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Gallon: A unit of volume. A U.S. gallon has 231 cubic inches or 3.785 litres.

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 at 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 buildup of carbon dioxide and other greenhouse gases 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 gases. 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 gases 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 gases 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 release of airborne fibres 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 vapour, carbon dioxide and other gases 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 gases are gases that absorb a portion of the sun's rays, such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), CFCs and HCFCs; synthetic gases 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 gases make the earth warmer than would direct sunlight alone. These gases (carbon dioxide [CO2], methane [CH4], nitrous oxide [N2O], tropospheric ozone [O3], and water vapour [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 gases 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). 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 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 centimetres (a foot). Generally, ditches deep enough to cross with farm equipment are considered gullies.