbed by green plants and the seas.

Global Warming: An increase in the near surface temperature of the Earth. Global warming has occurred in the distant past as the result of natural influences, but the term is most often used to refer to the warming predicted to occur as a result of increased emissions of greenhouse gasses. Scientists generally agree that the Earth's surface has warmed by about 1 degree Fahrenheit in the past 140 years. The Intergovernmental Panel on Climate Change (IPCC) recently concluded that increased concentrations of greenhouse gasses are causing an increase in the Earth's surface temperature and that increased concentrations of sulfate aerosols have led to relative cooling in some regions, generally over and downwind of heavily industrialized areas.

Global Warming Potential (GWP): This is the impact of greenhouse gas emissions which contribute to the ‘greenhouse effect.’ Elevated concentrations of greenhouse gasses contribute to global warming and increased climate variability. Also referred to as Climate Change.

Glovebag: A polyethylene or polyvinyl chloride bag-like enclosure affixed around an asbestos-containing source (most often thermal system insulation) permitting the material to be removed while minimizing the release of airborne fibers to the surrounding atmosphere.

Gooseneck: A portion of a water service connection between the distribution system water main and a meter. It is sometimes called a pigtail.

Grab Crane, Hydraulic Crane: A hydraulic crane equipped with four mobile teeth forming a clamshell bucket. Grab cranes are used for demolition and/or handling waste and other materials.

Grab Sample: A single sample collected at a particular time and place that represents the composition of the water, air, or soil only at that time and place.

Grain Loading: The rate at which particles are emitted from a pollution source. Measurement is made by the number of grains per cubic foot of gas emitted.

Granular Activated Carbon Treatment: A filtering system often used in small water systems and individual homes to remove organics. Also used by municipal water treatment plants. GAC can be highly effective in lowering elevated levels of radon in water.

Grasscycling: Source reduction activities in which grass clippings are left on the lawn after mowing.

Grassed Waterway: Natural or constructed watercourse or outlet that is shaped or graded and established in suitable vegetation for the disposal of runoff water without erosion.

Gray Water: Domestic wastewater composed of wash water from kitchen, bathroom, and laundry sinks, tubs, and washers.

Green: An adjective used to describe something that is perceived to be beneficial to the environment.

Green Waste: Residual plant waste from gardening and green space maintenance. Garden waste, which is produced by individuals, is distinguished from municipal green waste, which is produced by community parks and engineering departments.

Greenfield Development: A tract of undeveloped property purchased with the intention of obtaining necessary permitting on which to operate a landfill. This would not include expansions to existing landfills.

Greenfield Plant: A new electric power generating facility built from the ground up on an undeveloped site.

Greenhouse Effect: The atmosphere lets most of the sun's rays filter through to warm the surface of the earth. The earth re-radiates this energy into space as high wavelength infrared radiation. Water vapor, carbon dioxide, and other gasses absorb this radiation emitted by the earth, preventing the energy from passing directly from the earth's surface into space, and so heating up the atmosphere. The increased greenhouse gas content in the atmosphere acts like double-glazing: If the input of the sun's rays remains constant within the greenhouse, the temperature will rise. Greenhouse gasses are gasses that absorb a portion of the sun's rays, such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), CFCs and HCFCs; synthetic gasses that attack the ozone layer; and CFC substitutes, such as HFC, PFC, and SF6. Veolia Environmental Services' emissions consist chiefly of CO2 and CH4. The latter has a greenhouse gas impact 21 times greater than CO2.

Greenhouse Effect: The warming of the Earth's atmosphere attributed to a buildup of carbon dioxide or other gases; some scientists think that this build-up allows the sun's rays to heat the Earth, while making the infra-red radiation atmosphere opaque to infra-red radiation, thereby preventing a counterbalancing loss of heat.

Greenhouse Effect: The presence of trace atmospheric gasses make the earth warmer than would direct sunlight alone. These gasses (carbon dioxide [CO2], methane [CH4], nitrous oxide [N2O], tropospheric ozone [O3], and water vapor [H2O]) allow visible light and ultraviolet light (short-wave radiation) to pass through the atmosphere and heat the earth's surface. This heat is re-radiated from the earth in form of infrared energy (long-wave radiation). The greenhouse gasses absorb part of that energy before it escapes into space. This process of trapping the long-wave radiation is known as the greenhouse effect. Scientists estimate that without the greenhouse effect, the earth's surface would be roughly 54 degrees Fahrenheit colder than it is today -- too cold to support life as we know it.

Greenhouse Gas (GHG): A gas, such as carbon dioxide or methane, which contributes to potential climate change.

Greenhouse Gases (GHG): Gases that contribute to the greenhouse effect. These include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), etc.

Grid: A system of interconnected power lines and generators that is managed so that the generators are dispatched as needed to meet the requirements of the customers connected to the grid at various points. Gridco is sometimes used to identify an independent company responsible for the operation of the grid.

Grid: The electric utility companies' transmission and distribution system that links power plants to customers through high power transmission line service (110 kilovolt [kv] to 765 kv); high voltage primary service for industrial applications and street rail and bus systems (23 kv-138 kv); medium voltage primary service for commercial and industrial applications (4 kv to 35); and secondary service for commercial and residential customers (120 v to 480 v). The grid can also refer to the layout of a gas distribution system of a city or town in which pipes are laid in both directions in the streets and connected at intersections.

Grinder Pump: A mechanical device that shreds solids and raises sewage to a higher elevation through pressure sewers.

Gross Alpha/Beta Particle Activity: The total radioactivity due to alpha or beta particle emissions as inferred from measurements on a dry sample.

Gross National Product (GNP): The total market value of the goods and services produced by a nation before deduction or depreciation charges and other allowance for capital consumption and is widely used as a measure of economic activity.

Gross Power-Generation Potential: The installed power generation capacity that landfill gas can support.

Ground Cover: Plants were grown to keep soil from eroding.

Ground Water: The supply of fresh water found beneath the Earth's surface, usually in aquifers, which supply wells and springs. Because ground water is a major source of drinking water, there is growing concern over contamination from leaching agricultural or industrial pollutants or leaking underground storage tanks.

Ground Water Under the Direct Influence (UDI) of Surface Water: Any water beneath the surface of the ground with: 1. significant occurrence of insects or other microorganisms, algae, or large-diameter pathogens; 2. significant and relatively rapid shifts in water characteristics such as turbidity, temperature, conductivity, or pH which closely correlate to climatological or surface water conditions. Direct influence is determined for individual sources in accordance with criteria established by a state.

Ground-Penetrating Radar: A geophysical method that uses high-frequency electromagnetic waves to obtain subsurface information.

Ground-Water Discharge: Ground water entering near coastal waters which has been contaminated by landfill leachate, deep well injection of hazardous wastes, septic tanks, etc.

Gully Erosion: Severe erosion in which trenches are cut to a depth greater than 30 centimeters (a foot). Generally, ditches deep enough to cross with farm equipment are considered gullies.

Habitat: The place where a population (e.g. human, animal, plant, microorganism) lives and its surroundings, both living and non-living.

Habitat Indicator: A physical attribute of the environment measured to characterize conditions necessary to support an organism, population, or community in the absence of pollutants; e.g. salinity of estuarine waters or substrate type in streams or lakes.

Half-Life: 1. The time required for a pollutant to lose one-half of its original concentration, example, the biochemical half-life of DDT in the environment is 15 years. 2. The time required for half of the atoms of a radioactive element to undergo self-transmutation or decay (half-life of radium is 1620 years). 3. The time required for the elimination of half a total dose from the body.

Halogen: A type of incandescent lamp with higher energy-efficiency than standard ones.

Bromine-containing compounds with long atmospheric lifetimes whose breakdown in the stratosphere causes depletion of ozone. Halons are used in firefighting.

Hammer Mill: A high-speed machine that uses hammers and cutters to crush, grind, chip, or shred solid waste.

Hard Water: Alkaline water containing dissolved salts that interfere with some industrial processes and prevent soap from sudsing.

Hauler: Garbage Collection Company that offers complete refuse removal service; many will also collect recyclables.

Hauling Fee:
A fee charged to roll-off customers calculated from the amount of time it takes to pick up their roll-off container or compactor, dispose of the waste and return it to the customer.

1. The potential for radiation, a chemical or other pollutant to cause human illness or injury. 2. In the pesticide program, the inherent toxicity of a compound. Hazard identification of a given substances is an informed judgment based on verifiable toxicity data from animal models or human studies.

Hazard Assessment:
Evaluating the effects of a stressor or determining a margin of safety for an organism by comparing the concentration which causes toxic effects with an estimate of exposure to the organism.

Hazard Evaluation:
A component of risk evaluation that involves gathering and evaluating data on the types of health injuries or diseases that may be produced by a chemical and on the conditions of exposure under which such health effects are produced.

Hazard Identification: Determining if a chemical or a microbe can cause adverse health effects in humans and what those effects might be.

Hazard Quotient:
The ratio of estimated site-specific exposure to a single chemical from a site over a specified period to the estimated daily exposure level, at which no adverse health effects are likely to occur.

Hazard Ratio: A term used to compare an animal's daily dietary intake of a pesticide to its LD 50 value. A ratio greater than 1.0 indicates that the animal is likely to consume a dose amount which would kill 50 percent of animals of the same species.

Hazardous Air Pollutants:
Air pollutants which are not covered by ambient air quality standards but which, as defined in the Clean Air Act, may present a threat of adverse human health effects or adverse environmental effects. Such pollutants include asbestos, beryllium, mercury, benzene, coke oven emissions, radio-nuclides, and vinyl chloride.

Hazardous Chemical:
An EPA designation for any hazardous material requiring an MSDS under OSHA's Hazard Communication Standard. Such substances are capable of producing fires and explosions or adverse health effects like cancer and dermatitis. Hazardous chemicals are distinct from hazardous waste.

Hazardous Substance:
1. Any material that poses a threat to human health and/or the environment. Typical hazardous substances are toxic, corrosive, ignitable, explosive, or chemically reactive. 2. Any substance designated by EPA to be reported if a designated quantity of the substance is spilled in the waters of the United States or is otherwise released into the environment.

Hazardous Waste:
By-products of society that can pose a substantial or potential hazard to human health or the environment when improperly managed. Possesses at least one of four characteristics (ignitability, corrosivity, reactivity, or toxicity).

Hazardous Waste: Waste that is designated such by regulatory agencies either because it has elevated levels of hazardous chemicals or materials, because it exhibits a potentially dangerous characteristic (e.g., ignitable, corrosive, etc.) or because the material belongs to a general family of materials which have been deemed hazardous by regulatory agencies. Waste, as defined by the Resource Conservation and Recovery Act that is reactive, toxic, corrosive, or otherwise dangerous to living things and/or the environment.

Hazardous Waste Landfill:
An excavated or engineered site where hazardous waste is deposited and covered.

Hazardous Waste Minimization:
Reducing the amount of toxicity or waste produced by a facility via source reduction or environmentally sound recycling.

Hazards Analysis: Procedures used to (1) identify potential sources of release of hazardous materials from fixed facilities or transportation accidents; (2) determine the vulnerability of a geographical area to a release of hazardous materials; and (3) compare hazards to determine which present greater or lesser risks to a community.

Hazards Identification:
Providing information on which facilities have extremely hazardous substances, what those chemicals are, how much there is at each facility, how the chemicals are stored, and whether they are used at high temperatures.

H-Coal Process:
A means of making coal cleaner so it will produce less ash and few sulfur emissions.

The vapor mixture trapped above a solid or liquid in a sealed vessel.

Heat Balance: The outdoor temperature at which a building's internal heat gain (from people, lights, and machines) is equal to the heat loss through windows, roof, and walls.

Heat Capacity:
The amount of heat necessary to raise the temperature of a given mass one degree. Heat capacity may be calculated by multiplying the mass by the specific heat.

Heat Engine: An engine that converts heat to mechanical energy.

Heat Gain: - an increase in the amount of heat contained in a space, resulting from direct solar radiation, heat flow through walls, windows, and other building surfaces, and the heat given off by people, lights, equipment, and other sources.

Heat Island Effect:
A "dome" of elevated temperatures over an urban area caused by structural and pavement heat fluxes, and pollutant emissions.

Heat Loss: A decrease in the amount of heat contained in a space, resulting from heat flow through walls, windows, roof and other building surfaces and from ex-filtration of warm air.

Heat Pump: An air-conditioning unit which is capable of heating by refrigeration, transferring heat from one (often cooler) medium to another (often warmer) medium, and which may or may not include a capability for cooling. This reverse-cycle air conditioner usually provides cooling in summer and heating in winter.

Heat Pump:
An electric device with both heating and cooling capabilities. It extracts heat from one medium at a lower (the heat source) temperature and transfers it to another at a higher temperature (the heat sink), thereby cooling the first and warming the second.

Heat Rate:
A number that tells how efficient a fuel-burning power plant is. The heat rate equals the Btu content of the fuel input divided by the kilowatt-hours of power output. Energy input per unit of time usually expressed in kWh\h or BTU\h

Heat Storm:
Heat storms occur when temperatures exceed 100 degrees Fahrenheit over a large area for three days in a row. Normal hot temperatures cause electricity demand to increase during the peak summertime hours of 4 to 7 p.m. when air conditioners are straining to overcome the heat. If a hot spell extends to three days or more, however, nighttime temperatures do not cool down, and the thermal mass in homes and buildings retains the heat from previous days. This heat build-up causes air conditioners to turn on earlier and to stay on later in the day. As a result, available electricity supplies are challenged during a higher, wider peak electricity consumption period.

Heat Transfer: Flow of heat energy induced by a temperature difference. Heat flow through a building envelope typically flows from a heated or hot area to a cooled or cold area.

Heating Degree Day:
A unit that measures the space heating needs during a given period of time.

Heating Load: The rate at which heat must be added to space in order to maintain the desired temperature within the space.

Heating Seasonal Performance Factor: A representation of the total heating output of a central air-conditioning heat pump in Btu’s during its normal usage period for heating, divided by the total electrical energy input in watt-hours during the same period.

Heating Value: The amount of heat produced by the complete combustion of a given amount of fuel.

Heavy Metals: Metallic elements with high atomic weights; (e.g. mercury, chromium, cadmium, arsenic, and lead); can damage living things at low concentrations and tend to accumulate in the food chain.

Heavy Water: A type of hydrogen atom that may be used as fuel for fusion power plants. Also called DEUTERIUM, it is found in abundance in the seas.

Hedging Contracts: Contracts which establish future prices and quantities of electricity independent of the short-term market. Derivatives may be used for this purpose. HELIOCHEMICAL - Using solar radiation to cause chemical reactions.

A process that uses the sun's rays to produce heat.

Heptachlor: An insecticide that was banned in some food products in 1975 and in all of them 1978. It was allowed for use in seed treatment until 1983. More recently it was found in milk and other dairy products in Arkansas and Missouri where dairy cattle were illegally fed treated seed.

Herbicide: A chemical pesticide designed to control or destroy plants, weeds, or grasses.

Herbivore: An animal that feeds on plants.

Hertz: A unit of electromagnetic wave frequency that is equal to one cycle per second. - It is named after Henrich R. Hertz.

Heterotrophic Organisms: Species that are dependent on organic matter for food.

High End Exposure (dose) Estimate:
An estimate of exposure or dose level received anyone in a defined population that is greater than the 90th percentile of all individuals in that population, but less than the exposure at the highest percentile in that population. A high-end risk descriptor is an estimate of the risk level for such individuals. Note that risk is based on a combination of exposure and susceptibility to the stressor.

High Intensity Discharge: A generic term for mercury vapor, metal halide, and high-pressure sodium lamps and fixtures.

High-Density Polyethylene:
A material used to make plastic bottles and other products that produce toxic fumes when burned.

High-Level Nuclear Waste Facility: Plant designed to handle disposal of used nuclear fuel, high-level radioactive waste, and plutonium waste.

High-Level Radioactive Waste (HLRW):
Waste generated in core fuel of a nuclear reactor, found at nuclear reactors or by nuclear fuel reprocessing; is a serious threat to anyone who comes near the waste without shielding.

High-Line Jumpers: Pipes or hoses connected to fire hydrants and laid on top of the ground to provide emergency water service for an isolated portion of a distribution system.

High-Risk Community:
A community located within the vicinity of numerous sites of facilities or other potential sources of environmental exposure/health hazards which may result in high levels of exposure to contaminants or pollutants.

High-Sulfur Coal: Coal whose weight is more than one percent sulfur.

High-to-Low-Dose Extrapolation:
The process of prediction of low exposure risk to humans and animals from the measured high-exposure-high-risk data involving laboratory animals.

Holding Pond:
A pond or reservoir, usually made of earth, built to store polluted runoff.

Holding Time: The maximum amount of time a sample may be stored before analysis.

Hollow Stem Auger Drilling:
Conventional drilling method that uses augurs to penetrate the soil. As the augers are rotated, soil cuttings are conveyed to the ground surface via augur spirals. DP tools can be used inside the hollow augers.

Homogeneous Area: In accordance with Asbestos Hazard and Emergency Response Act (AHERA) definitions, an area of surfacing materials, thermal surface insulation, or miscellaneous material that is uniform in color and texture.

Hood Capture Efficiency:
Ratio of the emissions captured by a hood and directed into a control or disposal device, expressed as a percent of all emissions.

Hopper: The hopper is the part of a garbage truck or compactor where trash is emptied before compaction into the container.

Horsepower (HP): A unit for measuring the rate of doing work. One horsepower equals about three-fourths of a kilowatt (745.7 watts).

Host: 1. In genetics, the organism, typically a bacterium, into which a gene from another organism is transplanted. 2. In medicine, an animal infected or parasitized by another organism.

Household Hazardous Waste:
Hazardous products used and disposed of by residential as opposed to industrial consumers. Includes paints, stains, varnishes, solvents, pesticides, and other materials or products containing volatile chemicals that can catch fire, react or explode, or that are corrosive or toxic.

Household Waste (Domestic Waste):
Solid waste, composed of garbage and rubbish, which normally originates in a private home or apartment house. Domestic waste may contain a significant amount of toxic or hazardous waste.

Hot (Colloquial):
The word is sometimes used to describe electric utility lines that are carrying electric currently. It also is used to refer to anything that is highly radioactive.

Hot Dry Rock: A geothermal resource created when impermeable, subsurface rock structures, typically granite rock 15,000 feet or more below the earth's surface, are heated by geothermal energy. The resource is being investigated as a source of energy production.

HSPF (Heating Seasonal Performance Factor): A measure of heating efficiency for the total heating output of a central air-conditioning heat pump. Efficiency is derived according to federal test methods by using the total Btu’s during its normal usage period for heating divided by the total electrical energy input in watt-hours during the same period.

Human Equivalent Dose:
A dose which, when administered to humans, produces an effect equal to that produced by a dose in animals.

Human Exposure Evaluation:
Describing the nature and size of the population exposed to a substance and the magnitude and duration of their exposure.

Human Health Risk: The likelihood that a given exposure or series of exposures may have damaged or will damage the health of individuals.

Humus: The end product of composting, also called compost.

HVAC (Heating Ventilation and Air Conditioning):
A system that provides heating, ventilation and/or cooling within or associated with a building.

Hybrid Vehicle: Usually a hybrid EV, a vehicle that employs a combustion engine system together with an electric propulsion system. Hybrid technologies expand the usable range of EVs beyond what an all-electric-vehicle can achieve with batteries only.

Hydraulic Conductivity:
The rate at which water can move through a permeable medium. (i.e. the coefficient of permeability.)

Hydraulic Gradient:
In general, the direction of groundwater flows due to changes in the depth of the water table.

Hydrocarbons (HC): Chemical compounds that consist entirely of carbon and hydrogen. Oil and natural gas are hydrocarbons.

Hydroelectric Power: Electricity produced by falling water that turns a turbine generator. It is also referred to as HYDRO.

Hydroelectric Spill Generation: Hydroelectric generation in existence prior to January 1, 1998, that has no storage capacity and that, if backed down, would spill. This term also refers to a hydro resource that has exceeded or has inadequate storage capacity and is spilling, even though generators are operating at full capacity.

Hydrochloroflurocarbon (HCFC):
A compound that consists of hydrogen, chlorine, fluorine and carbon.

Hydrofluorocarbon (HFC): A compound that consists of hydrogen, fluorine, and carbon.

Hydrogen Sulfide (H2S):
Gas emitted during organic decomposition. It is also a by-product of oil refining and burning. Smells like rotten eggs and, in heavy concentration, can kill or cause illness.

Hydrogeological Cycle: The natural process recycling water from the atmosphere down to (and through) the earth and back to the atmosphere again.

The geology of ground water, with particular emphasis on the chemistry and movement of water.

Hydrologic Cycle:
Movement or exchange of water between the atmosphere and earth.

The science dealing with the properties, distribution, and circulation of water.

Hydrolysis: The decomposition of organic compounds by interaction with water.

Hydronic: A ventilation system using heated or cooled water pumped through a building.

Hydronic Heating: A system that heats a space using hot water which may be circulated through a convection or fan coil system or through a radiant baseboard or floor system.

Having a strong affinity for water.

Hydrophobic: Having a strong aversion to water.

A water system, usually small, in which a water pump is automatically controlled by the pressure in a compressed air tank.

Hydrothermal Systems:
Underground reservoirs that produce either dry steam or a mixture of steam and water.

: A process that uses water to help produce pipeline-quality gas from coal.

Hypersensitivity Diseases:
Diseases characterized by allergic responses to pollutants; diseases most clearly associated with indoor air quality are asthma, rhinitis, and pneumonic hypersensitivity.

Bottom waters of a thermally stratified lake. The hypolimnion of a eutrophic lake is usually low or lacking in oxygen.

Hypoxia/Hypoxic Waters:
Waters with dissolved oxygen concentrations of less than 2 ppm, the level generally accepted as the minimum required for most marine life to survive and reproduce.

Ignitable: Capable of burning or causing a fire.

Imbalance Energy:
The real-time change in generation output or demand requested by the ISO to maintain the reliability of the ISO-controlled grid. Sources of imbalance energy include regulation, spinning and non-spinning reserves, replacement reserve, and energy from other generating units that are able to respond to the ISO's request for more or less energy.

Imhoff Cone: A clear, cone-shaped container used to measure the volume of settleable solids in a specific volume of water.

Immiscibility: The inability of two or more substances or liquids to readily dissolve into one another, such as soil and water. Immiscibility The inability of two or more substances or liquids to readily dissolve into one another, such as soil and water.

Impermeable: Not easily penetrated. The property of a material or soil that does not allow, or allows only with great difficulty, the movement or passage of water.

Imports: Municipal solid waste and recyclables that have been transported to a state or locality for processing or final disposition (but that did not originate in that state or locality).

Imports (Electric Utility): Power capacity or energy obtained by one utility from others under purchase or exchange agreement.

Impoundment: A body of water or sludge confined by a dam, dike, floodgate, or another barrier.

In-Line Filtration: Pre-treatment method in which chemicals are mixed with the flowing water; commonly used in pressure filtration installations. Eliminates the need for flocculation and sedimentation.

In Situ:
In its original place; unmoved unexcavated; remaining at the site or in the subsurface.

In-Situ Combustion: An experimental means of recovering hard-to-get petroleum by burning some of the oil in its natural underground reservoir. It is also called FIREFLOODING.

In-Situ Flushing:
Introduction of large volumes of water, at times, supplemented with cleaning compounds, into soil, waste, or ground water to flush hazardous contaminants from a site.

In-Situ Gasification: Converting coal into synthetic gas at the place where the coal is found in nature.

In-Situ Oxidation:
Technology that oxidizes contaminants dissolved in ground water, converting them into insoluble compounds.

In-Situ Stripping:
Treatment system that removes or "strips" volatile organic compounds from contaminated ground or surface water by forcing an airstream through the water and causing the compounds to evaporate.

In-Situ Vitrification:
Technology that treats contaminated soil in place at extremely high temperatures, at or more than 3000 degrees Fahrenheit.

In Vitro: Testing or action outside an organism (e.g. inside a test tube or culture dish.)

In Vivo: Testing or action inside an organism.

Incandescent Lamp: An electric lamp in which a filament is heated by an electric current until it emits visible light.

Incineration: A treatment technology involving the destruction of waste by controlled burning at high temperatures; e.g., burning sludge to remove the water and reduce the remaining residues to a safe, non-burnable ash that can be disposed of safely on land, in some waters, or in underground locations.

A thermal waste treatment method involving combustion (the technology and temperature vary depending on the type of waste), and flue gas treatment. This technique yields three types of residue: bottom ash, fly ash and flue gas treatment residue. The heat generated by incineration is recovered at most facilities to produce energy (electricity or heat).

Incineration at Sea: Disposal of waste by burning at sea on specially-designed incinerator ships.

Incinerator: A furnace for burning waste under controlled conditions.

Incompatible Waste: A waste unsuitable for mixing with another waste or material because it may react to form a hazard.

Independent Power Producer (IPP):
An Independent Power Producer (IPP) generates power that is purchased by an electric utility at wholesale prices. The utility then resells this power to end-use customers. Although IPPs generate power, they are not franchised utilities, government agencies or QFs. IPPs usually do not own transmission lines to transmit the power that they generate.

Independent System Operator (ISO):
A neutral operator responsible for maintaining the instantaneous balance of the grid system. The ISO performs its function by controlling the dispatch of flexible plants to ensure that loads match resources available to the system.

In biology, any biological entity or processes, or community whose characteristics show the presence of specific environmental conditions. 2. In chemistry, a substance that shows a visible change, usually of color, at the desired point in a chemical reaction. 3. A device that indicates the result of a measurement; e.g. a pressure gauge or a moveable scale.

Indigenous Energy Resources:
Power and heat derived from sources native to California. These include geothermal, hydro, biomass, solar and wind energy. The term usually is understood to include cogeneration facilities.

Indirect Discharge:
Introduction of pollutants from a non-domestic source into a publicly owned waste-treatment system. Indirect dischargers can be commercial or industrial facilities whose wastes enter local sewers.

Indoor Air Pollution: Chemical, physical or biological contaminants in indoor air.

Indoor Air Quality (IAQ):
Acceptable IAQ is air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which a substantial majority (80 percent or more) of the people exposed do not express dissatisfaction.

Industrial Ecology:
An approach to the design of industrial products and processes that evaluate such activities through the dual perspectives of product competitiveness and environmental interactions.

Industrial Process Waste:
Residues produced during manufacturing operations.

Industrial Sludge:
Semi-liquid residue or slurry remaining from the treatment of industrial water and wastewater.

Industrial Source Reduction:
Practices that reduce the amount of any hazardous substance, pollutant, or contaminant entering any waste stream or otherwise released into the environment. Also, reduces the threat to public health and the environment associated with such releases. The term includes equipment or technology modifications, substitution of raw materials, and improvements in housekeeping, maintenance, training or inventory control.

Industrial Waste: Unwanted materials from an industrial operation; may be liquid, sludge, solid, or hazardous waste.

Inert Waste:
Waste that undergoes no significant physical, chemical or biological transformation. Inert waste does not dissolve burn or otherwise physically or chemically react. It is not biodegradable and does not adversely affect other matter with which it comes into contact in a way likely to give rise to environmental pollution or harm to health.

Inert Ingredient:
Pesticide components such as solvents, carriers, dispersants, and surfactants that are not active against target pests. Not all inert ingredients are innocuous.

Inertial Separator:
A device that uses centrifugal force to separate waste particles.

Infectious Agent:
Any organism, such as a pathogenic virus, parasite, or bacterium, that is capable of invading body tissues, multiplying, and causing disease.

Infectious Waste:
Hazardous waste capable of causing infections in humans, including contaminated animal waste; human blood and blood products; isolation waste, pathological waste; and discarded sharps (needles, scalpels or broken medical instruments).

1. The penetration of water through the ground surface into a sub-surface soil or the penetration of water from the soil into sewer or other pipes through defective joints, connections, or manhole walls. 2. The technique of applying large volumes of waste water to land to penetrate the surface and percolate through the underlying soil.

The uncontrolled inward leakage of air through cracks and gaps in the building envelope, especially around windows, doors and duct systems.

Infiltration Barrier:
A material placed on the outside or the inside of exterior wall framing to restrict inward air leakage, while permitting the outward escape of water vapor from the wall cavity.

Infiltration Gallery: A sub-surface groundwater collection system, typically shallow in depth, constructed with open-jointed or perforated pipes that discharge collected water into a watertight chamber from which the water is pumped to treatment facilities and into the distribution system. Usually located close to streams or ponds.

Infiltration Rate: The quantity of water that can enter the soil in a specified time interval.

Inflow: Entry of extraneous rain water into a sewer system from sources other than infiltration, such as basement drains, manholes, storm drains, and street washing.

Influent: Water, wastewater, or other liquid flowing into a reservoir, basin, or treatment plant.

Generally refers to the recharging and refueling network necessary to successful development, production, commercialization, and operation of alternative fuel vehicles, including fuel supply, public and private recharging and refueling facilities, standard specifications for refueling outlets, customer service, education and training, and building code regulations.

Inhalable Particles: All dust capable of entering the human respiratory tract.

Injection (Petroleum):
Forcing gas or water into an oil well to increase pressure and cause more oil to come to the surface.

Injection Well: A well into which fluids are injected for purposes such as waste disposal, improving the recovery of crude oil, or solution mining.

Injection Zone:
A geological formation receiving fluids through a well.

Innovative Technologies: New or inventive methods to treat effectively hazardous waste and reduce risks to human health and the environment.

Innovative Treatment Technologies:
Technologies whose routine use is inhibited by lack of data on performance and cost.

1. Bacteria or fungi injected into compost to start the biological action. 2. A medium containing organisms, usually bacteria or a virus, that is introduced into cultures or living organisms.

Inorganic Chemicals:
Chemical substances of mineral origin, not of basically carbon structure.

Inorganic Waste:
Waste composed of the material other than plant or animal matter, such as sand, dust, glass, and many synthetics.

Insecticide: A pesticide compound specifically used to kill or prevent the growth of insects.

Insolation: The total amount of solar radiation (direct, diffuse, and reflected) striking a surface exposed to the sky.

Institutional Waste:
Waste generated at institutions such as schools, libraries, hospitals, prisons, etc.

Instream Use: Water use taking place within a stream channel; e.g., hydro-electric power generation, navigation, water quality improvement, fish propagation, recreation.

Insulation, Thermal:
A material having a relatively high resistance to heat flow and used principally to retard heat flow.

Integrated Exposure Assessment: Cumulative summation (over time) of the magnitude of exposure to a toxic chemical in all media.

Integrated Pest Management (IPM):
A mixture of chemical and other, non-pesticide, methods to control pests.

Integrated Pollution Prevention and Control (IPPC):
IPPC Directive is about minimizing pollution from various point sources throughout the European Union. Based on the concept of Best Available Techniques (or BAT),

Integrated Resource Planning (IRP):
A public planning process and framework within which the costs and benefits of both demand- and supply-side resources are evaluated to develop the least-total-cost mix of utility resource options. In many states, IRP includes a means for considering environmental damages caused by electricity supply/transmission and identifying cost-effective energy efficiency and renewable energy alternatives. IRP has become a formal process prescribed by law in some states and under some provisions of the Clean Air Act amendments of 1992.

Integrated Resource Planning Principles:
The underlying principles of IRP can be distinguished from the formal process of developing an approved utility resource plan for utility investments in supply- and demand-side resources. A primary principle is to provide a framework for comparing a variety of supply- and demand-side and transmission resource costs and attributes outside of the basic provision (or reduction) of electric capacity and energy. These resources may be owned or constructed by any entity and may be acquired through contracts as well as through direct investments. Another principle is the incorporation of risk and uncertainty into the planning analysis. The public participation aspects of IRP allow public and regulatory involvement in the planning rather than the siting stage of project development.

Integrated Services Digital Network (ISDN):
A 128 Kbps (kilobytes per second) digital telephone service available in many parts of the country though not universally available that may be able to substitute for fiber optic cable in every respect except possibly television transmission.

Integrated Solid Waste Management:
Coordinated use of a set of waste management methods, each of which can play a role in an overall MSVVM plan.

Integrated Waste Management:
Using a variety of practices to handle municipal solid waste; can include source reduction, recycling, incineration, and landfilling.

Interceptor Sewers:
Large sewer lines that, in a combined system, control the flow of sewage to the treatment plant. In a storm, they allow some of the sewage to flow directly into a receiving stream, thus keeping it from overflowing onto the streets. Also used in separate systems to collect the flows from main and trunk sewers and carry them to treatment points.

Interchange (Electric Utility):
The agreement among interconnected utilities under which they buy, sell and exchange power among themselves. This can, for example, provide for economy energy and emergency power supplies.

Interconnection (Electric Utility): The linkage of transmission lines between two utilities, enabling power to be moved in either direction. Interconnections allow the utilities to help contain costs while enhancing system reliability.

Interested Party: Any person whom the commission finds and acknowledges as having a real and direct interest in any proceeding or action carried on, under, or as a result of the operation of, this division.

Interface: The common boundary between two substances such as a water and a solid, water and a gas, or two liquids such as water and oil.

Interfacial Tension: The strength of the film separating two immiscible fluids (e.g. oil and water) measured in dynes per, or millidynes per centimeter.

Internal Combustion Engine: An engine in which fuel is burned inside the engine. A car's gasoline engine or rotary engine is an example of an internal combustion engine. It differs from engines having an external furnace, such as a steam engine.

Internal Dose:
In exposure assessment, the amount of a substance penetrating the absorption barriers (e.g. skin, lung tissue, gastrointestinal tract) of an organism through either physical or biological process.

International Standards Organization (ISO):
A non-governmental organization chartered to develop voluntary technical standards that aim to make the development, manufacture, and supply of goods and services safer, cleaner and more efficient.

Interruptible Service (Electric Utility):
Electricity supplied under agreements that allow the supplier to curtail or stop service at times.

Interstate Carrier Water Supply:
A source of water for drinking and sanitary use on planes, buses, trains, and ships operating in more than one state. These sources are federally regulated.

Interstitial Monitoring: The continuous surveillance of the space between the walls of an underground storage tank.

Inversion: A layer of warm air that prevents the rise of cooling air and traps pollutants beneath it; can cause an air pollution episode.

Intertie: A transmission line that links two or more regional electric power systems.

Ion: An electrically charged atom or group of atoms.

Ion Exchange Treatment: A common water-softening method often found on a large scale at water purification plants that remove some organics and radium by adding calcium oxide or calcium hydroxide to increase the pH to a level where the metals will precipitate out.

Ionization Chamber: A device that measures the intensity of ionizing radiation.

Ionizing Radiation: Radiation that can strip electrons from atoms; e.g. alpha, beta, and gamma radiation.

Irradiated Food: Food subject to brief radioactivity, usually gamma rays, to kill insects, bacteria, and mold, and to permit storage without refrigeration.

Irradiation: Exposure to radiation of wavelengths shorter than those of visible light (gamma, x-ray, or ultra- violet), for medical purposes, to sterilize milk or other foodstuffs, or to induce polymerization of monomers or vulcanization of rubber.

Irreversible Effect: Effect characterized by the inability of the body to partially or fully repair injury caused by a toxic agent.

Irrigation: Applying water or wastewater to land areas to supply the water and nutrient needs of plants.

Irrigation Efficiency:
The amount of water stored in the crop root zone compared to the amount of irrigation water applied.

Irrigation Return Flow: Surface and subsurface water which leaves the field following application of irrigation water.

Irritant: A substance that can cause irritation of the skin, eyes, or respiratory system. Effects may be acute from a single high-level exposure, or chronic from repeated low-level exposures to such compounds as chlorine, nitrogen dioxide, and nitric acid.

ISO: International Standards Organization.

ISO 9001 Quality Management Systems: The ISO 9001 standard assesses the capacity of an organization to meet the client's requirements with regards to the quality of a product or service.

ISO 14001 Environmental Management Systems:
The ISO 14001 standard evaluates the ability of an organization to control the impact on the environment of its activities and to comply with regulations.

ISO 14031: This standard evaluates an organization's compliant use of management indicators, comparing the past and present environmental performance of the company's business on the basis of the "plan, do, check, act" process.

More than one sample point exhibiting the same isolate concentration.

Isopleth: The line or area represented by an is concentration.

A variation of an element that has the same atomic number of protons but a different weight because of the number of neutrons. Various isotopes of the same element may have different radioactive behaviors, some are highly unstable.

The condition in which the hydraulic or other properties of an aquifer are the same in all directions.

Itinerant Waste Buyer: A person who moves around the streets buying (or bartering for) reusable and recyclable materials.

Jar Test: A laboratory procedure that simulates a water treatment plant's coagulation/flocculation units with differing chemical doses, mix speeds, and settling times to estimate the minimum or ideal coagulant dose required to achieve certain water quality goals.

Joule: A unit of work or energy equal to the amount of work done when the point of application of a force of 1 newton is displaced 1 meter in the direction of the force. It takes 1,055 joules to equal a British thermal unit. It takes about 1 million joules to make a pot of coffee.

Karst: A geologic formation of irregular limestone deposits with sinks, underground streams, and caverns.

kBtu: One-thousand (1,000) Btus.

Certain colorless, low-sulfur oil products that burn without producing much smoke.

Kilovolt (kV): One-thousand volts (1,000). Distribution lines in residential areas usually are 12 kV (12,000 Volts).

Kilowatt (kW): One thousand (1,000) watts. A unit of measure of the amount of electricity needed to operate given equipment. On a hot summer afternoon a typical home, with central air conditioning and other equipment in use, might have a demand of four kW each hour.

Kilowatt- Hour (kWh):
The most commonly-used unit of measure telling the amount of electricity consumed over time. It means one kilowatt of electricity supplied for one hour. In 1989, a typical California household consumes 534 kWh in an average month.

Kinetic Energy:
Energy possessed by a moving object or water body.

Kinetic Rate Coefficient:
A number that describes the rate at which a water constituent such as a biochemical oxygen demand or dissolved oxygen rises or falls, or at which an air pollutant reacts.

Kyoto Accord:
Agreed in Japan 1997 targets 'carbon-rich' gasses and commits 38 industrialized countries to emissions cut of 5.2% by 2010.

Landfill Gas: Gas generated by the natural degrading and decomposition of municipal solid waste by anaerobic microorganisms in sanitary landfills. The gasses produced, carbon dioxide, and methane can be collected by a series of low-level pressure wells and can be processed into a medium Btu gas that can be burned to generate steam or electricity.

Lagoon: 1. A shallow pond where sunlight, bacterial action, and oxygen work to purify wastewater; also used for storage of wastewater or spent nuclear fuel rods. 2. A shallow body of water, often separated from the sea by coral reefs or sandbars.

Land Application:
Discharge of wastewater onto the ground for treatment or reuse.

Land Application:
The even distribution of the land of effluent from animal husbandry, soil improvers, fertilizers, crop-care products and wastewater treatment sludge, etc.

Land Ban:
Phasing out of the land disposal of most untreated hazardous wastes, as mandated by the 1984 RCRA amendments.

Land Disposal Restrictions: Rules that require hazardous wastes to be treated before disposal on land to destroy or immobilize hazardous constituents that might migrate into soil and ground water.

Land Farming (of Waste):
A disposal process in which hazardous waste deposited on or in the soil is degraded naturally by microbes.

Landfill: An installation designed to treat and store waste under optimal safety conditions. The European Union recognizes three classes of the landfill: stabilized hazardous waste landfills, called class 1; landfills that take in the household and similar waste, called class 2; and inert waste, or class 3, landfill sites. In the United States, there are two classes of the landfill: Class 1 for non-hazardous solid wastes and Class 2 for hazardous wastes.

A modern engineered way to deposit waste into the ground and still protect the environment. As the landfill is built, the base of the cell is lined with a protective layer and materials are installed to monitor and collect leachate and gas emissions. As waste is deposited over the liner, it is compacted with heavy machinery in an effort to get the maximum amount of waste in an area. At the end of the day, the waste is covered with soil or special fabric cover (unless specifically exempted by state regulators.) Once the lined area is completely full, it is covered with an engineer-designed cap. Regulations mandate the periodic testing of ground water, leachate levels, and gas emissions. Landfills are accounted for a separate line of business within the WMI organization. Different types of landfills include MSW, C&D, Asbestos Monofil, Ash Monofil, Special Waste and Hazardous Waste.

Landfills: 1. Sanitary landfills are disposal sites for non-hazardous solid wastes spread in layers, compacted to the smallest practical volume, and covered by material applied at the end of each operating day. 2. Secure chemical landfills are disposal sites for hazardous waste, selected and designed to minimize the chance of release of hazardous substances into the environment.

Landfill, Construction & Demolition (C&D):
A landfill that has been permitted by a state regulatory agency to accept Construction and Demolition waste. This type of landfill must have properties and design features specific to this type of landfilling that have been established by the state regulatory agency.

Landfill Footprint:
Parcels of land that are designated and permitted to perform landfilling activities. This would include the entrance, staging area, buffer area and the area that will accept waste for disposal (the waste footprint area).

Landfill Gas:
Municipal solid waste contains significant portions of organic materials that produce a variety of gaseous products when dumped, compacted, and covered in landfills. Anaerobic bacteria thrives in the oxygen-free environment, resulting in the decomposition of the organic materials and the production of primarily carbon dioxide, and methane. Landfill gas consists of 50-60% methane and 35-40% carbon dioxide.

Landfill Gas Generators: Utilizing landfill gas to fuel a generator.

Landfill Gases: Gases arising from the decomposition of organic wastes; principally methane, carbon dioxide, and hydrogen sulfide. Such gasses may cause explosions at landfills.

Landfill, Hazardous Waste:
Wastes that exhibit certain characteristics may be regulated by RCRA. A waste may be considered hazardous if it is ignitable (i.e., burns readily), corrosive, or reactive (e.g., explosive). Waste may also be considered hazardous if it contains certain amounts of toxic chemicals. In addition to these characteristic wastes, EPA has also developed a list of over 500 specific hazardous wastes. Hazardous waste takes many physical forms and may be solid, semi-solid, or even liquid. A hazardous waste landfill is built to specific regulations to allow for the disposal of waste designated by regulatory agencies as being hazardous. These regulations are far more stringent that for an MSW landfill. WMI has 5 secure hazardous waste landfills permitted under RCRA. These sites all operate under the name "Chemical Waste Management" (CWM).

Landfill, Municipal Solid Waste (MSW):
A landfill that has been permitted by a state regulatory agency to accept municipal solid waste. This type of landfilling must have properties and design features specific to this type of landfill that have been established by the state regulatory agency.

Landfill Sites: A landfill is a carefully designed structure built into or on top of the ground in which rubbish is isolated from the surrounding environment (groundwater, air, soil). Landfills are not designed to break down waste, merely to bury it. The modern landfill offers much more protection for the environment and for local people than traditional dumps did. Problems with odors, litter, vermin, etc., are greatly reduced by the careful management of the site.

Landfilling: The final disposal of solid waste by placing it in a controlled fashion in a place intended to be permanent. The Source Book uses this term for both controlled dumps and sanitary landfills.

Landscape: The traits, patterns, and structure of a specific geographic area, including its biological composition, its physical environment, and its anthropogenic or social patterns. An area where interacting ecosystems are grouped and repeated in similar form.

Landscape Characterization: Documentation of the traits and patterns of the essential elements of the landscape.

Landscape Ecology:
The study of the distribution patterns of communities and ecosystems, the ecological processes that affect those patterns, and changes in pattern and process over time.

Landscape Indicator:
A measurement of the landscape, calculated from mapped or remotely sensed data, used to describe spatial patterns of land use and land cover across a geographic area. Landscape indicators may be useful as measures of certain kinds of environmental degradation such as forest fragmentation.

Langelier Index (LI): An index reflecting the equilibrium pH of water with respect to calcium and alkalinity; used in stabilizing water to control both corrosion and scale deposition.

Laser: A very intense, uniform beam of electromagnetic radiation. It is an Acronym for Light Amplification by Simulated Emission of Radiation.

Laser Induced Fluorescence: A method for measuring the relative amount of soil and/or groundwater with an in-situ sensor.

Latency: Time from the first exposure of a chemical until the appearance of a toxic effect.

Latent Heat: A change in the heat content that occurs without a corresponding change in temperature, usually accompanied by a change of state (as from liquid to vapor during evaporation).

Latent Load: The cooling load caused by moisture in the air.

Lateral Sewers:
Pipes that run under city streets and receive the sewage from homes and businesses, as opposed to domestic feeders and main trunk lines.

The angular distance north or south of the equator, measured in degrees of arc.

Laundering Weir:
Sedimentation basin overflow weir.

Layoff (Electric Utility):
 The excess capacity of a generating unit, available for a limited time under the terms of a power sales agreement.

Lay Up: Lay up is another term for cold storage and describes the status of equipment (such as a power plant) that has been placed in storage ("mothballed") for later use.

LC 50/Lethal Concentration:
Median level concentration, a standard measure of toxicity. It tells how much of a substance is needed to kill half of a group of experimental organisms in a given time.

LD 50/ Lethal Dose: The dose of a toxicant or microbe that will kill 50 percent of the test organisms within a designated period. The lower the LD 50, the more toxic the compound.

Ldlo: Lethal dose low; the lowest dose in an animal study at which lethality occurs.

Water that collects contaminants as it trickles through wastes, pesticides or fertilizers. Leaching may occur in farming areas, feedlots, and landfills, and may result in hazardous substances entering surface water, ground water, or soil.

Leachate: Liquid (which may be partly produced by the decomposition of organic matter) that has seeped through a landfill or a compost pile and has accumulated bacteria and other possibly harmful dissolved or suspended materials. If uncontrolled, leachate can contaminate both groundwater and surface water.

Leachate Collection System:
A system that gathers leachate and pumps it to the surface for treatment.

Leachate Pond: A pond or tank constructed at a landfill to receive the leachate from the area. Usually, the pond is designed to provide some treatment of the leachate, by allowing settlement of solids or by aeration to promote biological processes.

Leaching: The process by which soluble constituents are dissolved and filtered through the soil by a percolating fluid.

Lead (Pb): A heavy metal that is hazardous to health if breathed or swallowed. Its use in gasoline, paints, and plumbing compounds has been sharply restricted or eliminated by federal laws and regulations.

Lead Service Line:
A service line made of lead which connects the water to the building inlet and any lead fitting connected to it.

Leaded Gasoline: Gasoline containing tetraethyl lead, an important constituent in antiknock gasoline. Leaded gasoline is no longer sold in the United States.

Lean Burn: Lean-burn is the ability to ignite air and fuel mixtures that contain higher amounts of air than normally used.

Legionella: A genus of bacteria, some species of which have caused a type of pneumonia called Legionnaires Disease.

Lethal Concentration 50: Also referred to as LC50, a concentration of a pollutant or effluent at which 50 percent of the test organisms die; a common measure of acute toxicity.

Lethal Dose 50:
Also referred to as LD50, the dose of a toxicant that will kill 50 percent of test organisms within a designated period of time; the lower the LD 50, the more toxic the compound.

Life Cycle Assessment (LCA): A compilation and evaluation of the inputs, outputs and the potential environmental impacts of a product or system throughout its life cycle.

Life Cycle Cost:
Amount of money necessary to own, operate and maintain a building over its useful life.

Life Cycle Inventory (LCI):
The part of the LCA process that quantities the energy, input of raw material and releases into the environment that are associated with each stage of production.

Life Cycle of a Product: All stages of a product's development, from an extraction of fuel for power to production, marketing, use, and disposal.

Life Extension:
A term used to describe capital expenses which reduce operating and maintenance costs associated with continued operation of electric utility boilers. Such boilers usually have a 40-year operating life under normal circumstances.

Lifetime Average Daily Dose:
Figure for estimating excess lifetime cancer risk.

Lifetime Exposure: Total amount of exposure to a substance that a human would receive in a lifetime (usually assumed to be 70 years).

Lift: In a sanitary landfill, a compacted layer of solid waste and the top layer of cover material.

Light Emitting Diode: A long-lasting illumination technology used for exit signs which require very little power

Light Non-Aqueous Phase Liquid (LNAPL):
A non-aqueous phase liquid with a specific gravity less than 1.0. Because the specific gravity of water is 1.0, most LNAPLs float on top of the water table. Most common petroleum hydrocarbon fuels and lubricating oils are LNAPLs.

Light Water Reactor (LWR):
A nuclear power unit that uses ordinary water to cool its core. The LWR may be a boiling water reactor or a pressurized water reactor.

Lignite: Brownish black coal having qualities in between those of bituminous coal and peat. The texture of the original wood often is visible in lignite.

Limestone Scrubbing:
Use of a limestone and water solution to remove gaseous stack-pipe sulfur before it reaches the atmosphere.

Limit of Detection (LOD): The minimum concentration of a substance being analyzed test that has a 99 percent probability of being identified.

Limited Degradation: An environmental policy permitting some degradation of natural systems but terminating at a level well beneath an established health standard.

Limiting Factor: A condition whose absence or excessive concentration, is incompatible with the needs or tolerance of a species or population and which may have a negative influence on their ability to thrive.

Limnology: The study of the physical, chemical, hydrological, and biological aspects of fresh water bodies.

Lindane: A pesticide that causes adverse health effects in domestic water supplies and is toxic to freshwater fish and aquatic life.

Liner: 1. A relatively impermeable barrier designed to keep leachate inside a landfill. Liner materials include plastic and dense clay. 2. An insert or sleeve for sewer pipes to prevent leakage or infiltration.

Lipid Solubility: The maximum concentration of a chemical that will dissolve in fatty substances. Lipid soluble substances are insoluble in water. They will very selectively disperse through the environment via uptake in living tissue.

Lipofit: Fatty concentrate produced by the treatment of fatty waste using the Lipoval process. The properties of Lipofit are close to those of heavy fuel, except that is has a much lower sulfur content. Under regulations, it is considered a fuel in its own right and can be used in facilities classified 2910B (combustion plants).

Lipoval: This separating process is designed for the treatment of liquid fatty waste mainly from restaurant gully traps (80%), but also from the food industry and wastewater treatment plant oil extractors. The Lipoval process dynamically separates fatty waste into three phases: a fatty concentrate that can be used as a replacement fuel (Lipofit), solid sediment, and a treated aqueous phase discharged into the sewer.

Liquefaction: Changing a solid into a liquid. The process of making synthetic liquid fuel from coal. The term also is used to mean a method for making large amounts of gasoline and heating oil from petroleum.

Liquefied Gases: Gases that have been or can be changed into liquid form. These include butane, butylene, ethane, ethylene, propane and propylene.

Liquefied Natural Gas (LNG):
Natural gas that has been condensed to a liquid, typically by cryogenically cooling the gas to minus 260 degrees Fahrenheit (below zero).

Liquefied Petroleum Gas (LPG): A mixture of gaseous hydrocarbons, mainly propane and butane that change into liquid form under moderate pressure. LPG or propane is commonly used as a fuel for rural homes for space and water heating, as a fuel for barbecues and recreational vehicles, and as a transportation fuel. It is normally created as a by-product of petroleum refining and from natural gas production.

Liquid Brine:
A type of geothermal energy resource that depends on naturally occurring hot water solution found within the earth.

Liquid Injection Incinerator:
Commonly used system that relies on high pressure to prepare liquid wastes for incineration by breaking them up into tiny droplets to allow easier combustion.

List: Shorthand term for EPA list of violating facilities or firms debarred from obtaining government contracts because they violated certain sections of the Clean Air or Clean Water Acts. The list is maintained by The Office of Enforcement and Compliance Monitoring.

Listed Waste: Wastes listed as hazardous under RCRA but which have not been subjected to the Toxic Characteristics Listing Process because the dangers they present are considered self-evident.

Mineralogy, grain size, texture, and other physical properties of granular soil, sediment, or rock.

Litter: 1. The highly visible portion of solid waste carelessly discarded outside the regular garbage and trash collection and disposal system. 2. Leaves and twigs fallen from forest trees.

Littoral Zone: 1. That portion of a body of fresh water extending from the shoreline lake ward to the limit of occupancy of rooted plants. 2. A strip of land along the shoreline between the high and low water levels.

Load: The amount of electric power supplied to meet one or more end user's needs. It is an end-use device or an end-use customer that consumes power. The load should not be confused with demand, which is the measure of power that a load receives or requires.

Load Centers:
A geographical area where large amounts of power are drawn by end-users.

Load Diversity: The condition that exists when the peak demands of a variety of electric customers occur at different times. This is the objective of "load molding" strategies, ultimately curbing the total capacity requirements of a utility.

Load Factor: A percent telling the difference between the amount of electricity a consumer used during a given time span and the amount that would have been used if the usage had stayed at the consumer's highest demand level during the whole time. The term also is used to mean the percentage of capacity of an energy facility - such as power plant or gas pipeline - that is utilized in a given period of time.

Load Management:
Steps taken to reduce power demand at peak load times or to shift some of it to off-peak times. This may be with reference to peak hours, peak days or peak seasons. The main thing affecting electric peaks is air-conditioning usage, which is, therefore, a prime target for load management efforts. Load management may be pursued by persuading consumers to modify behavior or by using equipment that regulates some electric consumption.

Loading Factor: Ratio of actual electricity consumed and total potential consumption. Used when analyzing electricity consumption in a large population. A loading factor of 0.5 means that 50% of homes are consuming all of the electricity they are able or that, on average, all of the homes are only consuming 50% of the power they have the potential to consume.

Lockbar: An optional feature of front-load containers. The lock bar allows a customer to lock the container. When the container is emptied, and the container is raised up and over the truck, gravity causes the bar to drop allowing the container to be emptied.

Loop Flow:
The difference between scheduled and actual power flows on electric transmission lines.

Losses (Electric Utility):
Electric energy or capacity that is wasted in the normal operation of a power system. Some kilowatt-hours are lost in the form of waste heat in electrical apparatus such as substation conductors. LINE LOSSES are kilowatts or kilowatt-hours lost in transmission and distribution lines under certain conditions.

Low Density Polyethylene (LOPE): Plastic material used for both rigid containers and plastic film applications.

Low-E: A special coating that reduces the emissivity of a window assembly, thereby reducing the heat transfer through the assembly.

Low Emission Vehicle (LEV): A vehicle certified by the California Air Resources Board to have emissions from zero to 50,000 miles no higher than 0.075 grams/mile (g/mi) of non-methane organic gasses, 3.4 g/mi of carbon monoxide, and 0.2 g/mi of nitrogen oxides. Emissions from 50,000 to 100,000 miles may be slightly higher.

Low Level Radioactive Waste (LLRW): Wastes less hazardous than most of those associated with a nuclear reactor; generated by hospitals, research laboratories, and certain industries. The Department of Energy, Nuclear Regulatory Commission, and EPA share responsibilities for managing them.

Low NOx Burners: One of several combustion technologies used to reduce emissions of Nitrogen Oxides (NOx).

Low Sulfur – Coal: Coal having one percent or less of sulfur by weight.

Low Sulfur – Oil:
Oil having one percent or less of sulfur by weight.

Lower Detection Limit: The smallest signal above background noise an instrument can reliably detect.

Lower Explosive Limit (LEL): The concentration of a compound in air below which the mixture will not catch on fire.

Lowest Acceptable Daily Dose:
The largest quantity of a chemical that will not cause a toxic effect, as determined by animal studies.

Lowest Achievable Emission Rate:
Under the Clean Air Act, the rate of emissions that reflects (1) the most stringent emission limitation in the implementation plan of any state for such source unless the owner or operator demonstrates such limitations are not achievable; or (2) the most stringent emissions limitation achieved in practice, whichever is more stringent. A proposed new or modified source may not emit pollutants in excess of existing new source standards.

Lowest Observed Adverse Effect Level (LOAEL): The lowest level of a stressor that causes statistically and biologically significant differences in test samples as compared to other samples subjected to no stressor.

Lumen: A measure of the amount of light available from a light source equivalent to the light emitted by one candle.

A measure of the efficacy of a light fixture; the number of lumens output per watt of power consumed.

Lumen Maintenance Control:
An electrical control device designed to vary the electrical consumption of a lighting system in order to maintain a specified illumination level.

Luminaire: A complete lighting unit consisting of a lamp or lamps together with the parts designed to distribute the light, to position and protect the lamps and to connect the lamps to the power supply.

LUX: A unit of illumination equal to the direct illumination on a surface that is everywhere one meter from a uniform point source of one candle; a unit of illumination that is equal to one lumen per square meter.

M85: A blend of 85 percent methanol and 15 percent unleaded regular gasoline, used as a motor fuel.

M100: 100 percent (neat) methanol used as a motor fuel in dedicated methanol vehicles, such as some heavy-duty truck engines.

Macropores: Secondary soil features such as root holes or desiccation cracks that can create significant conduits for movement of NAPL and dissolved contaminants, or vapour-phase contaminants.

Magma: The molten rock and elements that lie below the earth's crust. The heat energy can approach 1,000 degrees Fahrenheit and is generated directly from a shallow molten magma resource and stored in adjacent rock structures. To extract energy from magma resources requires drilling near or directly into a magma chamber and circulating water down the well in a convection- type system. California has two areas that may be magma resource sites: the Mono- Long Valley Caldera and Coso Hot Springs Known Geothermal Resource Areas.

Magnetic Separation: Use of magnets to separate ferrous materials from mixed municipal waste stream.

Magneto Hydro Dynamics (MHD):
A means of producing electricity directly by moving liquids or gasses through a magnetic field.

Major Marketer:
Any person who sells natural gas or oil in amounts determined by the commission as having a major effect on energy supplies.

Major Modification:
This term is used to define modifications of major stationary sources of emissions with respect to Prevention of Significant Deterioration and New Source Review under the Clean Air Act.

Major Natural Gas Producer:
Any person who produces natural gas in amounts determined by the commission as having a major effect on energy supplies.

Major Oil Producer:
Means any person who produces oil in the amount determined by the commission as having a major effect on energy supplies.

Major Stationary Sources: Term used to determine the applicability of Prevention of Significant Deterioration and new source regulations. In a nonattainment area, any stationary pollutant source with the potential to emit more than 100 tons per year is considered a major stationary source. In PSD areas the cutoff level may be either 100 or 250 tons, depending upon the source.

Man-Made (Anthropogenic) Beta Particle and Photon Emitters:
All radio-nuclides emitting beta particles and/or photons listed in Maximum Permissible Body Burdens and Maximum Permissible Concentrations of Radio-nuclides in Air and Water for Occupational Exposure.

Managerial Controls: Methods of nonpoint source pollution control based on decisions about managing agricultural wastes or application times or rates for agrochemicals.

Mandatory Recycling:
Programs which by law require consumers to separate trash so that some or all recyclable materials are recovered for recycling rather than going to landfills.

Manual landfill:
A landfill in which most operations are carried out without the use of mechanized equipment.

Manual Separation:
Hand sorting of recyclable or compostable materials in waste.

Manufactured Gas:
Gas produced by certain processes from oil, coal or coke.

Manufacturer's Formulation:
A list of substances or component parts as described by the maker of a coating, pesticide, or other product containing chemicals or other substances.

Manufacturing Use Product: Any product intended (labeled) for formulation or repackaging into other pesticide products.

Margin of Safety:
Maximum amount of exposure producing no measurable effect in animals (or studied humans) divided by the actual amount of human exposure in a population.

Margin of Exposure (MOE):
The ratio of the no-observed adverse-effect-level to the estimated exposure dose.

Marginal Cost:
The sum that has to be paid the next increment of the product of service. The marginal cost of electricity is the price to be paid for kilowatt-hours above and beyond those supplied by presently available generating capacity.

Marine Sanitation Device:
Any equipment or process installed on board a vessel to receive, retain, treat, or discharge sewage.

Market-Based Price:
A price set by the mutual decisions of many buyers and sellers in a competitive market.

Market Clearing Price: The price at which supply equals demand. The Day Ahead and Hour Ahead Markets.

Market Participant (MP): An entity, including a Scheduling Coordinator, who participates in the energy marketplace through the buying, selling, transmission, or distribution of energy or ancillary services into, out of, or through the ISO-controlled grid.

Market Waste:
Primarily organic waste, such as leaves, skins, and unsold food, discarded at or near food markets.

Marketer: An agent for generation projects who markets power on behalf of the generator. The marketer may also arrange transmission, firming or other ancillary services as needed. Though a marketer may perform many of the same functions as a broker, the difference is that a marketer represents the generator while a broker acts as a middleman.

Marginal Cost: In the utility context, the cost to the utility of providing the next (marginal)kilowatt-hour of electricity, irrespective of sunk costs.

A type of wetland that does not accumulate appreciable peat deposits and is dominated by herbaceous vegetation. Marshes may be fresh or saltwater, tidal or non-tidal.

Marsh Gas: A common term for gas that bubbles to the surface of the water in a marsh or swamp. It is colorless, odorless and can be explosive.

Mass-Burn: A type of combustion process in which solid waste is burned without sorting or processing being done at the facility.

Mass-Burn Incinerator: A type of incinerator in which solid waste is burned without prior sorting or processing.

Material Category: In the asbestos program, the broad classification of materials into thermal surfacing insulation, surfacing material, and miscellaneous material.

Material Type: Classification of suspect material by its specific use or application; e.g., pipe insulation, fireproofing, and floor tile.

Materials Recovery:
Operation consisting of collecting and/or sorting waste with a view to recycling the goods and materials it contains.

Materials Recovery Facility (MRF):
A facility that processes residentially collected mixed recyclables into new products available for market.

Materials Recovery Facility (MRF):
Line of business where recyclable material is processed, separated, and sold. This is a facility where recyclable materials are sorted and processed for sale. This process includes separating recyclable materials (manually or by machine) according to type, and baling or otherwise preparing the separated material for sale. Operating costs and revenues for MRF's are accounted for as a separate line of business.

Material Safety Data Sheet (MSDS):
A compilation of information required under the OSHA hazard communication standard, including a listing of hazardous chemicals, health and physical hazards, exposure limits and handling precautions.

Maximum Acceptable Toxic Concentration: For a given ecological effects test, the range (or geometric mean) between the No Observable Adverse Effect Level and the Lowest Observable Adverse Effects Level.

Maximum Available Control Technology (MACT): The emission standard for sources of air pollution requiring the maximum reduction of hazardous emissions, taking cost and feasibility into account. Under the Clean Air Act Amendments of 1990, the MACT must not be less than the average emission level achieved by controls on the best performing 12 percent of existing sources, by category of industrial and utility sources.

Maximum Contaminant Level: The maximum permissible level of a contaminant in water delivered to any user of a public system. MCLs are enforceable standards.

Maximum Contaminant Level Goal (MCLG):
Under the Safe Drinking Water Act, a non-enforceable concentration of a drinking water contaminant, set at the level at which no known or anticipated adverse effects on human health occur and which allows an adequate safety margin. The MCLG is usually the starting point for determining the regulated Maximum Contaminant Level.

Maximum Exposure Range:
Estimate of exposure or dose level received by an individual in a defined population that is greater than the 98th percentile dose for all individuals in that population, but less than the exposure level received by the person receiving the highest exposure level.

Maximum Residue Level:
Comparable to a U.S. tolerance level, the Maximum Residue Level the enforceable limit on food pesticide levels in some countries. Levels are set by the Codex Alimentarius Commission, a United Nations agency managed and funded jointly by the World Health Organization and the Food and Agriculture Organization.

Maximum Tolerated Dose:
The maximum dose that an animal species can tolerate for a major portion of its lifetime without significant impairment or toxic effect other than carcinogenicity.

MCF: One thousand cubic feet or natural gas, having an energy value of one million Btu. A typical home might use six MCF in a month.

Measure of Effect/ Measurement Endpoint: A measurable characteristic of the ecological entity that can be related to an assessment endpoint; e.g. a laboratory test for eight species meeting certain requirements may serve as a measure of effect for an assessment endpoint, such as survival of fish, aquatic, invertebrate or algal species under acute exposure.

Measure of Exposure:
A measurable characteristic of a stressor (such as the specific amount of mercury in a body of water) used to help quantify the exposure of an ecological entity or individual organism.

Mechanical Aeration: Use of mechanical energy to inject air into the water to cause a waste stream to absorb oxygen.

Mechanical Separation: Using mechanical means to separate waste into various components.

Mechanical Turbulence:
Random irregularities of fluid motion in the air caused by buildings or other nonthermal, processes.

Media: Specific environments--air, water, soil--which are the subject of regulatory concern and activities.

Medical Waste: Any solid waste generated in the diagnosis, treatment, or immunization of human beings or animals, in research pertaining thereto, or in the production or testing of biologicals, excluding hazardous waste identified or listed under 40 CFR Part 261 or any household waste as defined in 40 CFR Sub-section 261.4 (b)(1).

Medical Waste: Medical waste is generated by hospitals and healthcare professionals. It includes syringes, needles, and other sharp instruments. Under no circumstances can these be put in conventional waste bins. Medical waste must be disposed of in compliance with national regulations.

Medium-size Water System:
A water system that serves 3,300 to 50,000 customers.

Megawatt (MW):
One-thousand kilowatts (1,000 kW) or one million (1,000,000) watts. One megawatt is enough electrical capacity to power 1,000 average homes. That number fluctuates because electrical demand changes based on the season, the time of day, and other factors.

Megawatt Hour (MWh): One-thousand kilowatt-hours, or an amount of electrical energy that would supply 1,370 typical homes for one month.

Meniscus: The curved top of a column of liquid in a small tube.

Mercury (Hg): Heavy metal that can accumulate in the environment and is highly toxic if breathed or swallowed.

Mesotrophic: Reservoirs and lakes which contain moderate quantities of nutrients and are moderately productive in terms of aquatic animal and plant life.

Metabolites: Any substances produced by biological processes, such as those from pesticides.

The middle layer of a thermally stratified lake or reservoir. In this layer, there is a rapid decrease in temperature with depth. It is also called thermocline.

Methane (CH4):
A colorless, non-poisonous, flammable gas created by anaerobic decomposition of organic compounds. A major component of natural gas used in the home. The simplest of hydrocarbons and the principal constituent of natural gas. Pure methane has a heating value of 1,1012 Btu per standard cubic foot.

Methane: A light hydrocarbon that is the main component of natural gas and marsh gas. It is the product of the anaerobic decomposition of organic matter, enteric fermentation in animals and is one of the greenhouse gasses. The chemical formula is CH4.

Methane Gas Plant:
A plant where methane gas (generated from decomposing solid waste) is collected and transported to a gas-processing facility at the landfill site. Once processed, the methane gas is sold directly to industrial users or to an Affiliate of WMI to use as a fuel to power electricity generators.

Methane Production: A natural method for treating organic waste. It leads to the production of gas (biogas) that can be converted into energy. The gas comes from the biological decomposition of organic matter in an air-deprived environment (known as "anaerobic digestion" because it is without oxygen). A digestate ("digested" waste) is also produced and can be used raw or after treatment (dewatering and composting, sanitization) as a compost. Organic waste, which has high water content and is highly biodegradable, is used primarily for methane production. Organic waste includes putrescible household waste, wastewater treatment plant sludge, oil, grease and night soil, some agrifood industry waste and some agricultural waste.

Methanol (also known as Methyl Alcohol, Wood Alcohol, CH3OH):
A liquid formed by catalytically combining carbon monoxide (CO) with hydrogen (H2) in a 1:2 ratio, under high temperature and pressure. Commercially it is typically made by steam reforming natural gas. Also formed in the destructive distillation of wood.

Methanol: An alcohol that can be used as an alternative fuel or as a gasoline additive. It is less volatile than gasoline; when blended with gasoline it lowers the carbon monoxide emissions but increases hydrocarbon emissions. Used as pure fuel, its emissions are less ozone-forming than those from gasoline. Poisonous to humans and animals if ingested.

Methoxychlor: Pesticide that causes adverse health effects in domestic water supplies and is toxic to freshwater and marine aquatic life.

Methyl Orange Alkalinity:
A measure of the total alkalinity in a water sample in which the color of methyl orange reflects the change in level.

Methyl Tertiary Butyl Ether (MTBE):
An ether manufactured by reacting methanol and isobutylene. The resulting ether has a high octane and low volatility. MTBE is a fuel oxygenate and is permitted in unleaded gasoline up to a level of 15 percent. It is one of the primary ingredients in reformulated gasoline. A clean burning oxygenates with high octane and low volatility added to unleaded gasoline to reduce carbon monoxide emissions.

Microbial Growth: The amplification or multiplication of microorganisms such as bacteria, algae, diatoms, plankton, and fungi.

Microbial Pesticide:
A microorganism that is used to kill a pest, but is of minimum toxicity to humans.

1. Localized climate conditions within an urban area or neighborhood. 2. The climate around a tree or shrub or a stand of trees.

Well-defined surroundings such as the home, office, or kitchen that can be treated as uniform in terms of stressor concentration.

Electromagnetic radiation with wavelengths of a few centimeters. It falls between infrared and radio wavelengths on the electromagnetic spectrum. The radio wave beam can deliver electrical energy over long distances.

Million-Gallons Per Day (MGD): A measure of water flow.

Minimum Generation:
Generally, the required minimum generation level of a utility systems thermal units. Specifically, the lowest level of operation of oil-fired and gas-fired units at which they can be currently available to meet peak load needs.

A comprehensive program to minimize or eliminate wastes, usually applied to wastes at their point of origin.

Mining of an Aquifer:
Withdrawal over a period of time of ground water that exceeds the rate of recharge of the aquifer.

Mining Waste: Residues resulting from the extraction of raw materials from the earth.

Miscible Liquids: Two or more liquids that can be mixed and will remain mixed under normal conditions.

Missed Detection:
The situation that occurs when a test indicates that a tank is "tight" when in fact it is leaking.

Liquid particles measuring 40 to 500 micrometers (pm), are formed by condensation of vapor. By comparison, fog particles are smaller than 40 micrometers (pm).

Mitigation: Measures taken to reduce adverse impacts on the environment.

Mixed Glass:
Recovered container glass not sorted into categories (e.g. color, grade).

Mixed Liquor: A mixture of activated sludge and water containing organic matter undergoing activated sludge treatment in an aeration tank.

Mixed Metals: Recovered metals not sorted into categories such as aluminum, tin, or steel cans or ferrous or non-ferrous metals.

Mixed Municipal Waste: Solid waste that has not been sorted into specific categories (such as plastic, glass, yard trimmings, etc.)

Mixed Paper: Recovered paper not sorted into categories such as old magazines, old newspapers, old corrugated boxes, etc.

Mixed Plastic:
Recovered plastic unsorted by category.

Mobile Incinerator Systems: Hazardous waste incinerators that can be transported from one site to another.

Mobile Source:
Any non-stationary source of air pollution such as cars, trucks, motorcycles, buses, airplanes, and locomotives.

Modular Incinerator: A relatively small type of prefabricated solid waste combustion unit.

Moisture Content:
1.The amount of water lost from soil upon drying to a constant weight expressed as the weight per unit of dry soil or as the volume of water per unit bulk volume of the soil. For a fully saturated medium, moisture content indicates the porosity. 2. Water equivalent of snow on the ground; an indicator of snowmelt flood potential.

The smallest division of a compound that still retains or exhibits all the properties of the substance.

Molten Salt Reactor:
A thermal treatment unit that rapidly heats waste in a heat-conducting fluid bath of carbonate salt.

Monitoring: Periodic or continuous surveillance or testing to determine the level of compliance with statutory requirements and/or pollutant levels in various media or in humans, plants, and animals.

Monitoring Well:
1. A well used to obtain water quality samples or measure groundwater levels. 2. A well drilled at a hazardous waste management facility or Superfund site to collect ground-water samples for the purpose of physical, chemical, or biological analysis to determine the amounts, types, and distribution of contaminants in the groundwater beneath the site.

Monoclonal Antibodies (Also called MABs and MCAs):
1. Man-made (anthropogenic) clones of a molecule, produced in quantity for medical or research purposes. 2. Molecules of living organisms that selectively find and attach to other molecules to which their structure conforms exactly. This could also apply to equivalent activity by chemical molecules.

Monofill: A landfill intended for one type of waste only.

Lakes and reservoirs which are relatively deep, do not freeze over during winter, and undergo a single stratification and mixing cycle during the year (usually in the fall).

The only seller with control over market sales.

Monopsony: The only buyer with control over market purchases.

Montreal Protocol: Treaty, signed in 1987, governs stratospheric ozone protection and research, and the production and use of ozone-depleting substances. It provides for the end of production of ozone-depleting substances such as CFCS. Under the Protocol, various research groups continue to assess the ozone layer. The Multilateral Fund provides resources to developing nations to promote the transition to ozone-safe technologies.

Most Probable Number: An estimate of microbial density per unit volume of the water sample, based on probability theory.

Muck Soils:
Earth made from decaying plant materials.

Mudballs: Round material that forms in filters and gradually increases in size when not removed by backwashing.

Mulch: A layer of material (wood chips, straw, leaves, etc.) placed around plants to hold moisture, prevent weed growth, and enrich or sterilize the soil.

Multiple Use: Use of land for more than one purpose; e.g., grazing of livestock, watershed and wildlife protection, recreation, and timber production. Also applies to use of bodies of water for recreational purposes, fishing, and water supply.

Municipal Discharge:
Discharge of effluent from waste water treatment plants which receive waste water from households, commercial establishments, and industries in the coastal drainage basin. Combined sewer/separate storm overflows are included in this category.

Municipal Sewage: Wastes (mostly liquid) originating from a community; may be composed of domestic wastewaters and/or industrial discharges.

Municipal Sludge: Semi-liquid residue remaining from the treatment of municipal water and wastewater.

Municipal Solid Waste: Common garbage or trash generated by industries, businesses, institutions, and homes.

Municipal Solid Waste (MSW):
All solid waste generated in an area except industrial and agricultural wastes, typically from residences, commercial or retail establishments. Sometimes includes construction and demolition debris and other special wastes that may enter the municipal waste stream. The EPA (1998c) defined municipal solid waste as "a subset of solid waste and as durable goods (e.g., appliances, tyres, batteries), non-durable goods (e.g., newspapers, books, magazines), containers and packaging, food wastes, yard trimmings, and miscellaneous organic wastes from residential, commercial and industrial non-process sources.

Municipal Solid Waste Collection:
The process of picking up wastes from residences, businesses, or a collection point, loading them into a vehicle, and transporting them to a processing, transfer, or disposal site.

Municipal Solid Waste Management (MSWM): Planning and implementation of systems to handle MSW.

Municipal Waste: Household and other waste collected by municipalities. Its great diversity and the leeway left to municipalities to collect or not certain types of waste explains the lack of comprehensive figures in this area.

Municipal Waste Combustor: Combustion facility that uses MSW as its primary, i.e., at least 70%, fuel source.

Municipal Waste Flue Gas Treatment:
The residue from the treatment of municipal waste incineration flue gasses is a solid residue collected after chemically treating flue gas to reduce pollution. The treatment is based on neutralization combined with filtration. The target pollutants are acid gasses and particulate matter, plus heavy metals, nitrogen oxides, and dioxins, which are treated by supplementary processes. The neutralizing reagents can be injected dry in the form of powder (lime or sodium bicarbonate), by semi-wet means (pulverized milk of lime), or by wet means in a soda washing column. These processes generate residual products, mainly comprised of fly ash. Flue gas treatment residue is stabilized before being stored in authorized landfills. These processes are used to treat over 98% of municipal waste incineration flue gas.

Municipalization: The process by which a municipal entity assumes responsibility for supplying utility service to its constituents. In supplying electricity, the municipality may generate and distribute the power or purchase wholesale power from other generators and distribute it.

Municipal Utility: A provider of utility services owned and operated by a municipal government.

Mutagen/Mutagenicity: An agent that causes a permanent genetic change in a cell other than that which occurs during normal growth. Mutagenicity is the capacity of a chemical or physical agent to cause such permanent changes.

National Estuary Program: A program established under the Clean Water Act Amendments of 1987 to develop and implement conservation and management plans for protecting estuaries and restoring and maintaining their chemical, physical, and biological integrity, as well as controlling point and nonpoint pollution sources.

National Municipal Plan:
A policy created in 1984 by EPA and the states in 1984 to bring all publicly owned treatment works (POTWs) into compliance with Clean Water Act requirements.

National Oil and Hazardous Substances Contingency Plan (NOHSCP/NCP):
The federal regulation that guides the determination of the sites to be corrected under both the Superfund program and the program to prevent or control spills into surface waters or elsewhere.

National Pollutant Discharge Elimination System (NPDES):
A provision of the Clean Water Act which prohibits the discharge of pollutants into waters of the United States unless a special permit is issued by EPA, a state, or, where delegated, a tribal government on an Indian reservation.

National Priorities List (NPL): EPA's list of the most serious uncontrolled or abandoned hazardous waste sites identified for possible long-term remedial action under Superfund. The list is based primarily on the score a site receives from the Hazard Ranking System. EPA is required to update the NPL at least once a year. A site must be on the NPL to receive money from the Trust Fund for remedial action.

Natural Gas: Hydrocarbon gas found in the earth, composed of methane, ethane, butane, propane and other gasses.

Natural Gas Vehicle: Vehicles that are powered by compressed or liquefied natural gas.

Natural Gasoline: A mixture of liquids extracted from natural gas and suitable for blending with ordinary oil-derived gasoline.

Natural Monopoly: A situation where one firm can produce a given level of output at a lower total cost than can any combination of multiple firms. Natural monopolies occur in industries which exhibit decreasing average long-run costs due to size (economies of scale). According to economic theory, a public monopoly governed by regulation is justified when an industry exhibits natural monopoly characteristics.

Navigable Waters: Traditionally, waters sufficiently deep and wide for navigation by all, or specified vessels; such waters in the United States come under federal jurisdiction and are protected by certain provisions of the Clean Water Act.

NCSL(The National Conference of State Legislatures): A national advisory council which provides services to state legislatures "by bringing together information from all states to forge workable answers to complex policy questions."

Necrosis: Death of plant or animal cells or tissues. In plants, necrosis can discolor stems or leaves or kill a plant entirely.

Nematocide: A chemical agent which is destructive to nematodes.

Method of measuring turbidity in a water sample by passing light through the sample and measuring the amount of the light that is deflected.

Netting: A concept in which all emissions sources in the same area that owned or controlled by a single company are treated as one large source, thereby allowing flexibility in controlling individual sources in order to meet a single emissions standard.

Neutralization: Decreasing the acidity or alkalinity of a substance by adding alkaline or acidic materials, respectively.

Neutron: An uncharged particle found in the nucleus of every atom except that of hydrogen.

New Source Performance Standards (NSPS):
Uniform national EPA air emission and water effluent standards which limit the amount of pollution allowed from new sources or from modified existing sources.

New Source Review (NSR): A Clean Air Act requirement that State Implementation Plans must include a permit review that applies to the construction and operation of new and modified stationary sources in nonattainment areas to ensure attainment of national ambient air quality standards.

A unit of force. The amount of force it takes to accelerate one kilogram at one meter per second per second.

NIMBY: "Not In My Back Yard." An expression of resident opposition to the siting of a solid waste facility based on the particular location proposed.

Nitrate: A compound containing nitrogen that can exist in the atmosphere or as a dissolved gas in water and which can have harmful effects on humans and animals. Nitrates in water can cause severe illness in infants and domestic animals. A plant nutrient and inorganic fertilizer, nitrate is found in septic systems, animal feed lots, agricultural fertilizers, manure, industrial waste waters, sanitary landfills, and garbage dumps.

Nitric Oxide (NO): A gas formed by combustion under high temperature and high pressure in an internal combustion engine; it is converted by sunlight and photochemical processes in ambient air to nitrogen oxide. NO is a precursor of ground-level ozone pollution or smog.

Nitrification: The process whereby ammonia in wastewater is oxidized to nitrite and then to nitrate by bacterial or chemical reactions.

Nitrilotriacetic Acid (NTA):
A compound now replacing phosphates in detergents.

Nitrite: 1. An intermediate in the process of nitrification. 2. Nitrous oxide salts used in food preservation.

Nitrogen Dioxide (NO2): The result of nitric oxide combining with oxygen in the atmosphere; major component of photochemical smog.

Nitrogen Oxide (NOx):
The result of photochemical reactions of nitric oxide in ambient air; major component of photochemical smog. The product of combustion from transportation and stationary sources and a major contributor to the formation of ozone in the troposphere and to acid deposition.

Nitrogen Oxides (NOx):
Emissions that contribute to the formation of smog.

Nitrogenous Wastes:
Animal or vegetable residues that contain significant amounts of nitrogen.

Nitrophenols: Synthetic organo pesticides containing carbon, hydrogen, nitrogen, and oxygen.

No Till: Planting crops without prior seedbed preparation, into an existing cover crop, sod, or crop residues, and eliminating subsequent tillage operations.

Noble Metal: Chemically inactive metal such as gold; does not corrode easily.

Noise: Product-level or product-volume changes occurring during a test that is not related to a leak but may be mistaken for one.

Non-Aqueous Phase Liquid (NAPL): Contaminants that remain undiluted as the original bulk liquid in the subsurface, e.g. spilled oil.

Non-Compliance Coal: Any coal that emits greater than 3.0 pounds of sulfur dioxide per million BTU when burned. Also known as high-sulfur coal.

Non-Contact Cooling Water: Water used for cooling which does not come into direct contact with any raw material, product, by-product, or waste.

Non-Conventional Pollutant:
Any pollutant not statutorily listed or which is poorly understood by the scientific community.

Non-Degradation: An environmental policy which disallows any lowering of naturally occurring quality regardless of pre-established health standards.

Non-Depletable Energy Sources: Energy which is not obtained from depletable energy sources.

Non-discharging Treatment Plant: A treatment plant that does not discharge treated wastewater into any stream or river. Most are pond systems that dispose of the total flow they receive by means of evaporation or percolation to groundwater, or facilities that dispose of their effluent by recycling or reuse (e.g. spray irrigation or groundwater discharge).

Non-Ferrous Metals: Nonmagnetic metals such as aluminum, lead, and copper. Products made all or in part from such metals include containers, packaging, appliances, furniture, electronic equipment, and aluminum foil.

Non-Firm Energy:
Electricity that is not required to be delivered or to be taken under the terms of an electric purchase contract.

Non-Friable Asbestos-Containing Materials:
Any material containing more than one percent asbestos (as determined by Polarized Light Microscopy) that, when dry, cannot be crumbled, pulverized or reduced to powder by hand pressure.

Non-Hazardous Industrial Waste:
All non-inert and non-hazardous waste generated by companies, manufacturers, retail outlets, self-employed tradesmen and service providers. It includes scrap iron and other metals, paper and cardboard, glass, textiles, wood, and plastics.

Non-ionizing Electromagnetic Radiation:
1. Radiation that does not change the structure of atoms but does heat tissue and may cause harmful biological effects. 2. Microwaves, radio waves, and low-frequency electromagnetic fields from high-voltage transmission lines.

Non-Methane Hydrocarbon (NMHC): The sum of all hydrocarbon air pollutants except methane; significant precursors to ozone formation.

Non-Methane Organic Gases (NMOG):
The sum of all organic air pollutants. Excluding methane; they account for aldehydes, ketones, alcohols, and other pollutants that are not hydrocarbons but are precursors of ozone.

Non-Point Sources:
Diffuse pollution sources (i.e. without a single point of origin or not introduced into a receiving stream from a specific outlet). The pollutants are generally carried off the land by storm water. Common non-point sources are agriculture, forestry, urban, mining, construction, dams, channels, land disposal, saltwater intrusion, and city streets.

Water that is unsafe or unpalatable to drink because it contains pollutants, contaminants, minerals, or infective agents.

Non-Renewable Energy: Sources of energy that cannot be replaced in a reasonable period of time. Fossil fuels (coal, petroleum, natural gas) are examples of non-renewable energy sources.

Non-Road Emissions
: Pollutants emitted by combustion engines on farm and construction equipment, gasoline-powered lawn and garden equipment, and power boats and outboard motors.

Oxides of nitrogen that are a chief component of air pollution that can be produced by the burning of fossil fuels. Also called nitrogen oxides.

Nitrogen oxides (NO (nitrogen oxide) and NO2 (nitrogen dioxide) act as indirect greenhouse gasses by producing the tropospheric greenhouse gas 'ozone' during their breakdown in the atmosphere.

Nuclear Energy: Power obtained by splitting heavy atoms (fission) or joining light atoms (fusion). A nuclear energy plant uses a controlled atomic chain reaction to produce heat. The heat is used to make steam run conventional turbine generators.

Nuclear Reactors and Support Facilities:
Uranium mills, commercial power reactors, fuel reprocessing plants, and uranium enrichment facilities.

Nuclear Regulatory Commission (NRC):
An independent federal agency that ensures that strict standards of public health and safety, environmental quality, and national security are adhered to by individuals and organizations possessing and using radioactive materials. The NRC is the agency that is mandated with licensing and regulating nuclear power plants in the United States. It was formally established in 1975 after its predecessor, the Atomic Energy Commission, was abolished.

Nuclear Winter: Prediction by some scientists that smoke and debris rising from massive fires of a nuclear war could block sunlight for weeks or months, cooling the earth's surface and producing climate changes that could, for example, negatively affect the world agricultural and weather patterns.

Nuclide: An atom characterized by the number of protons, neutrons, and energy in the nucleus.

Nug: A non-utility generator. A generation facility owned and operated by an entity who is not defined as a utility in that jurisdictional area.

Nutrient: Any substance assimilated by living things that promote growth. The term is generally applied to nitrogen and phosphorus in wastewater but is also applied to other essential and trace elements.

Nutrient Pollution:
Contamination of water resources by excessive inputs of nutrients. In surface waters, excess algal production is a major concern.

OAPEC: Acronym for Organization of Arab Petroleum Exporting Countries founded in 1968 for cooperation in economic and petroleum affairs.

Obligation To Serve: The obligation of a utility to provide electric service to any customer who seeks that service, and is willing to pay the rates set for that service. Traditionally, utilities have assumed the obligation to serve in return for an exclusive monopoly franchise.

Occupancy Sensor:
A control device that senses the presence of a person in a given space, commonly used to control lighting systems in buildings.

Ocean Discharge Waiver:
A variance from Clean Water Act requirements for discharges into marine waters.

Ocean Thermal Gradient (OTG):
Temperature differences between deep and surface water. Deep water is likely to be 25 to 45 degrees Fahrenheit colder. The term also refers to experimental technology that could use the temperature differences as a means to produce energy.

A rating scale used to grade gasoline as to its antiknock properties. Also any of several isometric liquid paraffin hydrocarbons, C8H18. Normal octane is a colorless liquid found in petroleum boiling at 124.6 degrees Celsius.

Octane Rating:
A measure of a gasoline's resistance to exploding too early in the engine cycle, which causes knocking. The higher the rating, the lower the chance of premature ignition.

Odor Threshold: The minimum odor of a water or air sample that can just be detected after successive dilutions with odorless water. It is also called threshold odor.

OECD Guidelines: Testing guidelines prepared by the Organization for Economic and Cooperative Development of the United Nations. They assist in the preparation of protocols for studies of toxicology, environmental fate, etc.

Off-Road: Any non-stationary device, powered by an internal combustion engine or motor, used primarily off the highways to propel, move, or draw persons or property, and used in any of the following applications: marine vessels, construction/farm equipment, locomotives, utility and lawn and garden equipment, off-road motorcycles, and off-highway vehicles.

Off-Site Facility: A hazardous waste treatment, storage or disposal area that is located away from the generating site.

Offsets: A concept whereby emissions from proposed new or modified stationary sources are balanced by reductions from existing sources to stabilize total emissions. Greenhouse gas reduction activities are undertaken to compensate for emissions elsewhere

Offstream Use:
Water withdrawn from surface or groundwater sources for use at another place.

A unit of measure of electrical resistance. One volt can produce a current of one ampere through a resistance of one ohm.

Oil and Gas Waste:
Gas and oil drilling muds, oil production brines, and other waste associated with exploration for, development and production of crude oil or natural gas.

Oil Desulfurization:
Widely used precombustion method for reducing sulfur dioxide emissions from oil-burning power plants. The oil is treated with hydrogen, which removes some of the sulfur by forming hydrogen sulfide gas.

Oil Fingerprinting:
A method that identifies sources of oil and allows spills to be traced to their source.

Oil Shale:
A type of rock containing organic matter that produces large amounts of oil when heated to high temperatures.

Oil Spill: An accidental or intentional discharge of oil which reaches bodies of water. Can be controlled by chemical dispersion, combustion, mechanical containment, and/or adsorption. Spills from tanks and pipelines can also occur away from water bodies, contaminating the soil, getting into sewer systems and threatening underground water sources.

A few sellers who exert market control over prices.

Oligotrophic Lakes: Deep clear lakes with few nutrients, little organic matter, and a high dissolved-oxygen level.

On-Site Facility: A hazardous waste treatment, storage or disposal area that is located on the generating site.

Onboard Controls:
Devices placed on vehicles to capture gasoline vapor during refueling and route it to the engines when the vehicle is starting so that it can be efficiently burned.

Onconogenicity: The capacity to induce cancer.

One-hit Model: A mathematical model based on the biological theory that a single "hit" of some minimum critical amount of a carcinogen at a cellular target such as DNA can start an irreversible series events leading to a tumor.

Opacity: The amount of light obscured by particulate pollution in the air; clear window glass has zero opacity, a brick wall is 100 percent opaque. Opacity is an indicator of changes in performance of particulate control systems.

OPEC: Acronym for Organization of Petroleum Exporting Countries founded in 1960 for unify and coordinate petroleum polices of the members. Headquarters is in Vienna, Austria.

Open Burning: Uncontrolled fires in an open dump.

Open Dump: An uncovered site used for disposal of waste without environmental controls.

Open Dump:
An unplanned "landfill" that incorporates few if any of the characteristics of a controlled landfill. There is typically no leachate control, no access control, no cover, no management, and many waste pickers.

Operable Unit: Term for each of a number of separate activities undertaken as part of a Superfund site cleanup. A typical operable unit would be the removal of drums and tanks from the surface of a site.

Optimal Corrosion Control Treatment:
An erosion control treatment that minimizes the lead and copper concentrations at users' taps while also ensuring that the treatment does not cause the water system to violate any national primary drinking water regulations.

An act, process or methodology of making something (as a design, system or decision) as fully perfect, functional or effective as possible.

Options: An option is a contractual agreement that gives the holder the right to buy (call option) or sell (put option) a fixed quantity of a security or commodity (for example, a commodity or commodity futures contract), at a fixed price, within a specified period of time. May either be standardized, exchange-traded, and government regulated, or over-the-counter customized and non-regulated.

Oral Toxicity: Ability of a pesticide to cause injury when ingested.

Organic: 1. Referring to or derived from living organisms. 2. In chemistry, any compound containing carbon.

Organic Chemicals/Compounds:
Naturally occurring (animal or plant-produced or synthetic) substances containing mainly carbon, hydrogen, nitrogen, and oxygen.

Organic Matter:
Carbonaceous waste contained in plant or animal matter and originating from domestic or industrial sources.

Organic Matter:
Organic matter in the soil is made up of living organisms, plant and animal residue, and decomposing products. In general, it only represents between 0.5% and 10% of the soil's mass. Organic matter disappears as a result of erosion, clearing or natural oxidation. However, it boosts fertility and plays an essential role in the stability of the ecosystem. It, therefore, fulfills important environmental functions (preserving soil, protecting water resources and trapping carbon).

Organic Soil Improver:
A stable, dry product with high agricultural value. Organic soil improvers are generated by composting organic waste, which includes food waste, green waste, and wastewater treatment sludge. Rich in humus, it is applied to land to improve various soil properties:

physical: stabilization, aeration, and erosion resistance;

chemical: fertilization and addition of trace elements;

biological: strengthening of plant resistance and the soil's

biological activity.

Organic Waste:
Technically, waste containing carbon, including paper, plastics, wood, food wastes, and yard wastes. In practice in MSWM, the term is often used in a more restricted sense to mean a material that is more directly derived from plant or animal sources, and which can generally be decomposed by microorganisms.

Organism: Any form of animal or plant life.

Organophosphates: Pesticides that contain phosphorus; short-lived, but some can be toxic when first applied.

A substance that easily combines with organic compounds.

Organotins: Chemical compounds used in anti-foulant paints to protect the hulls of boats and ships, buoys, and pilings from marine organisms such as barnacles.

Orientation: The position of a building relative to the points of a compass.

Original Equipment Manufacturer (OEM):
Refers to the manufacturers of complete vehicles or heavy-duty engines, as contrasted with remanufacturers, converters, retrofitters, up-fitters, and re-powering or rebuilding contractors who are overhauling engines, adapting or converting vehicles or engines obtained from the OEMs, or exchanging or rebuilding engines in existing vehicles.

Original Generation Point:
Where regulated medical or other material first becomes waste.

The passage of a liquid from a weak solution to a more concentrated solution across a semi permeable membrane that allows passage of the solvent (water) but not the dissolved solids.

Other Ferrous Metals: Recyclable metals from strapping, furniture, and metal found in tires and consumer electronics but does not include metals found in construction materials or cars, locomotives, and ships.

Other Glass:
Recyclable glass from furniture, appliances, and consumer electronics. It does not include glass from transportation products (cars trucks or shipping containers) and construction or demolition debris.

Other Nonferrous Metals:
Recyclable nonferrous metals such as lead, copper, and zinc from appliances, consumer electronics, and non-packaging aluminum products. It does not include nonferrous metals from industrial applications and construction and demolition debris.

Other Plastics: Recyclable plastic from appliances, eating utensils, plates, containers, toys, and various kinds of equipment. It does not include heavy-duty plastics such as yielding materials.

Other Solid Waste: Recyclable nonhazardous solid wastes, other than municipal solid waste, covered under Subtitle D of RARA.

Other Wood:
Recyclable wood from furniture, consumer electronics cabinets, and other non-packaging wood products. Does not include lumber and tree stumps recovered from construction and demolition activities, and industrial process waste such as shavings and sawdust.

Outage (Electric Utility):
An interruption of electric service that is temporary (minutes or hours) and affects a relatively small area (buildings or city blocks).

Outdoor Air Supply:
Air brought into a building from outside.

Outer Continental Shelf (OCS): The submerged lands extending from the out limit of the historic territorial sea (typically three miles) to some undefined outer limit, usually a depth of 600 feet. In the United States, this is the portion of the shelf under federal jurisdiction.

Outfall: The place where effluent is discharged into receiving waters.

Outside Air: Air taken from outdoors and not previously circulated through the HVAC system.

Over Generation: A condition that occurs when total PX participant demand is less than or equal to the sum of regulatory must-take generation, regulatory must-run generation, and reliability must-run generation.

Overburden: Rock and soil cleared away before mining.

Overdraft: The pumping of water from a groundwater basin or aquifer in excess of the supply flowing into the basin; results in a depletion or "mining" of the groundwater in the basin.

Overfire Air: Air forced into the top of an incinerator or boiler to fan the flames.

Overflow Rate: One of the guidelines for the design of the settling tanks and clarifiers in a treatment plant; used by plant operators to determine if tanks and clarifiers are over or under-used.

Any horizontal projection that serves as a shading element for a window.

Overland Flow:
A land application technique that cleanses waste water by allowing it to flow over a sloped surface. As the water flows over the surface, contaminants are absorbed and the water is collected at the bottom of the slope for reuse.

Oversized Regulated Medical Waste:
Medical waste that is too large for plastic bags or standard containers.

Overturn: One complete cycle of top to the bottom mixing of previously stratified water masses. This phenomenon may occur in spring or fall, or after storms, and results in uniformity of chemical and physical properties of water at all depths.

A collective term for some of the primary constituents of photochemical smog.

Oxidation: The chemical addition of oxygen to break down pollutants or organic waste; e.g., destruction of chemicals such as cyanides, phenols, and organic sulfur compounds in sewage by bacterial and chemical means.

Oxidation Pond: A man-made (anthropogenic) body of water in which waste is consumed by bacteria, used most frequently with other waste-treatment processes; a sewage lagoon.
Oxidation-Reduction Potential: The electric potential required to transfer electrons from one compound or element (the oxidant) to another compound (the reductant); used as a qualitative measure of the state of oxidation in water treatment systems.

Oxygenate: A term used in the petroleum industry to denote octane components containing hydrogen, carbon, and oxygen in their molecular structure. It includes ethers such as MTBE and ETBE and alcohols such as ethanol or methanol. The oxygenate is a prime ingredient in reformulated gasoline. The increased oxygen content given by oxygenates promotes a complete combustion, thereby reducing tailpipe emissions.

Oxygenated Fuels: Gasoline which has been blended with alcohols or ethers that contain oxygen in order to reduce carbon monoxide and other emissions.

Oxygenated Solvent:
An organic solvent containing oxygen as part of the molecular structure. Alcohols and ketones are oxygenated compounds often used as paint solvents.

Application of ozone to water for disinfection or for taste and odor control. The Ozonator is the device that does this.

Ozone: A kind of oxygen that has three atoms per molecule instead of the usual two. Ozone is a poisonous gas, but the ozone layer in the upper atmosphere shields life on earth from deadly ultraviolet radiation from space. The molecule contains three oxygen atoms (O3).

Ozone (O3): Found in two layers of the atmosphere, the stratosphere, and the troposphere. In the stratosphere (the atmospheric layer 7 to 10 miles or more above the earth's surface) ozone is a natural form of oxygen that provides a protective layer shielding the earth from ultraviolet radiation. In the troposphere (the layer extending up 7 to 10 miles from the earth's surface), ozone is a chemical oxidant and major component of photochemical smog. It can seriously impair the respiratory system and is one of the widest spread of all the criteria pollutants for which the Clean Air Act required EPA to set standards. Ozone in the troposphere is produced through complex chemical reactions of nitrogen oxides, which are among the primary pollutants emitted by combustion sources; hydrocarbons, released into the atmosphere through the combustion, handling and processing of petroleum products; and sunlight.

Ozone Depleting Substance (ODS):
Substances that release chlorine or bromine atoms when they break down which deplete the ozone.

Ozone Depletion: Destruction of the stratospheric ozone layer which shields the earth from ultraviolet radiation harmful to life. This destruction of ozone is caused by the breakdown of certain chlorine and/or bromine containing compounds (chlorofluorocarbons or halons), which break down when they reach the stratosphere and then catalytically destroy ozone molecules.

Ozone Hole: A thinning break in the stratospheric ozone layer. Designation of the amount of such depletion as an "ozone hole" is made when the detected amount of depletion exceeds fifty percent. Seasonal ozone holes have been observed over both the Antarctic and Arctic regions, part of Canada, and the extreme north-eastern United States.

Ozone Layer: The protective layer in the atmosphere, about 15 miles above the ground, that absorbs some of the sun's ultraviolet rays, thereby reducing the amount of potentially harmful radiation that reaches the earth's surface.

Packed Bed Scrubber: An air pollution control device in which emissions pass through alkaline water to neutralize hydrogen chloride gas.

Packed Tower: A pollution control device that forces dirty air through a tower packed with crushed rock or wood chips while liquid is sprayed over the packing material. The pollutants in the air stream either dissolve or chemically react with the liquid.

Packer: An inflatable gland, or balloon, used to create a temporary seal in a borehole, probe hole, well, or drive casing. It is made of rubber or non-reactive materials.

Palatable Water: Water, at a desirable temperature, that is free from objectionable tastes, odors, colors, and turbidity.

Pandemic: A widespread epidemic throughout an area, nation or the world.

Paper: In the recycling business, refers to products and materials, including newspapers, magazines, office papers, corrugated containers, bags and some paperboard packaging that can be recycled into new paper products.

Paper Processor/Plastics Processor: The intermediate facility where recovered paper or plastic products and materials are sorted, decontaminated, and prepared for final recycling.

Parallel grid mode: This is where the Cogeneration unit runs in parallel with the grid

Parallel Path Flow: As defined by NERC, this refers to the flow of electric power on an electric system's transmission facilities resulting from scheduled electric power transfers between two other electric systems. (Electric power flows on all interconnected parallel paths in amounts inversely proportional to each path's resistance.)

Parameter: A variable, measurable property whose value is a determinant of the characteristics of a system; e.g. temperature, pressure, and density are parameters of the atmosphere.

Paraquat: A standard herbicide used to kill various types of crops, including marijuana. Causes lung damage if smoke from the crop is inhaled.

Parshall Flume: Device used to measure the flow of water in an open channel.

Partial Load: An electrical demand that uses only part of the electrical power available.

Particle Count: Results of a microscopic examination of treated water with a special "particle counter" that classifies suspended particles by number and size.

Particulate: Fine solid particles of dust, spore, pollen, dander, skin flakes, mite allergens, cell debris, mold, mildew, mineral fibers or solids escaping from combustion processes that are small enough to become suspended in the air, and in some cases, small enough to be inhaled.

Particulate Loading: The mass of particulates per unit volume of air or water.

Particulate Matter (PM): Unburned fuel particles that form smoke or soot and stick to lung tissue when inhaled. A chief component of exhaust emissions from heavy-duty diesel engines.

Particulates: 1. Fine liquid or solid particles such as dust, smoke, mist, fumes, or smog, found in air or emissions. 2. Very small solids suspended in water; they can vary in size, shape, density and electrical charge and can be gathered together by coagulation and flocculation.

Partition Coefficient: Measure of the sorption phenomenon, whereby a pesticide is divided between the soil and water phase; also referred to as adsorption partition coefficient.

Parts Per Billion (ppb)/Parts Per Million (ppm): Units commonly used to express contamination ratios, as in establishing the maximum permissible amount of a contaminant in water, land, or air.

Passive Solar Energy: Use of the sun to help meet a building's energy needs by means of architectural design (such as the arrangement of windows) and materials (such as floors that store heat, or other thermal mass).

Passive Solar System:
A solar heating or cooling system that uses no external mechanical power to move the collected solar heat.

Passive Treatment Walls: Technology in which a chemical reaction takes place when contaminated ground water comes in contact with a barrier such as a limestone or a wall containing iron filings.

Pathogens: Microorganisms (e.g., bacteria, viruses, or parasites) that can cause disease in humans, animals, and plants.

Pathway: The physical course a chemical or pollutant takes from its source to the exposed organism.

Pay-As-You-Throw/Unit-Based Pricing: Systems under which residents pay for municipal waste management and disposal services by weight or volume collected, not a fixed fee.

PBR - Performance-Based Regulation: Any rate-setting mechanism which attempts to link rewards (generally profits) to desired results or targets. PBR sets rates, or components of rates, for a period of time-based on external indices rather than a utility's cost-of-service. Other definitions include light-handed regulation which is less costly and less subject to debate and litigation. A form of rate regulation which provides utilities with better incentives to reduce their costs than does cost-of-service regulation.

PCBs (Polychlorinated Biphenyls): A group of organic compounds used in the manufacture of plastics and formerly used as a coolant in electric transformers. In the environment, PCBs are highly toxic to aquatic life. They persist in the environment for long periods of time and are biologically accumulative.

Peak Electricity Demand: The maximum electricity used to meet the cooling load of a building or buildings in a given area.

Peak Levels: Levels of airborne pollutant contaminants much higher than average or occurring for short periods of time in response to sudden releases.

Peak Load: The highest electrical demand within a particular period of time. Daily electric peaks on weekdays occur in late afternoon and early evening. Annual peaks occur on hot summer days.

Peak Load or Peak Demand: The electric load that corresponds to a maximum level of electric demand in a specified time period.

Peak Load Power Plant: A power generating station that is normally used to produce extra electricity during peak load times.

Peaker: A nickname for a power generating station that is normally used to produce extra electricity during peak load times.

Peaking Unit: A power generator used by a utility to produce extra electricity during peak load times.

Peat: A heterogeneous mixture of partly decomposed organic matter that has accumulated in a water saturated environment over a very long period of time. Peat geologically is considered a very young form of coal and has a heating value of 6,600 Btu/pound in situ. California has minor peat resources.

Percent Saturation: The amount of a substance that is dissolved in a solution compared to the amount that could be dissolved in it.

Perched Water: Zone of unpressurized water held above the water table by impermeable rock or sediment.

Percolating Water: Water that passes through rocks or soil under the force of gravity.

Percolation: 1. The movement of water downward and radially through subsurface soil layers, usually continuing downward to ground water. Can also involve the upward movement of water. 2. Slow seepage of water through a filter.

Performance Bond:
Cash or securities deposited before a landfill operating permit is issued, which are held to ensure that all requirements for operating ad subsequently closing the landfill are faithful performed. The money is returned to the owner after the proper closure of the landfill is completed. If contamination or other problems appear at any time during operation, or upon closure, and are not addressed, the owner must forfeit all or part of the bond which is then used to cover clean-up costs.

Performance Standards:
1. Regulatory requirements limiting the concentrations of designated organic compounds, particulate matter, and hydrogen chloride in emissions from incinerators. 2. Operating standards established by EPA for various permitted pollution control systems, asbestos inspections, and various program operations and maintenance requirements.

Periphyton: Microscopic underwater plants and animals that are firmly attached to solid surfaces such as rocks, logs, and pilings.

Perm: The measurement of water vapor through different materials measured in perm-inch (mass of water vapor moving through a unit area in unit time).

Permeability: The rate at which liquids pass through soil or other materials in a specified direction.

Permit: An authorization, license, or equivalent control document issued by EPA or an approved state agency to implement the requirements of an environmental regulation; e.g. a permit to operate a wastewater treatment plant or to operate a facility that may generate harmful emissions.

Persistence: Refers to the length of time a compound stays in the environment, once introduced. A compound may persist for less than a second or indefinitely.

Persistent Pesticides: Pesticides that do not break down chemically or break down very slowly and remain in the environment after a growing season.

Pest: An insect, rodent, nematode, fungus, weed or another form of terrestrial or aquatic plant or animal life that is injurious to health or the environment.

Pest Control Operator: Person or company that applies pesticides as a business (e.g. exterminator); usually describes household services, not agricultural applications.

Pesticide: Substances or mixture there of intended for preventing, destroying, repelling, or mitigating any pest. Also, any substance or mixture intended for use as a plant regulator, defoliant, or desiccant.

Pesticide Tolerance:
The amount of pesticide residue allowed by law to remain in or on a harvested crop. EPA sets these levels well below the point where the compounds might be harmful to consumers.

Chemicals made from oil.

Petrodollars: Money paid to other countries for oil imported to the United States.

Petroleum: Oil as finding it its natural state under the ground.

Petroleum: Crude oil or any fraction thereof that is liquid under normal conditions of temperature and pressure. The term includes petroleum-based substances comprising a complex blend of hydrocarbons derived from crude oil through the process of separation, conversion, upgrading, and finishing, such as motor fuel, jet oil, lubricants, petroleum solvents, and used oil.

Petroleum Derivatives:
Chemicals formed when gasoline breaks down in contact with ground water.

pH: An expression of the intensity of the basic or acid condition of a liquid; may range from 0 to 14, where 0 is the most acid and 7 is neutral. Natural waters usually have a pH between 6.5 and 8.5.

Pharmacokinetics: The study of the way that drugs move through the body after they are swallowed or injected.

Phenolphthalein Alkalinity: The alkalinity in a water sample measured by the amount of standard acid needed to lower the pH to a level of 8.3 as indicated by the change of color of the phenolphthalein from pink to clear.

Organic compounds that are by-products of petroleum refining, tanning, and textile, dye, and resin manufacturing. Low concentrations cause taste and odor problems in water; higher concentrations can kill aquatic life and humans.

Phosphates: Certain chemical compounds containing phosphorus.

Phosphogypsum Piles (Stacks): Principal by-product generated in the production of phosphoric acid from phosphate rock. These piles may generate radioactive radon gas.

An essential chemical food element that can contribute to the eutrophication of lakes and other water bodies. Increased phosphorus levels result from discharge of phosphorus-containing materials into surface waters.

Phosphorus Plants: Facilities using electric furnaces to produce elemental phosphorous for commercial use, such as high-grade phosphoric acid, phosphate-based detergent, and organic chemicals use.

Photocell: A device that produces an electric reaction to visible radiant energy (light).

Photochemical Oxidants:
Air pollutants formed by the action of sunlight on oxides of nitrogen and hydrocarbons.

Photochemical Smog:
Air pollution caused by chemical reactions of various pollutants emitted from different sources.

The manufacture by plants of carbohydrates and oxygen from carbon dioxide mediated by chlorophyll in the presence of sunlight.

A process by which green plants change carbon dioxide into oxygen and organic materials. The energy for this process comes from sunlight.

Photovoltaic Cell:
A semiconductor that converts light directly into electricity.

Physical and Chemical Treatment: Processes generally used in large-scale wastewater treatment facilities. Physical processes may include air-stripping or filtration. Chemical treatment includes coagulation, chlorination, or ozonation. The term can also refer to treatment of toxic materials in surface and ground waters, oil spills, and some methods of dealing with hazardous materials on or in the ground.

Phytoplankton: That portion of the plankton community comprised of tiny plants; e.g. algae, diatoms.

Phytoremediation: Low-cost remediation option for sites with widely dispersed contamination at low concentrations.

Harmful to plants.

Phytotreatment: The cultivation of specialized plants that absorb specific contaminants from the soil through their roots or foliage. This reduces the concentration of contaminants in the soil but incorporates them into biomass that may be released back into the environment when the plant dies or is harvested.

Piezometer: A non-pumping well, generally of small diameter, for measuring the elevation of a water table.

Pilot Tests:
Testing a cleanup technology under actual site conditions to identify potential problems prior to full-scale implementation.

Pipeline: A line of pipe with pumping machinery and apparatus (including valves, compressor units, metering stations, regulator stations, etc.) for conveying a liquid or gas.

Plankton: Tiny plants and animals that live in water.

Plasma Arc Reactors: devices that use an electric arc to thermally decompose organic and inorganic materials at ultra-high temperatures into gasses and a vitrified slag residue. A plasma arc reactor can operate as any of the following:

• integral component of chemical, fuel, or electricity production systems, processing high or medium value organic compounds into a synthetic gas used as a fuel

• materials recovery device, processing scrap to recover metal from the slag

• destruction or incineration system, processing waste materials into slag and gasses ignited inside of a secondary combustion chamber that follows the reactor

Plasmid: A circular piece of DNA that exists apart from the chromosome and replicates independently of it. Bacterial plasmids carry information that renders the bacteria resistant to antibiotics. Plasmids are often used in genetic engineering to carry desired genes into organisms.

Any various organic compounds produced by polymerization, capable of being molded, extruded, cast into various shapes and films or drawn into filaments used as textile fibers.

Plastics: Non-metallic chemoreactive compounds molded into rigid or pliable construction materials, fabrics, etc.

Plate Tower Scrubber:
An air pollution control device that neutralizes hydrogen chloride gas by bubbling alkaline water through holes in a series of metal plates.

Plug Flow: Type of flow that occurs in tanks, basins, or reactors when a slug of water moves through without ever dispersing or mixing with the rest of the water flowing through.

Act or process of stopping the flow of water, oil, or gas into or out of a formation through a borehole or well penetrating that formation.

Plume: 1. A visible or measurable discharge of a contaminant from a given point of origin. It can be visible or thermal in water, or visible in the air as, for example, a plume of smoke. 2 The area of radiation leaking from a damaged reactor. 3. Area downwind within which a release could be dangerous for those exposed to leaking fumes.

Plutonium: A radioactive metallic element chemically similar to uranium.

Point Source: A stationary location or fixed facility from which pollutants are discharged; any single identifiable source of pollution; e.g. a pipe, ditch, ship, ore pit, factory smokestack.

Point Source Pollution: Pollution that originates from specific, known sources such as municipal and industrial facilities, by passes and overflows from municipal sewage systems, non-permitted and illegal dischargers and water that is generated through oil and gas operations.

Point-of-Contact Measurement of Exposure: Estimating exposure by measuring concentrations over time (while the exposure is taking place) at or near the place where it is occurring.

Point-of-Disinfectant Application: The point where disinfectant is applied and water downstream of that point is not subject to recontamination by surface water runoff.

Point-of-Use Treatment Device: Treatment device applied to a single tap to reduce contaminants in the drinking water at the one faucet.

Pollen: The fertilizing element of flowering plants; background air pollutant.

Pollutant: Generally, any substance introduced into the environment that adversely affects the usefulness of a resource or the health of humans, animals, or ecosystems.

Pollutant Pathways: Avenues for distribution of pollutants. In most buildings, for example, HVAC systems are the primary pathways although all building components can interact to affect how air movement distributes pollutants.

Pollution: Generally, the presence of a substance in the environment that because of its chemical composition or quantity prevents the functioning of natural processes and produces undesirable environmental and health effects. Under the Clean Water Act, for example, the term has been defined as the man-made or man-induced alteration of the physical, biological, chemical, and radiological integrity of water and other media.

Pollution Prevention: 1. Identifying areas, processes, and activities which create excessive waste products or pollutants in order to reduce or prevent them through, alteration, or eliminating a process. Such activities, consistent with the Pollution Prevention Act of 1990, are conducted across all EPA programs and can involve cooperative efforts with such agencies as the Departments of Agriculture and Energy. 2. EPA has initiated a number of voluntary programs in which industrial, or commercial or "partners" join with EPA in promoting activities that conserve energy, conserve and protect the water supply, reduce emissions or find ways of utilizing them as energy resources, and reduce the waste stream. Among these are Agstar, to reduce methane emissions through manure management; Climate Wise, to lower industrial greenhouse-gas emissions and energy costs. Coal bed Methane Outreach, to boost methane recovery at coal mines. Design for the Environment, to foster including environmental considerations in product design and processes. Energy Star programs, to promote energy efficiency in commercial and residential buildings, office equipment, transformers, computers, office equipment, and home appliances. Environmental Accounting, to help businesses identify environmental costs and factor them into management decision making. Green Chemistry, to promote and recognize cost-effective breakthroughs in chemistry that prevent pollution. Green Lights, to spread the use of energy-efficient lighting technologies. Indoor Environments, to reduce risks from indoor-air pollution. Landfill Methane Outreach, to develop landfill gas-to-energy projects. Natural Gas Star, to reduce methane emissions from the natural gas industry. Ruminant Livestock Methane, to reduce methane emissions from ruminant livestock. Transportation Partners, to reduce carbon dioxide emissions from the transportation sector. Voluntary Aluminum Industrial Partnership, to reduce perfluorocarbon emissions from the primary aluminum industry. WAVE, to promote efficient water use in the lodging industry. Waste-wise, to reduce business-generated solid waste through prevention, reuse, and recycling.

Polonium: A radioactive element that occurs in pitchblende and other uranium-containing ores.

Polychlorinated Biphenyls:
A group of toxic, persistent chemicals used in electrical transformers and capacitors for insulating purposes, and in gas pipeline systems as a lubricant. The sale and new use of these chemicals, also known as PCBs, were banned by law in 1979.

Polyelectrolytes: Synthetic chemicals that help solids to clump during sewage treatment.

Polyethylene Terephthalate (PETE):
Thermoplastic material used in plastic soft drink and rigid containers. A thermoplastic material that is clear, tough and has good gas and moisture barrier properties.

Polylactic Acid (PLA): A biodegradable thermoplastic derived from the lactic acid in corn; resembles clear polystyrene. PLA can be used in a number of industrial products including textiles.

Polymer: A natural or synthetic chemical structure where two or more like molecules are joined to form a more complex molecular structure (e.g. polyethylene in plastic).

Polyvinyl Chloride (PVC): A tough, environmentally indestructible plastic that releases hydrochloric acid when burned. Synthetic thermoplastic polymer made from vinyl chloride.

Poolco: Poolco refers to a specialized, centrally dispatched spot market power pool that functions as a short-term market. It establishes the short-term market clearing price and provides a system of long-term transmission compensation contracts. It is regulated to provide open access, comparable service, and cost recovery. A poolco would make ancillary generation services, including load following, spinning reserve, backup power, and reactive power, available to all market participants on comparable terms. In addition, the Poolco provides settlement mechanisms when differences in contracted volumes exist between buyers and sellers of energy and capacity.

A group of interbreeding organisms occupying a particular space; the number of humans or other living creatures in a designated area.

Population at Risk: A population subgroup that is more likely to be exposed to a chemical, or is more sensitive to the chemical, than is the general population.

Porosity: Degree to which soil, gravel, sediment, or rock is permeated with pores or cavities through which water or air can move.

Portal-of-Entry Effect:
A local effect produced in the tissue or organ of the first contact between a toxicant and the biological system.

Portfolio Management:
The functions of resource planning and procurement under a traditional utility structure. Portfolio management can also be defined as the aggregation and management of a diverse portfolio of supply (and demand-reduction) resources which will act as a hedge against various risks that may affect specific resources (i.e., fuel price fluctuations and certainty of supply, common mode failures, operational reliability, changes in environmental regulations, and the risk of health, safety, and environmental damages that may occur as a result of operating some supply resources). Under a more market-driven power sector with a "power-pool" or POOLCO wholesale market structure, a portfolio manager would: aggregate and manage a diverse portfolio of spot-market purchases, contracts-for-differences, futures contracts and other market-hedging-type contracts and mechanisms.

Post-Chlorination: Addition of chlorine to plant effluent for disinfectant purposes after the effluent has been treated.

Post-Closure: The time period following the shutdown of a waste management or manufacturing facility; for monitoring purposes, often considered to be 30 years.

Post-Closure: The period of time after a landfill is certified as closed by a state regulatory agency until WMI has no further monitoring responsibility. Environmental and other regulations require the owner of the closed landfill to continue monitoring activities and general maintenance of the site for a specific period of time (generally 30 years).

Post-Consumer Materials/Waste: Materials or finished products that have served their intended use and have been diverted or recovered from waste destined for disposal, having completed their lives as consumer items. Postconsumer materials are part of the broader category of recovered materials.

Post-Consumer Recycled Content:
Material that has been recovered after its intended use as a consumer product. Examples include reclaimed carpet tiles (for new tile backing).

Post-Consumer Recycling:
Use of materials generated from residential and consumer waste for new or similar purposes; e.g. converting wastepaper from offices into corrugated boxes or newsprint.

Potable Water:
Water that is safe for drinking and cooking.

The ability of one chemical to increase the effect of another chemical.

Potentiometric Surface: The surface to which water in an aquifer can rise by hydrostatic pressure.

Power: Electricity for use as energy.

Power Authorities:
Quasi-governmental agencies that perform all or some of the functions of a public utility.

Power Plant:
A central station generating facility that produces energy.

Power Pool:
An entity established to coordinate short-term operations to maintain system stability and achieve least-cost dispatch. The dispatch provides backup supplies, short-term excess sales, reactive power support, and spinning reserve. Historically, some of these services were provided on an unpriced basis as part of the members' utility franchise obligations. Coordinating short-term operations includes the aggregation and firming of power from various generators, arranging exchanges between generators, and establishing (or enforcing) the rules of conduct for wholesale transactions. The pool may own, manage and/or operate the transmission lines ("wires") or be an independent entity that manages the transactions between entities. Often, the power pool is not meant to provide transmission access and pricing, or settlement mechanisms if differences between contracted volumes among buyers and sellers exist.

Power Pool: Two or more interconnected utilities that plan and operate to supply electricity in the most reliable, economical way to meet their combined load.

Power Purchase Agreement (PPA):
A contract entered into by an independent power producer and an electric utility. The power purchase agreement specifies the terms and conditions under which electric power will be generated and purchased. Power purchase agreements require the independent power producer to supply power at a specified price for the life of the agreement.

PPM (Parts Per Million): The unit commonly used to represent the degree of pollutant concentration where the concentrations are small.

Pre-Consumer Materials/Materials Waste: Generated in manufacturing and converting processes such as manufacturing scrap and trimmings and cuttings. Includes print overruns, overissue publications, and obsolete inventories.

Pre-Consumer Recycled Content: Material that has been recovered from the manufacturing waste stream before it has served its intended purpose.

Preferred Day-Ahead Schedule: A Scheduling Coordinator's preferred schedule for the ISO day-ahead scheduling process.

Preferred Hour-Ahead Schedule: A Scheduling Coordinator's preferred schedule for the ISO hour-ahead scheduling process.

Preferred Schedule: The initial schedule produced by a Scheduling Coordinator that represents its preferred mix of generation to meet demand. The schedule includes the quantity of output (generators) and consumption (loads), details of any adjustment bids, and the location of each generator and load. The schedule also specifies the quantities and location of trades between the Scheduling Coordinator and all other Scheduling Coordinators and is balanced with respect to generation, transmission losses, load, and trades.

Pre-Harvest Interval: The time between the last pesticide application and harvest of the treated crops.

Prechlorination: The addition of chlorine at the headworks of a treatment plant prior to other treatment processes. Done mainly for disinfection and control of tastes, odors, and aquatic growths, and to aid in coagulation and settling,

Precipitate: A substance separated from a solution or suspension by the chemical or physical change.

Precipitation: Removal of hazardous solids from liquid waste to permit safe disposal; removal of particles from airborne emissions as in rain (e.g. acid precipitation).

Precipitator: Pollution control device that collects particles from an air stream.

Precursor: In photochemistry, a compound antecedent to a pollutant. For example, volatile organic compounds (VOCs) and nitric oxides of nitrogen react in sunlight to form ozone or other photochemical oxidants. As such, VOCs and oxides of nitrogen are precursors.

Preliminary Assessment: The process of collecting and reviewing available information about a known or suspected waste site or release.

Prescriptive: Water rights which are acquired by diverting water and putting it to use in accordance with specified procedures; e.g. filing a request with a state agency to use unused water in a stream, river, or lake.

Pressed Wood Products:
Materials used in building and furniture construction that are made from wood veneers, particles, or fibers bonded together with an adhesive under heat and pressure.

Pressure Sewers:
A system of pipes in which water, wastewater, or other liquid is pumped to a higher elevation.

Pressure, Static:
In flowing air, the total pressure minus velocity pressure, pushing equally in all directions.

Pressure, Total: In flowing air, the sum of the static and velocity pressures.

Pressure, Velocity:
In flowing air, the pressure due to velocity and density of air.

Pressurized Water Reactor (PWR): A nuclear power unit cooled by water that is pressurized to keep it from boiling when it reaches high temperatures.

Pretreatment: Processes used to reduce, eliminate, or alter the nature of wastewater pollutants from non-domestic sources before they are discharged into publicly owned treatment works (POTWs).

Prevalent Level Samples: Air samples taken under normal conditions (also known as ambient background samples).

Prevalent Levels: Levels of airborne contaminant occurring under normal conditions.

Primary Effect: An effect where the stressor acts directly on the ecological component of interest, not on other parts of the ecosystem.

Primary Fuel: Fuel consumed in the original production of energy, before the conversion takes place.

Primary Material:
A commercial material produced from virgin materials used for manufacturing basic products. Examples include wood pulp, iron ore, and silica sand.

Primary Treatment:
First stage of wastewater treatment in which solids are removed by screening and settling.

Primary Waste Treatment: First steps in wastewater treatment; screens and sedimentation tanks are used to remove most materials that float or will settle. Primary treatment removes about 30 percent of carbonaceous biochemical oxygen demand from domestic sewage.

Principal Organic Hazardous Constituents (POHCs):
Hazardous compounds monitored during an incinerator's trial burn, selected for high concentration in the waste feed and difficulty of combustion.

Prions: Microscopic particles made of protein that can cause disease.

Prior Appropriation:
A doctrine of water law that allocates the rights to use water on a first-come, first-served basis.

Probability of Detection: The likelihood, expressed as a percentage, that a test method will correctly identify a leaking tank.

Process Variable: A physical or chemical quantity which is usually measured and controlled in the operation of a water treatment plant or industrial plant.

Process Verification:
Verifying that process raw materials, water usage, waste treatment processes, production rate and other facts relative to quantity and quality of pollutants contained in discharges are substantially described in the permit application and the issued permit.

Process Wastewater:
Any water that comes into contact with any raw material, product, by-product, or waste.

Process Weight: Total weight of all materials, including fuel, used in a manufacturing process; used to calculate the allowable particulate emission rate.

Processing: Preparing MSW materials for subsequent use or management, using processes such as baling, magnetic separation, crushing, and shredding. The term is also sometimes used to mean separation of recyclables from mixed MSW.

Producer Responsibility: A system in which a producer of products or services takes responsibility for the waste that results from the products or services marketed, by reducing materials used in production, making repairable or recyclable goods, and/ or reducing packaging.

Plants that perform photosynthesis and provide food to consumers.

Product Level:
The level of a product in a storage tank.

Product Stewardship: The responsible and ethical management of the health, safety and environmental aspects of a product throughout its life cycle.

Product Water: Water that has passed through a water treatment plant and is ready to be delivered to consumers.

Products of Incomplete Combustion (PICs):
Organic compounds formed by combustion. Usually generated in small amounts and sometimes toxic, PICs are heat-altered versions of the original material fed into the incinerator (e.g. charcoal is a P.I.C. from burning wood).

Programmable Controller: A device that controls the operation of electrical equipment (such as air conditioning units and lights) according to a preset time schedule.

Propane: A gas that is both presents in natural gas and refined from crude oil. It is used for heating, lighting and industrial applications.

Propellant: Liquid in a self-pressurized pesticide product that expels the active ingredient from its container.

Proportionate Mortality Ratio (PMR):
The number of deaths from a specific cause in a specific period of time per 100 deaths from all causes in the same time period.

Proteins: Complex nitrogenous organic compounds of high molecular weight made of amino acids; essential for growth and repair of animal tissue. Many, but not all, proteins are enzymes.

Protocol: A series of formal steps for conducting a test.

Protoplast: A membrane-bound cell from which the outer wall has been partially or completely removed. The term often is applied to plant cells.

Protozoa: One-celled animals that are larger and more complex than bacteria. It may cause disease.

Provider Of Last Resort: A legal obligation(traditionally given to utilities) to provide service to a customer where competitors have decided they do not want that customer's business.

Public Adviser:
An appointee of the governor who attends all meetings of the Energy Commission and provides assistance to members of the public and interveners in cases before the Commission.

Public Interest Goals: Public interest goals of electric utility regulation include: 1) inter-and intra-class and intergenerational equity); 2) the equal treatment of equals (horizontal equity); 3) balancing long- and short-term goals that have the potential to affect intergenerational balance; 4) protecting against the abuse of monopoly power; and 5) general protection of the health and welfare of the citizens of the state, nation, and the world. Environmental and other types of social costs are subsumed under the equity and health and welfare responsibilities.

PUHCA: The Public Utility Holding Company Act of 1935. This act prohibits acquisition of any wholesale or retail electric business through a holding company unless that business forms part of an integrated public utility system when combined with the utility's other electric business. The legislation also restricts ownership of an electric business by non-utility corporations.

Pumped Hydroelectric Storage:
 The commercial method used for large-scale storage of power. During off-peak times, excess power is used to pump water to a reservoir. During peak times, the reservoir releases water to operate hydroelectric generators.

Pumping Station:
 The mechanical device installed in sewer or water system or other liquid-carrying pipelines to move the liquids to a higher level.

Pumping Test:
A test conducted to determine aquifer or well characteristics.

Purging: Removing stagnant air or water from sampling zone or equipment prior to sample collection.

PURPA: The Public Utility Regulatory Policy Act of 1978. Among other things, this federal legislation requires utilities to buy electric power from private "qualifying facilities," at an avoided cost rate. This avoided cost rate is equivalent to what it would have otherwise cost the utility to generate or purchase that power themselves. Utilities must further provide customers who choose to self-generate a reasonably priced back-up supply of electricity.

PURPA: The Public Utilities Regulatory Policies Act of 1978 (PURPA) is implemented by the Federal Energy Regulatory Commission and the California Public Utilities Commission (CPUC). Under PURPA each electric utility is required to offer to purchase available electric energy from cogeneration and small power production facilities.

Biological decomposition of organic matter; associated with anaerobic conditions.

Subject to decomposition or decay. Usually used in reference to food wastes and other organic wastes that decay quickly.

Putrescible: Able to rot quickly enough to cause odors and attract flies.

Decomposition of a chemical by extreme heat.

Pyrolysis: Chemical decomposition of a substance by heat in the absence of oxygen, resulting in various hydrocarbon gasses and carbon-like residue.

PX Load:
Load that has been scheduled by the PX, and which is received through the use of transmission or distribution facilities owned by participating transmission owners.

PX Participant: An entity that is authorized to buy or sell energy or ancillary services through the PX, and any agent authorized to act on behalf of such an entity.

Quad: One quadrillion (1015 or 1,000,000,000,000,000) British thermal units (Btus); an amount of energy equal to 170 million barrels of oil. Total U.S. consumption of all forms of energy is (in the 1990s) about 83 quads in an average year.

Qualifying Facility:
A cogenerator or small power producer which under federal law, has the right to sell its excess power output to the public utility.

Qualifying Facility: QFs are non-utility power producers that often generate electricity using renewable and alternative resources, such as hydro, wind, solar, geothermal or biomass (solid waste). QFs must meet certain operating, efficiency, and fuel-use standards set forth by the Federal Energy Regulatory Commission (FERC). If they meet these FERC standards, utilities must buy power from them. QFs usually have long-term contracts with utilities for the purchase of this power, which is among the utility's highest-priced resources.

Qualifying Facility (Qf):
Under PURPA, QFs were allowed to sell their electric output to the local utility at avoided cost rates. To become a QF, the independent power supplier had to produce electricity with a specified fuel type (cogeneration or renewables), and meet certain ownership, size, and efficiency criteria established by the Federal Energy Regulatory Commission.

Quality Assurance/Quality Control: A system of procedures, checks, audits, and corrective actions to ensure that all EPA research design and performance, environmental monitoring and sampling, and other technical and reporting activities are of the highest achievable quality.

Quench Tank:
A water-filled tank used to cool incinerator residues or hot materials during industrial processes.

R-Value: A unit of thermal resistance used for comparing insulating values of different material. It is basically a measure of the effectiveness of insulation in stopping heat flow. The higher the R-value number, a material, the greater its insulating properties and the slower the heat flow through it. The specific value needed to insulate a home depends on climate, type of heating system and other factors.

Rad: A unit of measure of absorbed radiation. Acronym for radiation absorbed dose. One rad equals 100 ergs of radiation energy per gram of absorbing a material.

Radiant Barrier: A device designed to reduce or stop the flow of radiant energy.

Radiant Energy:
Energy transferred by the exchange of electromagnetic waves from a hot or warm object to one that is cold or cooler. Direct contact with the object is not necessary for the heat transfer to occur.

Radiation: The flow of energy across open space via electromagnetic waves such as light; passage of heat from one object to another without warming the air space in between.

Radiation: Transmission of energy though space or any medium. It is also known as radiant energy.

Radiation Standards: Regulations that set maximum exposure limits for protection of the public from radioactive materials.

Radioactive Decay:
Spontaneous change in an atom by emission of charged particles and/or gamma rays; also known as radioactive disintegration and radioactivity.

Radioactive Substances: Substances that emit ionizing radiation.

Radioactive Waste: Any waste that emits energy as rays, waves, streams or energetic particles. Radioactive materials are often mixed with hazardous waste, from nuclear reactors, research institutions, or hospitals.

Radioisotopes: Chemical variants of radioactive elements with potentially oncogenic, teratogenic, and mutagenic effects on the human body.

Radionuclide: Radioactive particle, man-made (anthropogenic) or natural, with a distinct atomic weight number. It can have a long life as soil or water pollutant.

Radius of Vulnerability Zone:
The maximum distance from the point of release of a hazardous substance in which the airborne concentration could reach the level of concern under specified weather conditions.

Radius of Influence:
1. The radial distance from the center of a wellbore to the point where there is no lowering of the water table or potentiometric surface (the edge of the cone of depression); 2. the radial distance from an extraction well that has adequate air flow for effective removal of contaminants when a vacuum is applied to the extraction well.

Radon: A colorless naturally occurring, radioactive, inert gas formed by radioactive decay of radium atoms in soil or rocks.

Radon Daughters/Radon Progeny:
Short-lived radioactive decay products of radon that decay into longer-lived lead isotopes that can attach themselves to airborne dust and other particles and, if inhaled, damage the linings of the lungs.

Radon Decay Products: A term used to refer collectively to the immediate products of the radon decay chain. These include Po-218, Pb-214, Bi-214, and Po-214, which have an average combined half-life of about 30 minutes.

Rankine Cycle: The steam-Rankine cycle employing steam turbines has been the mainstay of utility thermal electric power generation for many years. The cycle, as developed over the years uses superheat, reheat and regeneration. Modern steam Rankine systems operate at a cycle top temperature of about 1,073 degrees Celsius with efficiencies of about 40 percent.

Rasp: A machine that grinds waste into a manageable material and helps prevent odor.

Rate-Basing: Refers to practice by utilities of allotting funds invested in utility Research Development Demonstration and Commercialization and other programs from rate-payers, as opposed to allocating these costs to shareholders.

Raw Agricultural Commodity:
An unprocessed human food or animal feed crop (e.g., raw carrots, apples, corn, or eggs.)

Raw Fuel Coal: Natural gas, wood or other fuel that is used in the form in which it is found in nature, without chemical processing.

Raw Sewage: Untreated wastewater and its contents.

Raw Water: Intake water prior to any treatment or use.

RDF (Refuse Derived Fuel): The fuel component of municipal solid waste (MSW), which is the by-product of shredding MSW to a uniform size, screening out oversized materials and isolating ferrous material in magnetic separation. The resulting RDF can be burned as a fuel source.

Reactor: A device in which a controlled nuclear chain reaction can be maintained, producing heat energy.

Real-Time Market:
The competitive generation market controlled and coordinated by the ISO for arranging real-time imbalance energy.

Real-Time Pricing:
The instantaneous pricing of electricity based on the cost of the electricity available for use at the time the electricity is demanded by the customer.

Re-entry: (In indoor air program) Refers to air exhausted from a building that is immediately brought back into the system through the air intake and other openings.

Reactivity: Refers to those hazardous wastes that are normally unstable and readily undergo violent chemical change but do not explode.

Reaeration: Introduction of air into the lower layers of a reservoir. As the air bubbles form and rise through the water, the oxygen dissolves into the water and replenishes the dissolved oxygen. The rising bubbles also cause the lower waters to rise to the surface where they take on oxygen from the atmosphere.

Real-Time Monitoring:
Monitoring and measuring environmental developments with technology and communications systems that provide time-relevant information to the public in an easily understood format people can use in day-to-day decision-making about their health and the environment.

Recarbonization: Process in which carbon dioxide is bubbled into water being treated to lower the pH.

Receiving Waters:
A river, lake, ocean, stream or other watercourses into which wastewater or treated effluent is discharged.

Ecological entity exposed to a stressor.

Recharge: The process by which water is added to a zone of saturation, usually by percolation from the soil surface; e.g., the recharge of an aquifer.

Recharge Area:
A land area in which water reaches the zone of saturation from surface infiltration, e.g., where rainwater soaks through the earth to reach an aquifer.

Recharge Rate:
The quantity of water per unit of time that replenishes or refills an aquifer.

Reclaimed Oil: Lubricating oil that is processed to be used over again.

Reclaimed Polymer: Synthetic waste from any source that is melted down and re-extruded.

Reclamation: (In recycling) Restoration of materials found in the waste stream to a beneficial use which may be for purposes other than the original use.

Recombinant Bacteria: A microorganism whose genetic makeup has been altered by the deliberate introduction of new genetic elements. The offspring of these altered bacteria also contain these new genetic elements; i.e. they "breed true."

Recombinant DNA:
The new DNA that is formed by combining pieces of DNA from different organisms or cells.

Recommended Maximum Contaminant Level (RMCL): The maximum level of a contaminant in drinking water at which no known or anticipated the adverse effect on human health would occur, and that includes an adequate margin of safety. Recommended levels are non-enforceable health goals.

Reconstructed Source: Facility in which components are replaced to such an extent that the fixed capital cost of the new components exceeds 50 percent of the capital cost of constructing a comparable brand-new facility. New-source performance standards may be applied to sources reconstructed after the proposal of the standard if it is technologically and economically feasible to meet the standards.

Reconstruction of Dose:
Estimating exposure after it has occurred by using evidence within an organism such as chemical levels in tissue or fluids.

Recool: The sensible cooling of air that has been previously heated by HVAC systems serving the same building.

Record of Decision (ROD): A public document that explains which cleanup alternative(s) will be used at National Priorities List sites where, under CERCLA, Trust Funds pay for the cleanup.

Recovered Energy:
Reused heat or energy that otherwise would be lost. For example, a combined cycle power plant recaptures some of its own waste heat and reuses it to make extra electric power.

Recovery Efficiency (Thermal efficiency):
In a water heater, a measure of the percentage of heat from the combustion of gas which is transferred to the water as measured under specified test conditions.

Recovery Rate: Percentage of usable recycled materials that have been removed from the total amount of municipal solid waste generated in a specific area or by a specific business.

Recyclables: Items that can be reprocessed into feedstock for new products. Common examples are paper, glass, aluminum, corrugated cardboard and plastic containers.

Recycle/Reuse: Minimizing waste generation by recovering and reprocessing usable products that might otherwise become waste (.i.e. recycling of aluminum cans, paper, and bottles, etc.).

Recycled Content: Refers to the percentage of the total weight of recycled materials in a product.

The series of activities, including collection, separation, and processing, by which materials are recovered from the waste stream for use as raw materials in the manufacture of new products.

Recycling: The process of transforming materials into raw materials for manufacturing new products, which may or may not be similar to the original product.

Recycling and Reuse Business Assistance Centers: Located in state solid-waste or economic-development agencies, these centers provide recycling businesses with customized and targeted assistance.

Recycling (Closed Loop Recycling): The process of recycling in such a way that the components of the original product are reclaimed or utilized into similar products without the process of down cycling.

Recycling Economic Development Advocates:
Individuals hired by state or tribal economic development offices to focus financial, marketing, and permitting resources on creating recycling businesses.

Recycling Mill: Facility where recovered materials are remanufactured into new products.

Recycling Technical Assistance Partnership National Network:
A national information-sharing resource designed to help businesses and manufacturers increase their use of recovered materials.

Red Border: An EPA document undergoing review before being submitted for final management decision-making.

Red Tide: A proliferation of marine plankton toxic and often fatal to fish, perhaps stimulated by the addition of nutrients. A tide can be red, green, or brown, depending on the coloration of the plankton.

Redemption Program:
Program in which consumers are monetarily compensated for the collection of recyclable materials, generally through prepaid deposits or taxes on beverage containers. In some states or localities legislation has enacted redemption programs to help prevent roadside litter.

Reduction: The addition of hydrogen, removal of oxygen, or addition of electrons to an element or compound.

Reentry Interval: The period of time immediately following the application of a pesticide during which unprotected workers should not enter a field.

Reference Dose (RfD): The RfD is a numerical estimate of a daily oral exposure to the human population, including sensitive subgroups such as children, that is not likely to cause harmful effects during a lifetime. RfDs are generally used for health effects that are thought to have a threshold or low dose limit for producing effects.

Refiner: Is any person who owns, operates, or controls the operations of one or more refineries.

Refinery: A facility that separates crude oil into varied oil products. The refinery uses progressive temperature changes to separate by vaporizing the chemical components of crude oil that have different boiling points. These are distilled into usable products such as gasoline, fuel oil, lubricants, and kerosene.

Reformulated Gasoline: Gasoline with a different composition from conventional gasoline (e.g., lower aromatics content) that cuts air pollutants.

Reformulated Gasoline (RFG): A cleaner-burning gasoline that has had its compositions and/or characteristics altered to reduce vehicular emissions of pollutants.

Refrigerant: A fluid such as Freon that is used in cooling devices to absorb heat from surrounding air or liquids as it evaporates.

Refueling Emissions: Emissions released during vehicle re-fuelling.

Refuse: A term often used interchangeably with solid waste.

Refuse-Derived Fuel (RDF):
Fuel produced from MSW that has undergone processing. Processing can include separation of recyclables and non-combustible materials, shredding, size reduction, and pelletizing.

Refuse Reclamation:
Conversion of solid waste into useful products; e.g., composting organic wastes to make soil conditioners or separating aluminum and other metals for recycling.

Regeneration: Manipulation of cells to cause them to develop into whole plants.

Regional Response Team (RRT):
Representatives of federal, local, and state agencies who may assist in the coordination of activities at the request of the On-Scene Coordinator before and during a significant pollution incident such as an oil spill, major chemical release, or Superfund response.

Registrant: Any manufacturer or formulator who obtains registration for a pesticide active ingredient or product.

Registration: Formal listing with EPA of a new pesticide before it can be sold or distributed. Under the Federal Insecticide, Fungicide, and Rodenticide Act, EPA is responsible for registration (pre-market licensing) of pesticides on the basis of data demonstrating no unreasonable adverse effects on human health or the environment when applied according to approved label directions.

Registration Standards:
Published documents which include summary reviews of the data available on a pesticide's active ingredient, data gaps, and the Agency's existing regulatory position on the pesticide.

Regulated Asbestos-Containing Material (RACM):
Friable asbestos material or non-friable ACM that will be or has been subjected to sanding, grinding, cutting, or abrading or has crumbled, or been pulverized or reduced to powder in the course of demolition or renovation operations.

Regulated Medical Waste: Under the Medical Waste Tracking Act of 1988, any solid waste generated in the diagnosis, treatment, or immunization of human beings or animals, in research pertaining thereto, or in the production or testing of biologicals. Included are cultures and stocks of infectious agents; human blood and blood products; human pathological body wastes from surgery and autopsy; contaminated animal carcasses from medical research; waste from patients with communicable diseases; and all used sharp implements, such as needles and scalpels, and certain unused sharps.

Regulation: The service provided by generating units equipped and operating with automatic generation controls that enables the units to respond to the ISO's direct digital control signals to match real-time demand and resources, consistent with established operating criteria.

Regulatory Must-Run Generation: Utilities will be allowed to generate electricity when hydro resources are spilled for fish releases, irrigation, and agricultural purposes, and to generate power that is required by federal or state laws, regulations, or jurisdictional authorities. Such requirements include hydrological flow requirements, irrigation and water supply, solid-waste generation, or other generation contracts in effect on December 20, 1995.

Regulatory Must-Take Generation: Utilities will be allowed to generate electricity from those resources -- identified by the CPUC -- that are not subject to competition. These resources will be scheduled with the ISO on a must-take basis. Regulatory Must-Take Generation includes QF generating units under federal law, nuclear units and pre-existing power-purchase contracts that have minimum-take provisions.

Reheat: The heating of air that has been previously cooled either by mechanical refrigeration or economizer cooling systems.

Reid Vapour Pressure (RVP): A standard measurement of a liquid's vapor pressure in pounds per square inch at 100 degrees Fahrenheit. It is an indication of the propensity of the liquid to evaporate.

Relative Ecological Sustainability: Ability of an ecosystem to maintain relative ecological integrity indefinitely.

Relative Permeability: The permeability of a rock to gas, NAIL, or water, when any two or more are present.

Relative Risk Assessment: Estimating the risks associated with different stressors or management actions.

Release: Any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment of a hazardous or toxic chemical or extremely hazardous substance.

Reliability: Electric system reliability has two components-- adequacy and security. Adequacy is the ability of the electric system to supply the aggregate electrical demand and energy requirements of the customers at all times, taking into account scheduled and unscheduled outages of system facilities. Security is the ability of the electric system to withstand sudden disturbances such as electric short circuits or unanticipated loss of system facilities.

Reliability Must-Run Generation: The ISO will allow utilities to generate power that is needed to ensure system reliability. This includes generation:

• Required to meet the reliability criteria for interconnected systems operation.

• Needed to meet load (demand) in constrained areas.

• Needed to provide voltage or security support of the ISO or of a local area.

Reliability Must Run Unit: In return for payment, the ISO may call upon the owner of a generating unit to run the unit when required for grid reliability.

Remedial Action (RA): The actual construction or implementation phase of a Superfund site cleanup that follows remedial design.

Remedial Design:
A phase of remedial action that follows the remedial investigation/feasibility study and includes the development of engineering drawings and specifications for a site cleanup.

Remedial Investigation: An in-depth study designed to gather data needed to determine the nature and extent of contamination at a Superfund site; establish site cleanup criteria; identify preliminary alternatives for remedial action; and support technical and cost analyses of alternatives. The remedial investigation is usually done with the feasibility study. Together they are usually referred to as the "RI/FS".

Remedial Project Manager (RPM): The EPA or state official responsible for overseeing on-site remedial action.

Remedial Response: The long-term action that stops or substantially reduces a release or threat of a release of hazardous substances that is serious but not an immediate threat to public health.

Remediation: 1. Cleanup or other methods used to remove or contain a toxic spill or hazardous materials from a Superfund site; 2. for the Asbestos Hazard Emergency Response program, abatement methods including evaluation, repair, enclosure, encapsulation, or removal of greater than 3 linear feet or square feet of asbestos-containing materials from a building.

Remote Sensing: The collection and interpretation of information about an object without physical contact with the object; e.g., satellite imaging, aerial photography, and open path measurements.

Removal Action: Short-term immediate actions are taken to address releases of hazardous substances that require expedited response.

Renewable Energy: Resources that constantly renew themselves or that are regarded as practically inexhaustible. These include solar, wind, geothermal, hydro and wood. Although particular geothermal formations can be depleted, the natural heat in the earth is a virtually inexhaustible reserve of potential energy. Renewable resources also include some experimental or less-developed sources such as tidal power, sea currents, and ocean thermal gradients.

Renewable Energy Production Incentive (REPI): Incentive established by the Energy Policy Act available to renewable energy power projects owned by a state or local government or nonprofit electric cooperative.

Renewable Resources: Renewable energy resources are naturally replenishable but flow-limited. They are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Some (such as geothermal and biomass) may be stock-limited in that stocks are depleted by use, but on a time scale of decades, or perhaps centuries, they can probably be replenished. Renewable energy resources include biomass, hydro, geothermal, solar and the  wind. In the future, they could also include the use of ocean thermal, wave, and tidal action technologies. Utility renewable resource applications include bulk electricity generation, on-site electricity generation, distributed electricity generation, non-grid-connected generation, and demand-reduction (energy efficiency) technologies.

Repeat Compliance Period: Any subsequent compliance period after the initial one.

Reportable Quantity (RQ): Quantity of a hazardous substance that triggers reports under CERCLA. If a substance exceeds its RQ, the release must be reported to the National Response Center, the SERC, and community emergency coordinators for areas likely to be affected.

Repowering: Rebuilding and replacing major components of a power plant instead of building a new one.

Representative Sample: A portion of material or water that is as nearly identical in content and consistency as possible to that in the larger body of material or water being sampled.

Reregistration: The re-evaluation and relicensing of existing pesticides originally registered prior to current scientific and regulatory standards. EPA reregisters pesticides through its Registration Standards Program.

Reregulation: The design and implementation of regulatory practices to be applied to the remaining regulated entities after restructuring of the vertically-integrated electric utility. The remaining regulated entities would be those that continue to exhibit characteristics of a natural monopoly, where imperfections in the market prevent the realization of more competitive results, and where, in light of other policy considerations, competitive results are unsatisfactory in one or more respects. Reregulation could employ the same or different regulatory practices as those used before restructuring.

Research And Development (R&D): Research is the discovery of fundamental new knowledge. Development is the application of new knowledge to develop a potential new service or product. Basic power sector R&D is most commonly funded and conducted through the Department of Energy (DOE), its associated government laboratories, university laboratories, the Electric Power Research Institute (EPRI), and private sector companies.

Reserve: The extra generating capability that an electric utility needs, above and beyond the highest demand level it is required to supply to meet its user's needs.

Reserve Capacity:
Extra treatment capacity built into solid waste and wastewater treatment plants and interceptor sewers to accommodate flow increases due to future population growth.

Reserve Generating Capacity: The amount of power that can be produced at a given point in time by generating units that are kept available in case of special need. This capacity may be used when unusually high power demand occurs, or when other generating units are off-line for maintenance, repair or refueling.

Reserve Margin: The differences between the dependable capacity of a utility's system and the anticipated peak load for a specified period.

Reservoir: Any natural or artificial holding area used to store, regulate, or control water.

Residential Building:
Means any hotel, motel, apartment house, lodging house, single and dwelling, or other residential building which is heated or mechanically cooled.

Residential Use:
Pesticide application in and around houses, office buildings, apartment buildings, motels, and other living or working areas.

Residential Waste: Waste generated in single and multi-family homes, including newspapers, clothing, disposable tableware, food packaging, cans, bottles, food scraps, and yard trimmings other than those that are diverted to backyard composting.

Residual: Amount of a pollutant remaining in the environment after a natural or technological process has taken place; e.g., the sludge remaining after initial wastewater treatment, or particulates remaining in the air after it passes through a scrubbing or other process.

Residual Risk: The extent of health risk from air pollutants remaining after application of the Maximum Achievable Control Technology (MACT).

Residual Saturation: Saturation level below which fluid drainage will not occur.

Residue: The dry solids remaining after the evaporation of a sample of water or sludge.

Residue: Any organic matter left as residue, such as agricultural and forestry residue, including, but not limited to, conifer thinnings, dead and dying trees, commercial hardwood, non-commercial hardwoods and softwoods, chaparral, burn mill, agricultural field, and industrial residues, and manure.

Resistance: For plants and animals, the ability to withstand poor environmental conditions or attacks by chemicals or disease. It may be inborn or acquired.

Resistance (Electrical): The ability of all conductors of electricity to resist the flow of current, turning some of it into heat. Resistance depends on the cross section of the conductor (the smaller the cross section, the greater the resistance) and its temperature (the hotter the cross section, the greater its resistance).

Resistance (Thermal):
The reciprocal of thermal conductance.

Résoplast: The Résoplast unit produces fuel from waste plastic from industrial plants. The properties (homogeneity, calorific value, specific gravity, and composition) of the process's fuels are comparable to those of standard fossil fuels used in certain heavy-energy consuming industrial sectors (cement works, lime plants, paper mills, etc). Résoplast is an alternative to landfilling non-recyclable industrial waste plastic, thereby saving natural hydrocarbon resources.

Resource Conservation and Recovery Act (RCRA):
RCRA is the Resource Conservation and Recovery Act, which was enacted by Congress in 1976. RCRA's primary goals are to protect human health and the environment from the potential hazards of waste disposal, to conserve energy and natural resources, to reduce the amount of waste generated, and to ensure that wastes are managed in an environmentally sound manner.

Resource Efficiency: The use of smaller amounts of physical resources to produce the same product or service. Resource efficiency involves a concern for the use of all physical resources and materials used in the production and use cycle, not just the energy input.

Resource Recovery: The process of obtaining matter or energy from materials formerly discarded.

Response Action: 1. Generic term for actions taken in response to actual or potential health-threatening environmental events such as spills, sudden releases, and asbestos abatement/management problems. 2. A CERCLA-authorized action involving either a short-term removal action or a long-term removal response. This may include but is not limited to: removing hazardous materials from a site to an EPA-approved hazardous waste facility for treatment, containment or treating the waste on-site, identifying and removing the sources of ground-water contamination and halting further migration of contaminants. 3. Any of the following actions taken in school buildings in response to AHERA to reduce the risk of exposure to asbestos: removal, encapsulation, enclosure, repair, and operations and maintenance.

Responsiveness Summary: A summary of oral and/or written public comments received by EPA during a comment period on key EPA documents, and EPA's response to those comments.

Restoration: Measures taken to return a site to pre-violation conditions.

Restricted Entry Interval: The time after a pesticide application during which entry into the treated area is restricted.

Restricted Use: A pesticide may be classified (under FIFRA regulations) for restricted use if it requires special handling because of its toxicity, and, if so, it may be applied only by trained, certified applicators or those under their direct supervision.

Restriction Enzymes:
Enzymes that recognize specific regions of a long DNA molecule and cut it at those points.

Restructuring: The reconfiguration of the vertically-integrated electric utility. Restructuring usually refers to the separation of the various utility functions into individually-operated and -owned entities.

Retail Competition: A system under which more than one electric provider can sell to retail customers, and retail customers are allowed to buy from more than one provider. (See also direct access)

Retail Market: A market in which electricity and other energy services are sold directly to the end-use customer.

The heating of oil shale to get the oil out from it.

Retrofit: Addition of a pollution control device on an existing facility without making major changes to the generating plant. It is also called backfit.

Retrofit: A broad term that applies to any change after the original purchase, such as adding equipment not a part of the original purchase. As applied to alternative fuel vehicles, it refers to conversion devices or kits for conventional fuel vehicles. (Same as aftermarket).

Reusable: Capable of being used again after salvaging or special treatment or processing.

Reuse: Operation whereby a product or component designed and manufactured for a specific purpose is used again for the same or a different purpose. Recycling and reconditioning are special forms of reuse.

Reuse: Using a product or component of municipal solid waste in its original form more than once; e.g., refilling a glass bottle that has been returned or using a coffee can to hold nuts and bolts.

Reverse Osmosis: A treatment process used in water systems by adding pressure to force water through a semi-permeable membrane. Reverse osmosis removes most drinking water contaminants. Also used in wastewater treatment. Large-scale reverse osmosis plants are being developed.

Reversible Effect: An effect which is not permanent; especially adverse effects which diminish when exposure to a toxic chemical stops.

Ribonucleic Acid (RNA): A molecule that carries the genetic message from DNA to a cellular protein-producing mechanism.

Rill: A small channel eroded into the soil by surface runoff; can be easily smoothed out or obliterated by normal tillage.

Ringlemann Chart: A series of shaded illustrations used to measure the opacity of air pollution emissions, ranging from light gray through black; used to set and enforce emissions standards.

Riparian Habitat: Areas adjacent to rivers and streams with a differing density, diversity, and productivity of plant and animal species relative to nearby uplands.

Riparian Rights: Entitlement of a land owner to certain uses of water on or bordering the property, including the right to prevent diversion or misuse of upstream waters. Generally a matter of state law.

Risk: A measure of the probability that damage to life, health, property, and/or the environment will occur as a result of a given hazard.

Risk (Adverse) for Endangered Species: Risk to aquatic species if anticipated pesticide residue levels equal one-fifth of LD10 or one-tenth of LC50; risk to terrestrial species if anticipated pesticide residue levels equal one-fifth of LC10 or one-tenth of LC50.

Risk Assessment: Qualitative and quantitative evaluation of the risk posed to human health and/or the environment by the actual or potential presence and/or use of specific pollutants.

Risk Characterization:
The last phase of the risk assessment process that estimates the potential for adverse health or ecological effects to occur from exposure to a stressor and evaluates the uncertainty involved.

Risk Communication:
The exchange of information about health or environmental risks among risk assessors and managers, the general public, news media, interest groups, etc.

Risk Estimate:
A description of the probability that organisms exposed to a specific dose of a chemical or another pollutant will develop an adverse response, e.g., cancer.

Risk Factor: Characteristics (e.g., race, sex, age, obesity) or variables (e.g., smoking, occupational exposure level) associated with increased probability of a toxic effect.

Risk for Non-Endangered Species:
Risk to species if anticipated pesticide residue levels are equal to or greater than LC50.

Risk Management: The process of evaluating and selecting alternative regulatory and non-regulatory responses to risk. The selection process necessarily requires the consideration of legal, economic, and behavioral factors.

Risk-based Targeting:
The direction of resources to those areas that have been identified as having the highest potential or actual adverse effect on human health and/or the environment.

Risk-Specific Dose: The dose associated with a specified risk level.

River Basin:
The land area drained by a river and its tributaries.

A chemical or agent used to destroy rats or other rodent pests, or to prevent them from damaging food, crops, etc.

Rotary Kiln Incinerator: An incinerator with a rotating combustion chamber that keeps waste moving, thereby allowing it to vaporize for easier burning.

Rough Fish: Fish not prized for sport or eating, such as gar and suckers. Most are more tolerant of changing environmental conditions than are game or food species.

Route of Exposure: The avenue by which a chemical comes into contact with an organism, e.g., inhalation, ingestion, dermal contact, injection.

RTG (A Regional Transmission Group):
A voluntary organization of transmission owners, users, and other entities interested in coordinating transmission planning, expansion, operation, and use on a regional and inter-regional basis. Such groups are subject to FERC approval.

Rubbish: Solid waste, excluding food waste and ashes, from homes, institutions, and workplaces.

Rules Of Conduct: Rules set in advance to delineate acceptable activities by participants, particular participants with significant market power.

Rural Electric Cooperative: A non-profit, customer-owned electric utility that distributes power in a rural area.

Run-Off: That part of precipitation, snow melt, or irrigation water that runs off the land into streams or other surface-water. It can carry pollutants from the air and land into receiving waters.

Running Losses: Evaporation of motor vehicle fuel from the fuel tank while the vehicle is in use.

Sacrificial Anode: An easily corroded material deliberately installed in a pipe or intake to give it up (sacrifice it) to corrosion while the rest of the water supply facility remains relatively corrosion-free.

Sae Viscosity Number: A system established by the Society of Automotive Engineers for classifying crankcase oils and automotive transmission and differential lubricants according to their viscosities.

Safe: Condition of exposure under which there is a practical certainty that no harm will result to exposed individuals.

Safe Water: Water that does not contain harmful bacteria, toxic materials, or chemicals, and is considered safe for drinking even if it may have taste, odor, color, and certain mineral problems.

Safe Yield: The annual amount of water that can be taken from a source of supply over a period of years without depleting that source beyond its ability to be replenished naturally in "wet years."

Safener: A chemical added to a pesticide to keep it from injuring plants.

Salinity: The percentage of salt in water.

Salt Water Intrusion:
The invasion of fresh surface or ground water by salt water. If it comes from the ocean it may be called sea water intrusion.

Salts: Minerals that water picks up as it passes through the air, over and under the ground, or from households and industry.

Salvage: The utilization of waste materials.

Sampling Frequency: The interval between the collection of successive samples.

Sanctions: Actions taken by the federal government for failure to provide or implement a State Implementation Plan (SIP). Such action may include withholding of highway funds and a ban on construction of new sources of potential pollution.

Sand Filters:
Devices that remove some suspended solids from sewage. Air and bacteria decompose additional wastes filtering through the sand so that cleaner water drains from the bed.

Sanitary landfill: An engineered method of disposing of solid waste on land, in a manner that meets most of the standard specifications, including sound siting, extensive site preparation, proper leachate and gas management and monitoring, compaction, daily and final cover, complete access control, and record-keeping.

Sanitary Sewers: Underground pipes that carry off only domestic or industrial waste, not storm water.

Sanitary Survey: An on-site review of the water sources, facilities, equipment, operation and maintenance of a public water system to evaluate the adequacy of those elements for producing and distributing safe drinking water.

Sanitary Water (Also known as gray water):
Water discharged from sinks, showers, kitchens, or other non-industrial operations, but not from commodes.

Sanitation: Control of physical factors in the human environment that could harm development, health, or survival.

Saprolite: A soft, clay-rich, thoroughly decomposed rock formed in place by chemical weathering of igneous or metamorphic rock. Forms in humid, tropical, or subtropical climates.

Saprophytes: Organisms living on dead or decaying organic matter that help natural decomposition of organic matter in water.

Saturated Zone:
The area below the water table where all open spaces are filled with water under pressure equal to or greater than that of the atmosphere.

The condition of a liquid when it has taken into solution the maximum possible quantity of a given substance at a given temperature and pressure.

Scale House: A scale house can be found at either a landfill or a transfer station. It is the office, located a short distance from the main entrance, where all incoming vehicles must stop to be weighed or measured and receive a disposal ticket.

Scheduling Coordinator:
Scheduling coordinators (SCs) submit balanced schedules and provide settlement-ready meter data to the ISO. Scheduling coordinators also:

• Settle with generators and retailers, the PX and the ISO

• Maintain a year-round, 24-hour scheduling center

• Provide non-emergency operating instructions to generators and retailers

• Transfer schedules in and out of the PX. (The PX is a marketplace. As bids are accepted, power is being bought and sold. Once a bid is accepted, the power sold is "transferred out" of the PX, since is it no longer available. The power that is available for sale is "transferred in" to the PX. These transfers may also take place directly between the buyer and seller, without the involvement of the PX.)

The PX is considered a scheduling coordinator

Science Advisory Board (SAB): A group of external scientists who advise EPA on science and policy.

Scrap: Materials discarded from manufacturing operations that may be suitable for reprocessing.

Scrap Metal Processor:
The intermediate operating facility where recovered metal is sorted, cleaned of contaminants, and prepared for recycling.

Screen: A type of large sieve used to sort and separate different types of waste.

Use of screens to remove coarse floating and suspended solids from sewage.

Screening Risk Assessment:
A risk assessment performed with few data and many assumptions to identify exposures that should be evaluated more carefully for potential risk.

Scrubber: An air pollution device that uses a spray of water or reactant or a dry process to trap pollutants in emissions.

Seasonal Efficiency (SE):
A measure of the percentage of heat from the combustion of gas and from associated electrical equipment which is transferred to the space being heated during a year under specified conditions.

Seasonal Energy Efficiency Ratio (SEER):
The total cooling output of a central air conditioning unit in Btus during its normal usage period for cooling divided by the total electrical energy input in watt-hours during the same period, as determined using specified federal test procedures.

Secondary Drinking Water Regulations:
Non-enforceable regulations applying to public water systems and specifying the maximum contamination levels that, in the judgment of EPA, are required to protect the public welfare. These regulations apply to any contaminants that may adversely affect the odor or appearance of such water and consequently may cause people served by the system to discontinue its use.

Secondary Effect: Action of a stressor on supporting components of the ecosystem, which in turn impact the ecological component of concern.

Secondary Materials:
Materials that have been manufactured and used at least once and are to be used again.

Secondary Standards: National ambient air quality standards designed to protect the welfare, including effects on soils, water, crops, vegetation, man-made (anthropogenic) materials, animals, wildlife, weather, visibility, and climate; damage to property; transportation hazards; economic values, and personal comfort and well-being.

Secondary Treatment: The second step in most publicly owned waste treatment systems in which bacteria consume the organic parts of the waste. It is accomplished by bringing together waste, bacteria, and oxygen in trickling filters or in the activated sludge process. This treatment removes floating and settleable solids and about 90 percent of the oxygen-demanding substances and suspended solids. Disinfection is the final stage of secondary treatment.

Secure Landfill: A disposal facility designed to permanently isolate wastes from the environment. This entails burial of the wastes in a landfill that includes clay and/ or synthetic liners, leachate collection, gas collection (in cases where gas is generated), and an impermeable cover.

Secure Maximum Contaminant Level: Maximum permissible level of a contaminant in water delivered to the free-flowing outlet of the ultimate user, or of contamination resulting from corrosion of piping and plumbing caused by water quality.

Securitize: The aggregation of contracts for the purchase of the power output from various energy projects into one pool which then offers shares for sale in the investment market. This strategy diversifies project risks from what they would be if each project were financed individually, thereby reducing the cost of financing. Fannie Mae performs such a function in the home mortgage market.

Sediment: Topsoil, sand, and minerals washed from the land into water, usually after rain or snow melt.

Sediment Yield: The quantity of sediment arriving at a specific location.

Sedimentation: Letting solids settle out of wastewater by gravity during treatment.

Sedimentation Tanks: Wastewater tanks in which floating wastes are skimmed off and settled solids are removed for disposal.

Sediments: Soil, sand, and minerals washed from land into water, usually after rain. They pile up in reservoirs, rivers, and harbors, destroying fish and wildlife habitat, and clouding the water so that sunlight cannot reach aquatic plants. Careless farming, mining, and building activities will expose sediment materials, allowing them to wash off the land after rainfall.

Seed Protectant: A chemical applied before planting to protect seeds and seedlings from disease or insects.

Seepage: Percolation of water through the soil from unlined canals, ditches, laterals, watercourses, or water storage facilities.

Selective Pesticide: A chemical designed to affect only certain types of pests, leaving other plants and animals unharmed.

Self-Generation: A generation facility dedicated to serving a particular retail customer, usually located on the customer's premises. The facility may either be owned directly by the retail customer or owned by a third party with a contractual arrangement to provide electricity to meet some or all of the customer's load.

Self-Service Wheeling: Primarily an accounting policy comparable to net-billing or running the meter backward. An entity owns generation that produces excess electricity at one site that is used at another site owned by the same entity. It is given billing credit for the excess electricity (displacing retail electricity costs minus wheeling charges) on the bills for its other sites.

Semi-Confined Aquifer: An aquifer partially confined by soil layers of low permeability through which recharge and discharge can still occur.

Semivolatile Organic Compounds: Organic compounds that volatilize slowly at standard temperature (20 degrees C and 1 atm pressure).

Senescence: The aging process. It is Sometimes used to describe lakes or other bodies of water in advanced stages of eutrophication. It is also used to describe plants and animals.

Sensible Heat: Heat that results in a temperature change.

Septage: Sludge removed from a septic tank (a chamber that holds human excreta).

Septic System:
An on-site system designed to treat and dispose of domestic sewage. A typical septic system consists of the tank that receives waste from a residence or business and a system of tile lines or a pit for disposal of the liquid effluent (sludge) that remains after decomposition of the solids by bacteria in the tank and must be pumped out periodically.

Septic Tank: An underground storage tank for wastes from homes not connected to a sewer line. Waste goes directly from the home to the tank.

Service Area: Any contiguous geographic area serviced by the same electric utility.

Service Connector:
The pipe that carries tap water from a public water main to a building.

Service Line Sample: A one-liter sample of water that has been standing for at least 6 hours in a service pipeline and is collected according to federal regulations.

Service Pipe: The pipeline extending from the water main to the building served or to the consumer's system.

Set-Back: Setting a thermometer to a lower temperature when the building is unoccupied to reduce consumption of heating energy. Also, refers to setting the thermometer to a higher temperature during unoccupied periods in the cooling season.

Set-Out Container: A box or bucket used for residential waste that is placed outside for collection.

Set Point: Scheduled operating level for each generating unit or other resource scheduled to run in the Hour-ahead Schedule.

Settleable Solids: Material heavy enough to sink to the bottom of a wastewater treatment tank.

Settlement: The process of financial settlement for products and services purchased and sold. Each settlement involves a price and quantity. Both the ISO and PX may perform settlement functions.

Settling Chamber: A series of screens placed in the way of flue gasses to slow the stream of air, thus helping gravity to pull particles into a collection device.

Settling Tank: A holding area for wastewater, where heavier particles sink to the bottom for removal and disposal.

Sewage: The waste and wastewater produced by residential and commercial sources and discharged into sewers.

Sewage Sludge: Sludge produced at a Publicly Owned Treatment Works, the disposal of which is regulated under the Clean Water Act.

Sewage Sludge: A semi-liquid residue that settles to the bottom of canals and pipes carrying sewage or industrial wastewaters, or in the bottom of tanks used in treating wastewaters.

Sewer: A channel or conduit that carries wastewater and storm-water runoff from the source to a treatment plant or receiving stream. "Sanitary" sewers carry household, industrial, and commercial waste. "Storm" sewers carry runoff from rain or snow. "Combined" sewers handle both.

Sewer Cleaning Waste: Waste produced by the cleaning and maintenance of wastewater and storm water collection systems. It is predominantly organic (sludge, fats, waste from screening operations at wastewater treatment plants, oil, grease and night soil, etc.) and mineral waste (wastewater treatment sand and grit, sludge, sewer cleaning sand, residue from dredging rivers and canals).

Sewerage: The entire system of sewage collection, treatment, and disposal.

Shade Screen: A screen affixed to the exterior of a window or other glazed opening, designed to reduce the solar radiation reaching the glazing.

Shading: 1) The protection from heat gains due to direct solar radiation; 2) Shading is provided by (a) permanently attached exterior devices, glazing materials, adherent materials applied to the glazing, or an adjacent building for non-residential buildings, hotels, motels and high-rise apartments, and by (b) devices affixed to the structure for residential buildings.

Shading Coefficient: The ratio of solar heat gain through a specific glazing system to the total solar heat gain through a single layer of clear, double-strength glass.

Shading Coefficient:
The amount of the sun's heat transmitted through a given window compared with that of a standard 1/8- inch-thick single pane of glass under the same conditions.

Sharps: Hypodermic needles, syringes (with or without the attached needle), Pasteur pipettes, scalpel blades, blood vials, needles with attached tubing, and culture dishes used in animal or human patient care or treatment, or in medical, research or industrial laboratories. Also included are other types of broken or unbroken glassware that were in contact with infectious agents, such as used slides and cover slips, and unused hypodermic and suture needles, syringes, and scalpel blades.

Shock Load: The arrival at a water treatment plant of raw water containing unusual amounts of algae, colloidal matter. color, suspended solids, turbidity, or other pollutants.

Short-Circuiting: When some of the water in tanks or basins flows faster than the rest; may result in shorter contact, reaction, or settling times than calculated or presumed.

Sick Building Syndrome: Building whose occupants experience acute health and/or comfort effects that appear to be linked to time spent therein, but where no specific illness or cause can be identified. Complaints may be localized in a particular room or zone or may spread throughout the building.

Side Fins:
Vertical shading elements mounted on either side of a glazed opening that block direct solar radiation from the lower, lateral portions of the sun's path.

Signal: The volume or product-level change produced by a leak in a tank.

Signal Words: The words used on a pesticide label--Danger, Warning, Caution--to indicate a level of toxicity.

Significant Deterioration: Pollution resulting from a new source in previously "clean" areas.

Significant Municipal Facilities: Those publicly owned sewage treatment plants that discharge a million gallons per day or more and are therefore considered by states to have the potential to substantially affect the quality of receiving waters.

Significant Potential Source of Contamination: A facility or activity that stores, uses, or produces compounds with potential for significant contaminating impact if released into the source water of a public water supply.

Significant Violations: Violations by point source dischargers of sufficient magnitude or duration to be a regulatory priority.

Silt: Sedimentary materials composed of fine or intermediate-sized mineral particles.

Silviculture: Management of forest land for timber.

Single-Breath Canister: Small one-liter canister designed to capture a single breath. Used in air pollutant ingestion research.

Sink: Place in the environment where a compound or material collects.

Controlling oil spills by using an agent to trap the oil and sink it to the bottom of the body of water where the agent and the oil are biodegraded.

SIP Call: EPA action requiring a state to resubmit all or part of its State Implementation Plan to demonstrate attainment of the required national ambient air quality standards within the statutory deadline. A SIP Revision is a revision of a SIP altered at the request of EPA or on a state's initiative.

Site: Any location on which a facility is constructed or is proposed to be constructed.

Site Assessment Program: A means of evaluating hazardous waste sites through preliminary assessments and site inspections to develop a Hazard Ranking System score.

Site Energy: The energy consumed at a building location or other end-use site.

Site Inspection: The collection of information from a Superfund site to determine the extent and severity of hazards posed by the site. It follows and is more extensive than a preliminary assessment. The purpose is to gather information necessary to score the site, using the Hazard Ranking System, and to determine if it presents an immediate threat requiring prompt removal.

Site Remediation: Treatment of a contaminated site by removing contaminated solids or liquids or treating them on-site.

Site Safety Plan:
A crucial element in all removal actions, it includes information on equipment being used, precautions to be taken, and steps to take in the event of an on-site emergency.

Siting: The process of choosing a location for a facility.

Skimming: Using a machine to remove oil or scum from the surface of the water.

Skylight: Any opening in the roof surface which is glazed with a transparent or translucent material.

Sky Temperature: The equivalent temperature of the clouds, water vapor, and other atmospheric elements that make up the sky to which a surface can radiate heat.

Slow Sand Filtration: Passage of raw water through a bed of sand at low velocity, resulting in substantial removal of chemical and biological contaminants.

Sludge: A semi-solid residue from any of a number of air or water treatment processes; can be a hazardous waste.

Sludge: There are several different types of sludge depending on its source. Primary sludge is generated in the settler-digesters of wastewater treatment plants. It is rich in mineral substances such as microsand and earth and contains organic matter. Physical-chemical sludge is a variant of primary sludge obtained by the addition of reagents such as iron salt and aluminum to agglomerate the fine particles in wastewater. Biosolids, or secondary sludge, is generated by the biological treatment of wastewater. Sludge may be disposed of in four different ways depending on its quality and composition: land application, landfilling, incineration or composting.

Sludge Digester: Tank in which complex organic substances like sewage sludges are biologically dredged. During these reactions, energy is released and much of the sewage is converted to methane, carbon dioxide, and water.

Slurry: A watery mixture of insoluble matter resulting from some pollution control techniques.

Small Quantity Generator (SQG-sometimes referred to as "Squeegee"): Persons or enterprises that produce 220-2200 pounds per month of hazardous waste; they are required to keep more records than conditionally exempt generators. The largest category of hazardous waste generators, SQGs, include automotive shops, dry cleaners, photographic developers, and many other small businesses.

Smelter: A facility that melts or fuses ore, often with an accompanying chemical change, to separate its metal content. Emissions cause pollution. "Smelting" is the process involved.

Smog: Air pollution typically associated with oxidants.

Smog: Originally "smog" meant a mixture of smoke and fog. The definition has expanded to mean air that has restricted visibility due to pollution. Pollution formed in the presence of sunlight is called photochemical smog. According to the U.S. EPA, smog is "a mixture of pollutants, principally ground-level ozone, produced by chemical reactions in the air involving smog-forming chemicals. A major portion of smog-formers come from burning of petroleum-based fuels such as gasoline. Other smog-formers, volatile organic compounds, are found in products such as paints and solvents. Smog can harm health, damage the environment and cause poor visibility. Major smog occurrences are often linked to heavy motor vehicle traffic, the sunshine, high temperatures, and calm winds or temperature inversion (weather condition in which warm air is trapped close to the ground instead of rising). Smog is often worse away from the source of the smog-forming chemicals since the chemical reactions that result in smog occur in the sky while the reacting chemicals are being blown away from their sources by winds."

Smoke: Particles suspended in air after incomplete combustion.

Soft Detergents: Cleaning agents that break down in nature.

Soft Water:
Any water that does not contain a significant amount of dissolved minerals such as salts of calcium or magnesium.

Soil Adsorption Field: A sub-surface area containing a trench or bed with clean stones and a system of piping through which treated sewage may seep into the surrounding soil for further treatment and disposal.

Soil and Water Conservation Practices:
Control measures consisting of managerial, vegetative, and structural practices to reduce the loss of soil and water.

Soil Conditioner: An organic material like humus or compost that helps soil absorb water, build a bacterial community, and take up mineral nutrients.

Soil Erodibility:
An indicator of a soil's susceptibility to raindrop impact, runoff, and other erosive processes.

Soil Gas: Gaseous elements and compounds in the small spaces between particles of the earth and soil. Such gasses can be moved or driven out under pressure.

Soil Moisture:
The water contained in the pore space of the unsaturated zone.

Soil Sterilant:
A chemical that temporarily or permanently prevents the growth of all plants and animals.


Solar Cell: A photovoltaic cell that can convert light directly into electricity. A typical solar cell uses semiconductors made from silicon.

Solar Collector: A component of an active or passive solar system that absorbs solar radiation to heat a transfer medium which, in turn, supplies heat energy to space or water heating system.

Solar Collector:
A surface or device that absorbs solar heat and transfers it to a fluid. The heated fluid then is used to move the heat energy to where it will be useful, such as in water or space heating equipment.

Solar Energy: Heat and light radiated from the sun.

Solar Energy Research Institute (SERI):
Established in 1974 and funded by the federal government, the institute's general purpose is to support U.S. Department of Energy's solar energy program and foster the widespread use of all aspects of solar technology, including photovoltaics, solar heating and cooling, solar thermal power generation, wind ocean thermal conversion and biomass conversion.

Solar Heat Gain: Heat added to space due to transmitted and absorbed solar energy.

Solar Heat Gain Factor:
An estimate used in calculating cooling loads of the heat gain due to transmitted and absorbed solar energy through 1/8"-thick, clear glass at a specific latitude, time and orientation.

Solar Heating And Hot Water Systems:
Solar heating or hot water systems provide two basic functions: (a) capturing the sun's radiant energy, converting it into heat energy, and storing this heat in insulated storage tank(s); and (b) delivering the stored energy as needed to either the domestic hot water or heating system. These components are called the collection and delivery subsystems.

Solar Irradiation:
The amount of radiation, both direct and diffuse, that can be received at any given location.

Solar Power: Electricity generated from solar radiation.

Solar Radiation: Electromagnetic radiation emitted by the sun.

Solar Satellite Power:
A proposed process of using satellites in geosynchronous orbit above the earth to capture solar energy with photovoltaic cells, convert it to microwave energy, beam the microwaves to earth where they would be received by large antennas, and changed from microwave into usable electricity.

Solar Thermal Power Plant:
Means a thermal power plant in which 75 percent or more of the total energy output is from solar energy and the use of backup fuels, such as oil, natural gas, and coal, does not, in the aggregate, exceed 25 percent of the total energy input of the facility during any calendar year period.

Solar Thermal: The process of concentrating sunlight on a relatively small area to create the high temperatures needs to vaporize water or other fluids to drive a turbine for generation of electric power.

Solder: A metallic compound used to seal joints between pipes. Until recently, most solders contained 50 percent lead. Use of solder containing more than 0.2 percent lead in pipes carrying drinking water is now prohibited.

Sole-Source Aquifer:
An aquifer that supplies 50-percent or more of the drinking water of an area.

Solid Waste: Non-liquid, non-soluble materials ranging from municipal garbage to industrial wastes that contain complex and sometimes hazardous substances. Solid wastes also include sewage sludge, agricultural refuse, demolition wastes, and mining residues. Technically, solid waste also refers to liquids and gasses in containers.

Solid Waste Disposal:
The final placement of refuse that is not salvaged or recycled.

Solid Waste Management:
Supervised handling of waste materials from their source through recovery processes to disposal.

Solidification and Stabilization: Removal of wastewater from a waste or changing it chemically to make it less permeable and susceptible to transport by water.

Solubility: The amount of mass of a compound that will dissolve in a unit volume of solution. Aqueous Solubility is the maximum concentration of a chemical that will dissolve in pure water at a reference temperature.

Soot: Carbon dust formed by incomplete combustion.

Sorption: The action of soaking up or attracting substances; the process used in many pollution control systems.

The sorting of mixed waste into different categories (cardboard, plastics, and wooden pallets) with a view to facilitating treatment through processes specific to each category.

Sorting Rejects: Materials not recovered during industrial sorting. Some rejects can be subjected to treatment later.

Sound Pressure Level (dB(A)):
A-weighted sound pressure level at a certain distance from the source.

Source Area:
The location of liquid hydrocarbons or the zone of highest soil or groundwater concentrations, or both, of the chemical of concern.

Source Characterization Measurements:
Measurements made to estimate the rate of release of pollutants into the environment from a source such as an incinerator, landfill, etc.

Source Energy:
All the energy used in delivering energy to a site, including power generation and transmission and distribution losses, to perform a specific function, such as space conditioning, lighting, or water heating. Approximately three watts (or 10.239 Btus) of energy is consumed to deliver one watt of usable electricity.

Source Reduction:
Reducing a number of materials entering the waste stream from a specific source by redesigning products or patterns of production or consumption (e.g., using returnable beverage containers). It is synonymous with waste reduction.

Source Separation:
Segregating various wastes at the point of generation (e.g., separation of paper, metal and glass from other wastes to make recycling simpler and more efficient).

Source-Water Protection Area:
The area delineated by a state for a Public Water Supply or including numerous such suppliers, whether the source is ground water or surface water or both.

Sparge or Sparging:
Injection of air below the water table to strip dissolved volatile organic compounds and/or oxygenate ground water to facilitate aerobic biodegradation of organic compounds.

Special Contracts: Any contract that provides a utility service under terms and conditions other than those listed in the utility's tariffs. For example, an electric utility may enter into an agreement with a large customer to provide electricity at a rate below the tariffed rate in order to prevent the customer from taking advantage of some other option that would result in the loss of the customer's load. This generally allows that customer to compete more effectively in their product market.

Special Local-Needs Registration:
Registration of a pesticide product by a state agency for a specific use that is not federally registered. However, the active ingredient must be federally registered for other uses. The special use is specific to that state and is often minor, thus may not warrant the additional cost of a full federal registration process. SLN registration cannot be issued for new active ingredients, food-use active ingredients without tolerances, or for a canceled registration. The products cannot be shipped across state lines.

Special Review: Formerly known as Rebuttable Presumption Against Registration (RPAR), this is the regulatory process through which existing pesticides suspected of posing unreasonable risks to human health, non-target organisms, or the environment are referred for review by EPA. Such review requires an intensive risk/benefit analysis with opportunity for public comment. If the risk is found to outweigh social and economic benefits, regulatory actions can be initiated, ranging from label revisions and use-restriction to cancellation or suspended registration.

Special Waste: Items such as household hazardous waste, bulky wastes (refrigerators, pieces of furniture, etc.) tires, and used oil.

Special Wastes:
Wastes that are ideally considered to be outside of the MSW stream, but which sometimes enter it and must often be dealt with by municipal authorities. These include household hazardous waste, medical waste, construction and demolition debris, war and earthquake debris, tires, oils, wet batteries, sewage sludge, human excreta, slaughterhouse waste, and industrial waste. Any waste that requires special handling. Special waste is non-hazardous waste generally from an industrial generator and must be profiled to ensure that it does not contain elevated levels of potentially hazardous chemicals or materials.

1. A reproductively isolated aggregate of interbreeding organisms having common attributes and usually designated by a common name.2. An organism belonging to belonging to such a category.

Specific Conductance:
Rapid method of estimating the dissolved solid content of a water supply by testing its capacity to carry an electrical current.

Specific Heat:
In English units, the quantity of heat, in Btu, needed to raise the temperature of one pound of material one degree Fahrenheit.

Specific Yield: The amount of water a unit volume of saturated permeable rock will yield when drained by gravity.

Spill Prevention, Containment, and Countermeasures Plan (SPCP):
Plan covering the release of hazardous substances as defined in the Clean Water Act.

Split-The-Savings (Electric Utility):
The basis for settling economy-energy transactions between utilities. The added costs of the supplier are subtracted from the avoided costs of the buyer, and the difference is evenly divided.

Dirt or rock removed from its original location--destroying the composition of the soil in the process--as in strip-mining, dredging, or construction.

Spray Tower Scrubber: A device that sprays alkaline water into a chamber where acid gasses are present to aid in neutralizing the gas.

Spring: Ground water seeping out of the earth where the water table intersects the ground surface.

Spring Melt/Thaw:
The process whereby warm temperatures melt winter snow and ice. Because various forms of acid deposition may have been stored in the frozen water, the melt can result in abnormally large amounts of acidity entering streams and rivers, sometimes causing fish kills.

Conversion of the active organic matter in sludge into inert, harmless material.

Stable Air: A motionless mass of air that holds, instead of dispersing, pollutants.

Stack: A chimney, smokestack, or vertical pipe that discharges used air.

Stack Effect:
Air, as in a chimney, that moves upward because it is warmer than the ambient atmosphere.

Stack Effect: Flow of air resulting from warm air rising, creating a positive pressure area at the top of a building and negative pressure area at the bottom. This effect can overpower the mechanical system and disrupt building ventilation and air circulation.

Stage II Controls: Systems placed on service station gasoline pumps to control and capture gasoline vapors during refueling.

Stagnation: Lack of motion in a mass of air or water that holds pollutants in place.

Stakeholder: Any organization, governmental entity, or individual that has a stake in or may be impacted by a given approach to environmental regulation, pollution prevention, energy conservation, etc.

Standard Industrial Classification Code:
Also known as SIC Codes, a method of grouping industries with similar products or services and assigning codes to these groups.

Standard Reference Conditions:
Standard conditions for ambient air, ambient air pressure, relative humidity, cooling water temperature referred to when defining engine output, fuel consumption etc.

Standard Sample: The part of finished drinking water that is examined for the presence of coliform bacteria.

Standards: Norms that impose limits on the amount of pollutants or emissions produced. EPA establishes minimum standards, but states are allowed to be stricter.

Standby Loss: A measure of the losses from a water heater tank. When expressed as a percentage, standby loss is the ratio of heat loss per hour to the heat content of the stored water above room temperature. When expressed in watts, standby loss is the heat lost per hour, per square foot of tank surface area.

Start of a Response Action:
The point in time when there is a guarantee or set-aside of funding by EPA, other federal agencies, states or Principal Responsible Parties in order to begin response actions at a Superfund site.

State Emergency Response Commission (SERC):
Commission appointed by each state governor according to the requirements of SARA Title III. The SERCs designate emergency planning districts, appoint local emergency planning committees, and supervise and coordinate their activities.

State Environmental Goals and Indication Project:
Program to assist state environmental agencies by providing technical and financial assistance in the development of environmental goals and indicators.

State Implementation Plans (SIP):
EPA approved state plans for the establishment, regulation, and enforcement of air pollution standards.

State Management Plan:
Under FIFRA, a state management plan required by EPA to allow states, tribes, and U.S. territories the flexibility to design and implement ways to protect ground water from the use of certain pesticides.

Static Water Depth:
The vertical distance from the centerline of the pump discharge down to the surface level of the free pool while no water is being drawn from the pool or water table.

Static Water Level:
1. Elevation or level of the water table in a well when the pump is not operating. 2. The level or elevation to which water would rise in a tube connected to an artesian aquifer or basin in a conduit under pressure.

Stationary Source: A fixed-site producer of pollution, mainly power plants and other facilities using industrial combustion processes.

Steady State Efficiency:
A performance rating for space heaters; a measure of the percentage of heat from combustion of gas which is transferred to the space being heated under specified steady state conditions.

Steam Electric Plant:
A power station in which steam is used to turn the turbines that generate electricity. The heat used to make the steam may come from burning fossil fuel, using a controlled nuclear reaction, concentrating the sun's energy, tapping the earth's natural heat or capturing industrial waste heat.

Sterilization: The removal or destruction of all microorganisms, including pathogenic and other bacteria, vegetative forms, and spores.

Sterilizer: One of three groups of antimicrobials registered by EPA for public health uses. EPA considers an antimicrobial to be a sterilizer when it destroys or eliminates all forms of bacteria, viruses, and fungi and their spores. Because spores are considered the most difficult form of microorganism to destroy, EPA considers the term sporicide to be synonymous with sterilizer.

Stirling Engine: An external combustion engine that converts heat into useable mechanical energy (shaft work) by the heating (expanding) and cooling (contracting) of a captive gas such as helium or hydrogen.

Stoichiometric: Stoichiometric is often used in thermodynamics to refer to the "perfect mixture" of a fuel and air.

Stoker (Wheelabrator):
A grating system used to combust refuse in a controlled fashion.

The temporary holding of waste pending treatment or disposal, as in containers, tanks, waste piles, and surface impoundments.

Storage Type Water Heater:
A water heater that heats and stores water at a thermostatically controlled temperature for delivery on demand.

Storm Sewer:
A system of pipes (separate from sanitary sewers) that carries water runoff from buildings and land surfaces.

Strategic Petroleum Reserve:
The strategic petroleum reserve consists of government owned and controlled crude oil stockpiles stored at various locations in the Gulf Coast region of the country. These reserves can be drawn down in response to sever oil supply disruptions. The target is to have a reserve of 750 million barrels of oil. Use of the reserve must be authorized by the President of the United States.

Stratification: Separating into layers.

Study of the formation, composition, and sequence of sediments, whether consolidated or not.

Stratosphere: The portion of the atmosphere 10-to-25 miles above the earth's surface.

Stressors: Physical, chemical, or biological entities that can induce adverse effects on ecosystems or human health.

Growing crops in a systematic arrangement of strips or bands that serve as barriers to wind and water erosion.

A process that uses machines to scrape soil or rock away from mineral deposits just under the earth's surface.

Structural Deformation: Distortion in walls of a tank after the liquid has been added or removed.

Subcell: A pit into which waste is deposited in a landfill. Landfills are divided into cells, which are subdivided into subcells.

Subchronic: Of intermediate duration, usually used to describe studies or periods of exposure lasting between 5 and 90 days.

Subchronic Exposure:
Multiple or continuous exposures lasting for approximately ten percent of an experimental species lifetime, usually over a three-month period.

Submerged Aquatic Vegetation:
Vegetation that lives at or below the water surface; an important habitat for young fish and other aquatic organisms.

Subsidy: Direct or indirect payment from the government to businesses, citizens, or institutions to encourage the desired activity.

A facility that steps up or steps down the voltage in utility power lines. Voltage is stepped up where power is sent through long-distance transmission lines. it is stepped down where the power is to enter local distribution lines.

Subtitle D:
The Federal rules and regulations that govern the environmental operations of MSW landfills.

Subwatershed: The topographic perimeter of the catchment area of a stream tributary.

Sulfur Dioxide (SO2):
A pungent, colorless, gas formed primarily by the combustion of fossil fuels; becomes a pollutant when present in large amounts.

Sump: A pit or tank that catches liquid runoff for drainage or disposal.

Sunk Cost:
In economics, a sunk cost is a cost that has already been incurred, and therefore cannot be avoided by any strategy going forward.

Chlorination with doses that are deliberately selected to produce water free of combined residuals so large as to require dechlorination.

A synthetic material that has very low or no electrical resistance. Such experimental materials are being investigated in laboratories to see if they can be created at near room temperatures. If such a superconductor can be found, electrical transmission lines with no little or no resistance may be built, thus conserving energy usually lost in transmission. Superconductors could also have used in computer chips, solid state devices, and electrical motors or generators.

Supercritical Water:
A type of thermal treatment using moderate temperatures and high pressures to enhance the ability of water to break down large organic molecules into smaller, less toxic ones. Oxygen injected during this process combines with simple organic compounds to form carbon dioxide and water.

Superfund: The program operated under the legislative authority of CERCLA and SARA that funds and carries out EPA solid waste emergency and long-term removal and remedial activities. These activities include establishing the National Priorities List, investigating sites for inclusion on the list, determining their priority, and conducting and/or supervising cleanup and other remedial actions.

Superfund Innovative Technology Evaluation (SITE) Program: EPA program to promote development and use of innovative treatment and site characterization technologies in Superfund site cleanups.

Supertanker: A very large ship designed to transport more than 500,000 deadweight tonnage of oil.

Supplemental Registration:
An arrangement whereby a registrant licenses another company to market its pesticide product under the second company's registration.

Supplier of Water:
Any person who owns or operates a public water supply.

Supply Bid: A bid into the PX indicating a price at which a seller is prepared to sell energy or ancillary services.

Supply-Side: Activities conducted on the utility's side of the customer meter. Activities designed to supply electric power to customers, rather than meeting load though energy efficiency measures or on-site generation on the customer side of the meter.

Surface Impoundment: Treatment, storage, or disposal of liquid hazardous wastes in ponds.

Surface Runoff:
Precipitation, snow melt, or irrigation water in excess of what can infiltrate the soil surface and be stored in small surface depressions; a major transporter of non-point source pollutants in rivers, streams, and lakes. 

Surface Uranium Mines:
Strip mining operations for removal of uranium-bearing ore.

Surface Water:
All water naturally open to the atmosphere (rivers, lakes, reservoirs, ponds, streams, impoundments, seas, estuaries, etc.)

Surface-Water Treatment Rule:
Rule that specifies maximum contaminant level goals for Giardia lamblia, viruses, and Legionella and promulgates filtration and disinfection requirements for public water systems using surface-water or ground-water sources under the direct influence of surface water. The regulations also specify water quality, treatment, and watershed protection criteria under which filtration may be avoided.

Surfacing ACM: Asbestos-containing material that is sprayed or troweled on or otherwise applied to surfaces, such as acoustical plaster on ceilings and fireproofing materials on structural members.

Surfacing Material: Material sprayed or troweled onto structural members (beams, columns, or decking) for fire protection; or on ceilings or walls for fireproofing, acoustical or decorative purposes. Includes textured plaster, and other textured wall and ceiling surfaces.

Surfactant: A detergent compound that promotes lathering.

Surplus (Electric Utility): Excess firm energy available from a utility or region for which there is no market at the established rates.

Surrogate Data: Data from studies of test organisms or a test substance that are used to estimate the characteristics or effects on another organism or substance.

Surveillance System: A series of monitoring devices designed to check on environmental conditions.

Susceptibility Analysis: An analysis to determine whether a Public Water Supply is subject to significant pollution from known potential sources.

Suspect Material:
Building material suspected of containing asbestos; e.g., surfacing material, floor tile, ceiling tile, thermal system insulation.

Suspended Loads: Specific sediment particles maintained in the water column by turbulence and carried with the flow of water.

Suspended Solids: Small particles of solid pollutants that float on the surface of, or are suspended in, sewage or other liquids. They resist removal by conventional means.

Suspending the use of a pesticide when EPA deems it necessary to prevent an imminent hazard resulting from its continued use. An emergency suspension takes effect immediately; under an ordinary suspension, a registrant can request a hearing before the suspension goes into effect. Such a hearing process might take six months.

Suspension Culture: Cells growing in a liquid nutrient medium.

Sustainability: The characteristics of a product, material or process to be sustainable.

Sustainable: Of, relating to, or being a method of harvesting or using a resource so that the resource is not depleted or permanently damaged.

Sustainable Development: Sustainable development focuses on three areas: environmental protection, social improvement, and economic development. Production and consumption methods must respect the human and natural environment so that all earth's inhabitants can meet their fundamental needs (food, accommodation, clothing, education, work and living in a healthy environment). Sustainable development education is the only way to bring about a change in attitudes and behavior. Not only people but also companies, municipalities, governments and international institutions must change in order to combat the threats to the earth (social inequalities, industrial and health risks, climate change and loss of biodiversity).

Sustainable Practice: A practice (such as manufacturing) that maintains a given condition without destroying or depleting natural resources.

Sustainable Product: A product that has no negative impact on natural ecosystems or resources.

Sustained Orderly Development:
A condition in which a growing and stable market are identified by orders that are placed on a reliable schedule. The orders increase in magnitude as previous deliveries and engineering and field experience lead to further reductions in costs. The reliability of these orders can be projected many years into the future, on the basis of long-term contracts, to minimize market risks and investor exposure.

Swamp: A type of wetland dominated by woody vegetation but without appreciable peat deposits. Swamps may be fresh or salt water and tidal or non-tidal.

Syncrude: Synthetic crude oil made from coal of from oil shale.

Synergism: An interaction of two or more chemicals that results in an effect greater than the sum of their separate effects.

Synfuel: Synthetic gas or synthetic oil. Fuel that is artificially made as contrasted to that which is found in nature. The synthetic gas made from coal is considered to be more economical and easier to produce than synthetic oil. When natural gas supplies in the earth are being depleted, it is expected that synthetic gas will be able to be used widely as a substitute fuel.

Syngas: Synthetic gas makes from coal. A mixture of light, combustible gasses produced by the advanced conversion technology (gasification or pyrolysis).

Synthetic Organic Chemicals (SOCs): Man-made (anthropogenic) organic chemicals. Some SOCs are volatile; others tend to stay dissolved in water instead of evaporating.

System: A combination of equipment and/or controls, accessories, interconnecting means and terminal elements by which energy is transformed to perform a specific function, such as climate control, service water heating, or lighting.

System Integration (Of New Technologies):
The successful integration of a new technology into the electric utility system by analyzing the technology's system effects and resolving any negative impacts that might result from its broader use.

System With a Single Service Connection:
A system that supplies drinking water to consumers via a single service line.

Systemic Pesticide:
A chemical absorbed by an organism that interacts with the organism and makes the organism toxic to pests.

Tail Water: The runoff of irrigation water from the lower end of an irrigated field.

Residue of raw material or waste separated out during the processing of crops or mineral ores.

Tailpipe Standards: Emissions limitations applicable to mobile source engine exhausts.

Take-Out Point:
The metering points at which a metered entity takes delivery of energy.

Adjusting, negating, or removing pollution control equipment on a motor vehicle.

Tar Sands: Sedimentary rocks containing heavy oil that cannot be extracted by conventional petroleum recovery methods.

Tariff: A document, approved by the responsible regulatory agency, listing the terms and conditions, including a schedule of prices, under which utility services will be provided.

Task Lighting (Task-Oriented Lighting):
Lighting designed specifically to illuminate one or more task locations, and generally confined to those locations.

Technical Assistance Grant (TAG):
As part of the Superfund program, Technical Assistance Grants of up to $50,000 are provided to citizens' groups to obtain assistance in interpreting information related to clean-ups at Superfund sites or those proposed for the National Priorities List. Grants are used by such groups to hire technical advisors to help them understand the site-related technical information for the duration of response activities.

Technical-Grade Active Ingredient (TGA):
A pesticide chemical in pure form as it is manufactured prior to being formulated into an end-use product (e.g. wettable powders, granules, emulsifiable concentrates). Registered manufactured products composed of such chemicals are known as Technical Grade Products.

Technology-Based Limitations:
Industry-specific effluent limitations based on best available preventive technology applied to a discharge when it will not cause a violation of water quality standards at low stream flows. Usually applied to discharges into large rivers.

Technology-Based Standards:
Industry-specific effluent limitations applicable to direct and indirect sources which are developed on a category-by-category basis using statutory factors, not including water-quality effects.

Degree of hotness or coldness measured on one of the several arbitrary scales based on some observable phenomenon (such as the expansion).

A substance capable of causing birth defects.

The introduction of nonhereditary birth defects in a developing fetus by exogenous factors such as physical or chemical agents acting in the womb to interfere with normal embryonic development.

Terracing: Dikes built along the contour of sloping farm land that holds runoff and sediment to reduce erosion.

Tertiary Amyl Methyl Ether (TAME): Another oxygenate that can be used in reformulated gasoline. It is an ether based on reactive C5 olefins and methanol.

Tertiary Treatment:
Advanced cleaning of wastewater that goes beyond the secondary or biological stage, removing nutrients such as phosphorus, nitrogen, and most BOD and suspended solids.

The Electrical Grid: Continuing the water analogy, envision the electrical grid as a big pressurized water system with hundreds of pumps (generators) pumping water into the system through long pipes (transmission lines), and literally millions of customers sucking water out through smaller straws (utility distribution systems). There are hundreds of places (substations) where valves and adapters (switches and transformers) are used to break the large volumes of water down into smaller units under less pressure for delivery through the straws. The ISO’s job is to make sure that in the high-pressure system, the water pressure (voltage) and the RPMs of all the pumps (frequency) remain constant, even though inflow and outflow (measured in wattage) are both changing minute by minute.

Theoretical Maximum Residue Contribution:
The theoretical maximum amount of a pesticide in the daily diet of an average person. It assumes that the diet is composed of all food items for which there are tolerance-level residues of the pesticide. The TMRC is expressed as milligrams of pesticide/kilograms of body weight/day.

Therapeutic Index:
The ratio of the dose required to produce toxic or lethal effects to the dose required to produce the non-adverse or therapeutic response.

Therm: One hundred thousand (100,000) British thermal units (1 therm = 100,000 Btu).

Thermal Break (Thermal Barrier):
An element of low heat conductivity placed in such a way as to reduce or prevent the flow of heat. Some metal framed windows are designed with thermal breaks to improve their overall thermal performance.

Thermal Efficiency:
Quantity of heat produced in relation to fuel input.

Thermal (Energy) Storage:
A technology that lowers the amount of electricity needed for comfort conditioning during utility peak load periods. A building’s thermal energy storage system might, for example, use off-peak power to make ice or to chill water at night, later using the ice or chilled water in a power saving process for cooling during the day.

Thermal Mass: A material used to store heat, thereby slowing the temperature variation within a space. Typical thermal mass materials include concrete, brick, masonry, tile and mortar, water, and rock or other materials with high heat capacity.

Thermal Pollution:
Discharge of heated water from industrial processes that can kill or injure aquatic organisms.

Thermal Power Plant:
Any stationary or floating electrical generating facility using any source of thermal energy, with a generating capacity of 50 megawatts or more, and any facilities appurtenant thereto. Exploratory, development and production wells, resource transmission lines, and other related facilities used in connection with a geothermal exploratory project or a geothermal field development project are not appurtenant facilities for the purposes of this division. The thermal power plant does not include any wind, hydroelectric, or solar photovoltaic electrical generating facility.

Thermal Stratification:
The formation of layers of different temperatures in a lake or reservoir.

Thermal System Insulation (TSI):
Asbestos-containing material applied to pipes, fittings, boilers, breeching, tanks, ducts, or other interior structural components to prevent heat loss or gain or water condensation.

Thermal Treatment:
Use of elevated temperatures to treat hazardous wastes.

Thermally Enhanced Oil Recovery (TEOR):
Injection of steam to increase the amount of petroleum that may be recovered from a well.

The middle layer of a thermally stratified lake or reservoir. In this layer, there is a rapid decrease in temperatures in a lake or reservoir.

Thermodynamics: A study of the transformation of energy into other manifested forms and of their practical applications. The three laws of thermodynamics are:

1. Law of Conservation of Energy -- energy may be transformed in an isolated system, but its total is constant

2. Heat cannot be changed directly into work at constant temperature by a cyclic process

3. Heat capacity and entropy of every crystalline solid becomes zero at absolute zero (0 degrees Kelvin)

Thermostat: An automatic control device designed to be responsive to temperature and typically used to maintain set temperatures by cycling the HVAC system.

Thermostat, Setback:
A device, containing a clock mechanism, which can automatically change the inside temperature maintained by the HVAC system according to a preset schedule. The heating or cooling requirements can be reduced when a building is unoccupied or when occupants are asleep.

Threshold: The lowest dose of a chemical at which a specified measurable effect is observed and below which it is not observed.

Threshold: The dose or exposure level below which a significant adverse effect is not expected.

Threshold Level:
Time-weighted average pollutant concentration values, exposure beyond which is likely to adversely affect human health.

Threshold Limit Value (TLV):
The concentration of an airborne substance to which an average person can be repeatedly exposed without adverse effects. TLVs may be expressed in three ways: (1) TLV-TWA--Time-weighted average, based on an allowable exposure averaged over a normal 8-hour workday or 40-hour work- week; (2) TLV-STEL--Short-term exposure limit or maximum concentration for a brief specified period of time, depending on a specific chemical (TWA must still be met); and (3) TLV-C--Ceiling Exposure Limit or maximum exposure concentration not to be exceeded under any circumstances. (TWA must still be met.)

Threshold Planning Quantity: A quantity designated for each chemical on the list of extremely hazardous substances that triggers the notification by facilities to the State Emergency Response Commission that such facilities are subject to emergency planning requirements under SARA Title III.

Tropic Levels: A functional classification of species that is based on feeding relationships (e.g. generally aquatic and terrestrial green plants comprise the first tropic level, and herbivores comprise the second.)

Tidal Marsh: Low, flat marshlands traversed by channels and tidal hollows, subject to tidal inundation; normally, the only vegetation present is salt-tolerant bushes and grasses.

Tidal Power:
Energy obtained by using the motion of the tides to run water turbines that drive electric generators.

Tillage: Plowing, seedbed preparation, and cultivation practices.

Time-Of-Use Meter: A measuring device that records the times during which a customer uses various amounts of electricity. This type of meter is used for customers who pay time-of-use rates.

Time-Of-Use Rates: Electricity prices that vary depending on the time periods in which the energy is consumed. In a time-of- use rate structure, higher prices are charged during utility peak-load times. Such rates can provide an incentive for consumers to curb power use during peak times.

Time-Of-Use (TOU) Rates:
The pricing of electricity based on the estimated cost of electricity during a particular time block. Time-of-use rates are usually divided into three or four-time blocks per twenty-four hour period (on-peak, mid-peak, off-peak and sometimes super off-peak) and by seasons of the year (summer and winter). Real-time pricing differs from TOU rates in that it is based on actual (as opposed to forecasted) prices which may fluctuate many times a day and are weather-sensitive, rather than varying with a fixed schedule.

Time-weighted Average (TWA): In air sampling, the average air concentration of contaminants during a given period.

Tipping Fee:
A fee for unloading or dumping waste at a landfill, transfer station, waste-to-energy facility, or recycling facility (also see Disposal Fee).

Tipping Floor: Unloading area for vehicles that are delivering MSW to a waste-to-energy plant.

Tire Processor:
The intermediate operating facility where recovered tires are processed in preparation for recycling.

Tires: As used in recycling, passenger car and truck tires (excludes airplane, bus, motorcycle and special service military, agricultural, off-the-road and-slow speed industrial tires). Car and truck tires are recycled into rubber products such as trash cans, storage containers, rubberized asphalt or used whole for playground and reef construction.

Tolerance Petition:
A formal request to establish a new tolerance or modify an existing one.

Permissible residue levels for pesticides in raw agricultural produce and processed foods. Whenever a pesticide is registered for use on a food or a feed crop, a tolerance (or exemption from the tolerance requirement) must be established. EPA establishes the tolerance levels, which are enforced by the Food and Drug Administration and the Department of Agriculture.

Ton Of Cooling: A useful cooling effect equal to 12,000 Btu hours.

Tonnage: The amount of waste that a landfill accepts, usually expressed in tons per month. The rate at which a landfill accepts waste is limited by the landfill's permit.

The physical features of a surface area including relative elevations and the position of natural and man-made (anthropogenic) features.

Total Dissolved Phosphorous:
The total phosphorous content of all material that will pass through a filter, which is determined as orthophosphate without prior digestion or hydrolysis. Also called soluble P or ortho-P.

Total Dissolved Solids (TDS):
All material that passes the standard glass river filter; now called total filterable residue. The term is used to reflect salinity.

Total Efficiency:
Sum of the electrical and thermal efficiency in relation to the fuel consumed

Total Maximum Daily Load (TMDL):
A calculation of the highest amount of a pollutant that a water body can receive and safely meet water quality standards set by the state, territory, or authorized tribe.

Total Petroleum Hydrocarbons (TPH): Measure of the concentration or mass of petroleum hydrocarbon constituents present in a given amount of soil or water. The word "total" is a misnomer--few, if any, of the procedures for quantifying hydrocarbons, can measure all of them in a given sample. Volatile ones are usually lost in the process and not quantified and non-petroleum hydrocarbons sometimes appear in the analysis.

Total Recovered Petroleum Hydrocarbon:
A method for measuring petroleum hydrocarbons in samples of soil or water.

Total Suspended Particles (TSP):
A method of monitoring airborne particulate matter by total weight.

Total Suspended Solids (TSS):
A measure of the suspended solids in wastewater, effluent, or water bodies, determined by tests for "total suspended non-filterable solids".

Toxaphene: Chemical that causes adverse health effects in domestic water supplies and is toxic to fresh water and marine aquatic life.

Toxic Air Pollutant: Poisonous substances in the air that come from natural resources or manmade sources and can harm the environment or human health.

Toxic Chemical:
Any chemical listed in EPA rules as "Toxic Chemicals Subject to Section 313 of the Emergency Planning and Community Right-to-Know Act of 1986."

Toxic Chemical Release Form: Information form required of facilities that manufacture, process, or use (in quantities above a specific amount) chemicals listed under SARA Title III.

Toxic Chemical Use Substitution:
Replacing toxic chemicals with less harmful chemicals in industrial processes.

Toxic Cloud:
Airborne plume of gasses, vapors, fumes, or aerosols containing toxic materials.

Toxic Concentration:
The concentration at which a substance produces a toxic effect.

Toxic Dose: The dose level at which a substance produces a toxic effect.

Toxic Pollutants:
Materials that cause death, disease, or birth defects in organisms that ingest or absorb them. The quantities and exposures necessary to cause these effects can vary widely.

Toxic Release Inventory: Database of toxic releases in the United States compiled from SARA Title III Section 313 reports.

Toxic Substance: A chemical or mixture that may present an unreasonable risk of injury to health or the environment.

Toxic Waste: A waste that can produce injury if inhaled, swallowed, or absorbed through the skin.

A harmful substance or agent that may injure an exposed organism.

Toxicity: The degree to which a substance or mixture of substances can harm humans or animals. Acute toxicity involves harmful effects in an organism through a single or short-term exposure. Chronic toxicity is the ability of a substance or mixture of substances to cause harmful effects over an extended period, usually upon repeated or continuous exposure sometimes lasting for the entire life of the exposed organism. Subchronic toxicity is the ability of the substance to cause effects for more than one year but less than the lifetime of the exposed organism.

Toxicity Assessment: Characterization of the toxicological properties and effects of a chemical, with special emphasis on the establishment of dose-response characteristics.

Toxicity Testing: Biological testing (usually with an invertebrate, fish, or small mammal) to determine the adverse effects of a compound or effluent.

Toxicological Profile: An examination, summary, and interpretation of a hazardous substance to determine levels of exposure and associated health effects.

Trading Day: The 24-hour period beginning at midnight and ending at the following midnight.

Transboundary Pollutants: Air pollution that travels from one jurisdiction to another, often crossing state or international boundaries. Also, applies to water pollution.

Transfer: The act of moving waste from a collection vehicle to a larger transport vehicle.

Transfer (Electric Utility): To move electric energy from one utility system to another over transmission lines.

Transfer Point: A designated point, often at the edge of a neighborhood, where small collection vehicles transfer waste to larger vehicles for transport to disposal sites.

Transfer Station: Facility where solid waste is transferred from collection vehicles to larger trucks or rail cars for longer distance transport.

Transformer: A device, which through electromagnetic induction but without the use of moving parts, transforms alternating or intermittent electric energy in one circuit into energy of similar type in another circuit, commonly with altered values of voltage and current.

Transient Water System: A non-community water system that does not serve 25 of the same non-residents per day for more than six months per year.

Transition Costs:
See Embedded Costs Exceeding Market Prices.

Transitional Low Emission Vehicle (TLEV):
A vehicle certified by the California Air Resources Board to have emissions from zero to 50,000 miles no higher than 0.125 grams/mile (g/mi) of non-methane organic gasses, 3.4 g/mi of carbon monoxide, and 0.4 g/mi of nitrogen oxides. Emissions from 50,000 to 100,000 miles may be slightly higher.

Transmission: Transporting bulk power over long distances.

Transmission-Dependent Utility:
A utility that relies on its neighboring utilities to transmit to it the power it buys from its suppliers. A utility without its own generation sources, dependent on another utility's transmission system to get its purchased power supplies.

Transmission Lines: Pipelines that transport raw water from its source to a water treatment plant, then to the distribution grid system.

Transmission Owner:
An entity that owns transmission facilities or has the firm contractual right to use transmission facilities.

The ability of an aquifer to transmit water.

Transmittance: The time rate of heat flow per unit area under steady conditions from the air (or other fluid) on the warm side of a barrier to the air (or fluid) on the cool side, per unit temperature difference between the two sides.

Transmitting Utility (TRANSCO):
This is a regulated entity which owns and may construct and maintain, wires used to transmit wholesale power. It may or may not handle the power dispatch and coordination functions. It is regulated to provide non-discriminatory connections, comparable service, and cost recovery. According to EP Act, any electric utility, qualifying cogeneration facility, qualifying small power production facility, or Federal power marketing agency which owns or operates electric power transmission facilities which are used for the sale of electric energy at wholesale.

The process by which water vapor is lost to the atmosphere from living plants. The term can also be applied to the quantity of water thus dissipated.

Transportation Control Measures (TCMs):
Steps were taken by a locality to reduce vehicular emission and improve air quality by reducing or changing the flow of traffic; e.g. bus and HOV lanes, carpooling and other forms of ride-sharing, public transit, bicycle lanes.

Hauling firm that picks up properly packaged and labeled hazardous waste from generators and transports it to designated facilities for treatment, storage, or disposal. Transporters are subject to EPA and DOT hazardous waste regulations.

Trash: Material considered worthless or offensive that is thrown away. Generally defined as a dry waste material, but in common usage, it is a synonym for garbage, rubbish, or refuse.

Trash-to-Energy Plan: Burning trash to produce energy.

Treatability Studies:
Tests of potential cleanup technologies conducted in a laboratory.

Treated Regulated Medical Waste: Medical waste treated to substantially reduce or eliminate its pathogenicity, but that has not yet been destroyed.

Treated Wastewater:
Wastewater that has been subjected to one or more physical, chemical, and biological processes to reduce its potential of being a health hazard.

(1) Any method, technique, or process designed to remove solids and/or pollutants from solid waste, waste-streams, effluents, and air emissions. (2) Methods used to change the biological character or composition of any regulated medical waste so as to substantially reduce or eliminate its potential for causing disease.

Treatment Plant:
A structure built to treat wastewater before discharging it into the environment.

Treatment, Storage, and Disposal Facility:
Site where a hazardous substance is treated, stored, or disposed of. TSD facilities are regulated by EPA and states under RCRA.

Tremie: Device used to place concrete or grout under water.

Trial Burn: An incinerator test in which emissions are monitored for the presence of specific organic compounds, particulates, and hydrogen chloride.

Trichloroethylene (TCE):
A stable, low boiling-point colorless liquid, toxic if inhaled. Used as a solvent or metal degreasing agent, and in other industrial applications.

Trickle Irrigation:
Method in which water drips to the soil from perforated tubes or emitters.

Trickling Filter:
A coarse treatment system in which wastewater is trickled over a bed of stones or other material covered with bacteria that break down the organic waste and produce clean water.

Trihalomethane (THM):
One of a family of organic compounds named as derivative of methane. THMs are generally by-products of chlorination of drinking water that contains organic material.

The layer of the atmosphere closest to the earth's surface.

Truck Scales or Weighbridge: A platform used for weighing vehicles.

Trust Fund (CERCLA):
A fund set up under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) to help pay for the cleanup of hazardous waste sites and for legal action to force those responsible for the sites to clean them up.

Tube Settler:
Device using bundles of tubes to let solids in water settle to the bottom for removal by conventional sludge collection means; sometimes used in sedimentation basins and clarifiers to improve particle removal.

Tuberculation: Development or formation of small mounds of corrosion products on the inside of the iron pipe. These tubercules roughen the inside of the pipe, increasing its resistance to water flow.

Tundra: A type of treeless ecosystem dominated by lichens, mosses, grasses, and woody plants. Tundra is found at high latitudes (arctic tundra) and high altitudes (alpine tundra). Arctic tundra is underlain by permafrost and is usually water saturated.

Turbidimeter: A device that measures the cloudiness of suspended solids in a liquid; a measure of the quantity of suspended solids.

Turbidity: 1. Haziness in the air caused by the presence of particles and pollutants. 2. A cloudy condition in water due to suspended silt or organic matter.

Turbine Generator:
A device that uses steam, heated gasses, water flow or the wind to cause spinning motion that activates electromagnetic forces and generates electricity.

UA: A measure of the amount of heat that would be transferred to a given surface or enclosure (such as a building envelope) with a one degree Fahrenheit temperature difference between the two sides. The UA is calculated by multiplying the U-Value by the area of the surface (or surfaces).

Utility distribution company. An entity that owns a distribution system for the delivery of energy to and from the ISO-controlled grid and that provides regulated, retail service to eligible end-use customers who are not yet eligible for direct access, or who choose not to arrange services through another retailer.

Ultra-Low Emission Vehicle ( ULEV):
A vehicle certified by the California Air Resources Board to have emissions from zero to 50,000 miles no higher than 0.040 grams/mile (g/mi) of non-methane organic gasses, 1.7 g/mi of carbon monoxide, and 0.2 g/mi of nitrogen oxides. Emissions from 50,000 to 100,000 miles may be slightly higher.

Ultrahigh Voltage Transmission:
Transporting electricity over bulk-power lines at voltages greater than 800 kilovolts.

Unbundling: Disaggregating electric utility service into its basic components and offering each component separately for sale with separate rates for each component. For example, generation, transmission, and distribution could be unbundled and offered as discrete services.

Universal Hazardous Waste (UHW): Certain hazardous, widely generate materials such as batteries, pesticides, and thermostats.

Universal Service:
Electric service sufficient for basic needs (an evolving bundle of basic services) available to virtually all members of the population regardless of income.

Unleaded Gasoline: Gasoline that has had tetraethyl lead removed in conformance with federal and state regulations.

Upcycling: The process of recycling in such a way that new products are of higher economic value.

Upgrade (Electric Utility):
Replacement or addition of electrical equipment resulting in increased generation or transmission capability.

Uprate (Electric Utility):
An increase in the rating or stated measure of generation or transfer capability.

Upstream: A term used in the petroleum industry referring to the exploration and production side of the business. This includes pipelines but production before reaching the refinery.

Uranium: A radioactive element, found in ores, of which atoms can be split to create energy.

Uranium Enrichment: The process of increasing the percentage of pure uranium above the levels found in naturally occurring uranium ore, so that it may be used as fuel.

A regulated entity which exhibits the characteristics of a natural monopoly. For the purposes of electric industry restructuring, "utility" refers to the regulated, vertically-integrated electric company. "Transmission utility" refers to the regulated owner/operator of the transmission system only. "Distribution utility" refers to the regulated owner/operator of the distribution system which serves retail customers.

Variable Air Volume System (VAV System): A mechanical HVAC system capable of serving multiple zones which control the temperature maintained in a zone by controlling the amount of heated or cooled air supplied to the zone.

Vectors: Organisms that carry disease-causing pathogens. At landfills rodents, flies, and birds are the main vectors that spread pathogens beyond the landfill site.

Ventilation: The process of supplying or removing air by natural or mechanical means to or from any space. Such air may or may not have been conditioned or treated.

Vertical Integration:
An arrangement whereby the same company owns all the different aspects of making, selling, and delivering a product or service. In the electric industry, it refers to the historically common arrangement whereby a utility would own its own generating plants, transmission system, and distribution lines to provide all aspects of electric service.

Virgin Materials: Any basic material for industrial processes that has not previously been used, for example, wood-pulp trees, iron ore, crude oil, bauxite.

Visible Light Transmittance:
The ratio of visible light transmitted through a substance to the total visible light incident on its surface.

Volatile Organic Compounds (VOCs):
Compounds that evaporate from many housekeeping, maintenance and building products made with organic chemicals. These compounds may be released from the products both in use and in storage. In sufficient quantities, VOCs can cause irritation and some are carcinogenic and are suspected of causing or exacerbating acute and chronic diseases. The health effects of VOCs at levels found typically in commercial indoor environments are still not completely known and continue to be a point for further study.

Volt: A unit of electromotive force. It is the amount of force required to drive a steady current of one ampere through a resistance of one ohm. Electrical systems of most homes and office have 120 volts.

Hard to describe, but just as it takes pressure to move water through a pipe, it takes voltage to move electricity across a wire. Transmission lines usually carry power at 500, 230 or 115 kV. It is “stepped down” into a lower voltage (69 kV and lower) by transformers at substations and along distribution lines for final delivery to homes and businesses. It comes into your house at 220 volts, and most of your household plugs carry 110 volts.

Voltage Of A Circuit (Electric Utility):
The electric pressure of a circuit, measured in volts. Usually a nominal rating, based on the maximum normal effective difference of potential between any two conductors of the circuit.

Volumetric Wires Charge:
A type of charge for using the transmission and/or distribution system that is based on the volume of electricity that is transmitted.

Warranty: A seller's guarantee to purchaser that product is what it is represented to be and, if it is not, that it will be repaired or replaced. Within the context of vehicles, refers to an engine manufacturer's guarantee that the engine will meet "certified" engine standards at 50,000 miles or the engine will be replaced. Retrofits may generally void an engine warranty.

Waste-based Energy (WBE):
The process of extracting useful energy from a waste stream

Waste Characterization Study:
An analysis of samples from a waste stream to determine its composition.

Waste Collection:
All the operations involved in collecting waste and channelling it to a transfer or sorting center, incineration plant or landfill.

Waste collector: a person employed by a local authority or a private firm to collect waste from residences, businesses, and community bins.

Waste Dealer: A middleman who buys recyclable materials from waste generators and itinerant buyers and sells them, after sorting and some processing, to wholesale brokers or recycling industries.

Waste Management Hierarchy:
A ranking of waste management operations according to their environmental or energy benefits. The purpose of the waste management hierarchy is to make waste management practices as environmentally sound as possible.

Waste Picker: A person who picks out recyclables from mixed waste wherever it may be temporarily accessible or disposed of.

Waste Prevention: A change in the design, manufacturing, purchase or use of materials or products (including packaging) to reduce their amount of toxicity before they are discarded. Waste prevention also refers to the reuse of products or materials.

Waste Reduction:
All means of reducing the amount of waste that is produced initially and that must be collected by solid waste authorities. This ranges from legislation and product design to local programs designed to keep recyclables and compostables out of the final waste stream.

Waste Residue:
The portion of the waste stream (domestic and commercial) which cannot currently be recovered or recycled

Waste Stream: Specific types of waste found in customer's disposal (trash, cardboard, aluminum and metal) or a more broad definition of disposal type. (e.g. MSW, C&D, Hazardous, etc.).The total flow of waste from a community, region, or facility.

Burning of waste to generate steam, heat or electricity.

Waste-to-Energy (WTE) Plant:
A facility that generates steam and/or electricity through the combustion of municipal solid waste. These facilities consist of large incinerator-type operations where trash is incinerated (burned). The heat from this combustion process is converted into high-pressure steam, which can be used to generate electricity for sale to public utility companies under long-term contracts. The residue from the incineration process is disposed of in a Landfill.

Wastewater: Water carrying dissolved or suspended solids from homes, farms, businesses and industries.

Water Heater: An appliance for supplying hot water for purposes other than space heating or pool heating.

Water Table: Level below the earth's surface at which the ground becomes saturated with water.

WATSCO: The Western Association for Transmission System Coordination.

Watt: A unit of measure of electric power at a point in time, as capacity or demand.

Watt: A measure of electricity. If you have 10, 100-watt bulbs all on at the same time, the “demand” or instantaneous measure of the power required for the job, is 1,000 watts, also called 1 kilowatt, or kW. If you keep them lit for one full hour, you have used 1,000 watt-hours of electricity, also called a kilowatt-hour or kWh. The typical American home uses about 840 kWh per month.

One watt of power expended for one hour.

Specially designed strips, seals, and gaskets installed around doors and windows to limit air leakage.

Wet-Bulb Temperature:
The temperature at which water, by evaporating into the air, can bring the air to saturation at the same temperature. Wet-bulb temperature is measured by a wet-bulb psychrometer.

An area that is regularly wet or flooded and has a water table that stands at or above the land surface for at least part of the year.

Wheelabrator (WTI): The WMI waste-to-energy facilities are part of Wheelabrator Technologies, Inc. These facilities consist of large incinerator-type operations where trash is incinerated (burned). The heat from this combustion process is converted into high-pressure steam, which can be used to generate electricity for sale to public utility companies under long-term contracts. The residue from the incineration process is disposed of in a Landfill.

The transmission of electricity by an entity that does not own or directly uses the power it is transmitting. Wholesale wheeling is used to indicate bulk transactions in the wholesale market, whereas retail wheeling allows power producers direct access to retail customers. This term is often used colloquially as meaning transmission.

Whole House Fan:
A system capable of cooling a house by exhausting a large volume of warm air when the outside air is cool.

Wholesale Competition:
A system whereby a distributor of power would have the option to buy its power from a variety of power producers, and the power producers would be able to compete to sell their power to a variety of distribution companies.

Wholesale Power Market:
The purchase and sale of electricity from generators to resellers (who sell to retail customers) along with the ancillary services needed to maintain reliability and power quality at the transmission level.

Wholesale Transmission Services:
The transmission of electric energy sold, or to be sold, at wholesale in interstate commerce (from EP Act).

An elongated pile of aerobically composting materials that are turned periodically to expose the materials to oxygen and to control the temperature to promote biodegradation.

Wires Charge: A broad term which refers to charges levied on power suppliers or their customers for the use of the transmission or distribution wires.

Wobbe Index:
A measure of the amount of heat released by a gas burner with a constant orifice, equal to the gross calorific value of the gas in British thermal units per cubic foot at standard temperature and pressure divided by the square root of the specific gravity of the gas. The index is an indicator of the quality of the fuel gas.

Working Face :
The length and width of the row in which waste is being deposited at a landfill. Also known as the tipping face.

Worin Castings: The material produced from the digestive tracts of worms as they live in earth or compost piles. The castings are rich in nitrates, potassium, phosphorous, calcium, and magnesium.

Worm Culture:
A relatively cool, aerobic composting process that uses worms and microorganisms; also known as viniculture.

X-Ray: A type of electromagnetic radiation having low energy levels.

A heavy gas used in specialized electric lamps.

Xyloid Coal: Brown coal or lignite mostly derived from wood.

Yard Waste: Leaves, grass clippings, prunings, and other natural organic matter discarded from yards and gardens