Abatement: Abatement is the reduction in the quantity of intensity of greenhouse gas emissions and removal of a waste stream which is located in any given area.

Activated Carbon Filter: Water treatment process to remove taste, odor, some organic compounds, and radon.

Adsorption: retention of a substance by soil particles.

Aerobic: in the presence of or requiring oxygen.

Aerobic composting: a method of com-posting organic wastes using bacteria that need oxygen. This requires that the waste be exposed to air, either via turning or by forcing air through pipes that pass through the material.

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

Agri-chemical: chemicals (fertilizers and pesticides) used in agricultural production.

Algal Bloom: large, visible masses of algae found in bodies of water during warm water.

Alkalinity: capacity of water to neutralize acids by its content of bicarbonates, carbonates, or hydroxides.

Ambient Monitoring: performed to determine existing environmental conditions or contaminant levels in the environment, against which future conditions can be compared.

Anaerobic (Anoxic): in the absence of oxygen.

Anaerobic digestion: a method of composting that does not require oxygen. This composting method produces methane. Also known as anaerobic composting.

Aquifer: water-bearing formation of rock or soil that will yield useable supplies of water. May be classified as confined or unconfined.

Ash: the noncombustible solid by-products of incineration or other burning process.

Assimilative Capacity: natural ability of soil and water to use and decompose potential pollutants without harmful effects to the environment.

Available Nitrogen: amount of nitrogen present as either nitrate or ammonium, forms which can be readily taken up by plants.

Available Water: the portion of water in soil that can be readily absorbed by plant roots.

Background Level: amount of a substance which occurs naturally in the environment.

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

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.

Bacteria: microscopic one-celled organisms which live everywhere and perform a variety of functions. While decomposing organic matter in water, bacteria can greatly reduce the amount of oxygen in the water.

Baler: machine used to compress and bind recyclables, such as aluminum, paper, corrugated cardboard and plastics.

Bentonite: highly plastic clay consisting of the minerals montmorillonite and beidellite that swells when wet and is often used as a lining material to seal landfills and lagoons.

Best Management Practice (BMP): structural or managerial technique recognized as the most effective and practical means of controlling pollution for an agricultural, urban, forested, or mining area.

Biochemical Oxygen Demand (BOD): laboratory measurement of the amount of oxygen consumed by microorganisms while decomposing organic matter in a product. BOD levels are indicative of the effect of the waste on fish or other aquatic life which require oxygen to live, and though not a specific compound, it is defined as a conventional pollutant under the federal Clean Water Act.

Biodegradable material: any organic material that can be broken down by microorganisms into simpler, more stable com-pounds. Most organic wastes (e.g., food, paper) are biodegradable.

Black Water: liquid and solid human body waste and the carriage water generated by toilet use.

Bottle Bill: law requiring deposits on beverage containers (see Container Deposit Legislation).

Bottom ash: relatively coarse, noncombustible, generally toxic residue of incineration that accumulates on the grate of a furnace.

BTX: a test for benzene, toluene, and xylene, three organic compounds characteristically present in gasoline.

Buffer Zone: neutral area which acts as a protective barrier separating two conflicting forces. An area which acts to minimize the impact of pollutants on the environment or public welfare. For example, a buffer zone is established between a compositing facility and neighboring residents to minimize odor problems.

Bulky Waste: large items of refuse including, but not limited to, appliances, furniture, large auto parts, non-hazardous construction and demolition material, trees, branches and stumps which cannot be handled by normal solid waste processing, collection and disposal methods.

Buy-Back Center: facility where individuals bring recyclables in exchange for payment.

Carcinogen: substance which causes cancer.

Cell: the basic unit by which a landfill is developed. It is the general area where incoming waste is tipped, spread, compacted, and covered.

Chemical Oxygen Demand (COD): laboratory measurement of the amount of oxygen used in chemical reactions that occur in water as a result of the addition of wastes. A major objective of conventional wastewater treatment is to reduce the chemical and biochemical oxygen demand.

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

Chlorination: addition of chlorine as a means of disinfecting drinking water or wastewater.

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

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

Cogeneration: production of both electricity and steam from one facility, from the same fuel source.

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.

Co-compositing: simultaneous composting of two or more diverse waste streams.

Coliform Bacteria: microorganisms which typically inhabit the intestines of warm-blooded animals. They are commonly measured in drinking water analyses to indicate pollution by human or animal waste.

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

Combustion: in MSW, the burning of materials in an incinerator.

Commercial Waste: materials originating in wholesale, retail, institutional or service establishments such as offices, stores, markets, theaters, hotels and warehouses.

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

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

Compactor: power-driven device used to compress materials to smaller volume.

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

Compost: the material resulting from com posting. Compost, also called humus, is a soil conditioner and in some instances is used as a fertilizer.

Composting: controlled microbial degradation of organic waste yielding an environmentally sound product with value as a soil amendment. It is also the biological decomposition of solid organic materials by bacteria, fungi, and other organisms into a soil-like product.

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

Comprehensive Environmental Response, Compensation and Liability Act (CERCLA): See Superfund.

Confined Aquifer: water-bearing formation whose upper boundary is a layer which does not transmit water readily.

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.

Controlled dump: a planned landfill that incorporates to some extent some of the features of a sanitary landfill: siting with respect to hydrogeological 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.

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

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

Contaminant: any physical, chemical, biological, or radiological substance causing an impurity in the environment.

Corrosive: capable of eating away materials and destroying living tissue on contact.

Corrugated: structural paper or cardboard shaped in parallel furrows and ridges for rigidity.

Curbside Collection: program where recyclable materials are collected at the curb, often from special containers, to be taken to various processing facilities.

Deactivation: process in which a pesticide adheres to a soil particle or some organic material so tightly that it is no longer biologically available.

Decomposition: breaking down into component parts or basic elements.

Decomposition Gases: produced in the breakdown of garbage or other material. Some, such as methane, are flammable.

Degradable: capable of being chemically reduced or broken down.

Denitrification: biochemical conversion of nitrate (NO3) to nitrite (NO2), ammonia (NH3), and free nitrogen (N), as in soil by microorganisms.

Dioxins: heterocyclic hydrocarbons that occur as toxic impurities, especially in pesticides.

Discharge: flow of surface water in a stream or the flow of ground water from a spring, ditch, or flowing artesion well.

Disposal: the final handling of solid waste, following collection, processing, or incineration. Disposal most often means placement of wastes in a dump or a landfill.

Disposable: manufactured to be used for a short time and then thrown away; not durable or repairable.

Dissolved Oxygen (DO): oxygen dissolved in water and readily available to fish and other aquatic organisms.

Diversion Rate: measure of the amount of waste material being diverted for recycling compared with the total amount previously thrown away.

Drawdown: vertical drop of the water level in a well during pumping.

Drop-off Center: method of collecting recyclable or compostible materials in which materials are taken by individuals to collection sites and deposited into designated containers.

Dump: see controlled dump and open dump.

Eco-efficiency: This means achieving the environmental and economic balance in recycling. It entails maximizing both the physical recycling of metals (or other materials) and the revenue obtained, while minimizing the associated environmental burden and total cost. An eco-efficient process also considers the "environmental fingerprint" of materials, i.e. how much negative environmental impact can be saved by recycling, for example, a metal, instead of producing it "new" by mining. Due to the considerable (environmental) impact of turning precious metals from low grade ores into pure metals, a high overall recycling yield of them has not merely economic benefits, but also substantial ecological advantages (recycling 1 kg of gold is much more beneficial, both financially and ecologically, than recycling 1 kg of iron). In a purely weight-based calculation of recycling-rates, this effect is not considered properly.

Ecosystem: community of animals and plants and the physical environment in which they live.

Effluent: discharge or emission of a liquid or gas. Emissions: gases released into the atmosphere.

Energy Recovery: conversion of waste energy, generally through the combustion of processed or raw refuse (incineration), to produce steam typically from the heat produced by incineration or via methane gas from landfills.

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 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.

Erosion: natural breakdown and movement of soil and rock by water, wind, or ice. The process may be accelerated by human activities.

Escherichia coli (E. coli): species of coliform bacteria that inhabit intestines of people and animals.

Eutrophication: degradation of water quality due enrichment by nutrients, primarily nitrogen (N) and phosphorus (P), which results in excessive plant (principally algae) growth and decay. Low dissolved oxygen (DO) in the water is a common consequence.

Evapotranspiration (ET): loss of water to the atmosphere from the earth's surface by evaporation and by transpiration through plants.

Explosive / Reactive: capable of causing an explosion or releasing poisonous fumes when exposed to air, water, or other chemicals.

Fabric filter: see baghouse.

Flaring: the burning of methane emitted from collection pipes at a landfill.

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 cause the bed to bubble, which gives rise to the term fluidized.

Fly ash: the highly toxic particulate matter captured from the flue gas of an incinerator by the air pollution control system.

Formulation: the combination of active and inactive (inert) ingredients which make up a pesticide.

Fumigant: gaseous material used to destroy insects, pathogens, or other pests in soil or grain bins.

Fungicide: substance that kills fungi.

Garbage: waste food that is thrown away, generally defined as wet food waste. The term is also used to describe all products discarded, regardless of their reusability or recyclability. Geographic Information System: computerized database system containing natural resources and land use data that can be used to analyze and display information in spatial, or map, format.

Giardiasis: presence of the Giardia lamblia protozoan in the human small intestine which can cause diarrhea.

Grey Water: wastewater other than sewage, such as sink or washing machine drainage.

Ground Water: water in the saturated zone (below the water table).

Half-life: time required for one-half of a specified substance to decompose.

Hammermill: type of crusher or shredder used to break up waste materials into smaller pieces.

Hardness: characteristic of water which describes the presence of dissolved minerals. Carbonate hardness is caused by calcium and magnesium bicarbonate; noncarbonate hardness is caused by calcium sulfate, calcium chloride, magnesium sulfate, and magnesium chloride.

Hazardous Waste: solid, liquid, or gaseous substance which, because of its source or measurable characteristics, is classified under state or federal law as potentially dangerous and is subject to special handling, shipping, and disposal requirements.

Head: the height of a column of water above a standard datum such as mean sea level.

Health Advisory (HA): non-regulatory, health-based reference level of drinking water contaminants at which adverse health effects are believed to be minimal. HA levels are established for 1-day, 10-day, longer-term, and lifetime exposure periods, and they include large safety margins.

Heavy Metals: those metals (elements with high density, malleability, and electrical and thermal conductivity) that have high specific gravity and high atomic mass, such as lead, cadmium, zinc, copper, silver, and mercury. These may be found in the waste stream as part of discarded items such as batteries, lighting fixtures, colorants and inks.

Herbicide: chemical used to destroy or inhibit undesirable plant growth. High Grade Paper: relatively valuable paper such as computer printout, white ledger, and tab cards. Also used to refer to industrial trimmings at paper mills that are recycled.

Household Hazardous Waste: discarded or usused portions of home cleaning products, workshop and outdoor chemicals, automotive fluids, and personal care products that contain toxic chemicals. Products labeled WARNING, CAUTION, POISONOUS, TOXIC, FLAMMABLE, REACTIVE, or EXPLOSIVE are considered hazardous.

Humus: organic materials resulting from decay or plant or animal matter. Also referred to as compost.

Hydrologic Cycle: the movement of water in and on the earth and atmosphere through processes such as precipitation, evaporation, runoff, and infiltration.Hydrology: science dealing with the properties, distribution, and flow of water on or in the earth.

Hydrolysis: reaction of a water molecule with another larger molecule, resulting in the splitting of the larger molecule.

Ignitable: capable of burning or causing a fire.

Incineration: the process of burning solid waste under controlled conditions to reduce its weight and volume, and often to produce energy.

Incinerator: facility in which the combustion of solid waste takes place.

Industrial Waste: materials discarded from industrial operations or derived from manufacturing processes.

Infiltration: entry of water from precipitation, irrigation, or runoff into the soil profile.

Informal sector: the part of an economy that is characterized by private, usually small-scale, labor-intensive, largely unregulated, and unregistered manufacturing or provision of services.

Inorganic Chemicals: natural or synthetic chemicals that contain no carbon. Inorganic waste: waste composed of material other than plant or animal matter, such as sand, dust, glass, and many synthetics.

Insecticide: substance that kills insects.

Institutional Waste: material originating in schools, hospitals, prisons, research institutions, and other public buildings.

Integrated Solid Waste Management: practice of using several alternative waste management techniques to manage and dispose of specific components of the municipal waste stream. Waste management alternatives include source reduction, recycling, composting, energy recovery, and landfilling.

Intermediate Processing Center (IPC): type of materials recovery facility (MRF) that processes residentially collected mixed recyclables into new products available for market; often used interchangeably with MRF.

International NGO: an organization that has an international headquarters and branches in major world regions, often with the purpose of undertaking development assistance.

Itinerant waste buyer: a person who moves around the streets buying (or bartering for) reusable and recyclable materials.

In-vessel Composting: method in which the compost material is continuously and mechanically mixed and aerated in a large, contained area.

Landfill: see Sanitary Landfill.

Landfill gases: gases arising from the decomposition of organic wastes; principally methane, carbon dioxide, and hydrogen sulfide. Such gases may cause explosions at landfills.

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.

Lift: the completed layer of compacted waste in a cell at a landfill.

Liner: a protective layer, made of soil and/or synthetic materials, installed along the bottom and sides of a landfill to prevent or reduce the flow of leachate into the environment.

Leachate: liquid (which may be partly produced by 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 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: movement through soil of dissolved or suspended substances in water.

Lethal Dose (LD): amount of a substance required to cause death in an organism.

Loading: amount of a substance entering the environment (soil, water, or air).

Manual Separation: sorting of recyclables or compositable materials from waste by hand sorting.

Market waste: primarily organic waste, such as leaves, skins, and unsold food, discarded at or near food markets.

Mass Burn: municipal waste combustion technology in which solid waste is burned in a controlled system without prior sorting or processing.

Manual landfill: a landfill in which most operations are carried out without the use of mechanized equipment.

Materials Market: combination of manufacturing interests which buy recyclable materials and process them for reuse. The demand for goods made of recycled materials determines the economic feasibility of recycling and resource recovery.

Materials recovery: obtaining materials that can be reused or recycled.

Materials recovery facility (MRF): a facility for separating commingled recyclables by manual or mechanical means. Some MRFs are designed to separate recyclables from mixed MSW. MRFs then bale and market the recovered materials for sale to an end user.

Maximum Contaminant Level (MCL): enforceable EPA standard for the maximum permissible concentration of a contaminant in public water supplies. An MCL is set after considering health effects as well as the feasibility and cost of analysis and treatment of the regulated contaminant.

Maximum Contaminant Level Goal (MCLG): preliminary standard based entirely on health effects which is used by EPA to establish the MCL for a contaminant. For a chemical believed to cause cancer, the MCLG is zero.

Mechanical Separation: sorting of waste into various components using mechanical means, such as cyclones, trommels, and screens.

Metabolites: breakdown chemical products resulting when a pesticide passes through a biological system.

Methane: odorless, colorless, flammable and explosive gas produced by municipal solid waste undergoing anaerobic decomposition. Methane is emitted from municipal solid waste landfills.

Microenterprise: a synonym for small-scale enterprise: a business, often family-based or a cooperative, that usually employs fewer than ten people and may operate "informally."

Mineral Water: contains large amounts of dissolved minerals such as calcium, sodium, magnesium, and iron. Some tap waters contain as many or more minerals than some commercial mineral waters. There is no scientific evidence that either high or low mineral content water is beneficial to humans.

Mineralization: microbial conversion of an element from an organic (containing carbon) to an inorganic (not containing carbon) state.

Mixed waste: unsorted materials that have been discarded into the waste stream.

Modular Incinerator: small-scale waste combustion units prefabricated at a manufacturing facility and transported to the MWC facility site.

Monofill: a landfill intended for one type of waste only

Most Probable Number (MPN): statistical expression for estimating the number of microorganisms in a culture or a volume of water.

Mulch: natural or artificial layer of plant residue pr pther material covering the land surface which conserves soil moisture, holds soil in place, aids in establishing plant cover, and minimizes temperature fluctuations.

Municipal Solid Waste (MSW): all solid waste generated in an area except industrial and agricultural wastes. Sometimes includes construction and demolition debris and other special wastes that may enter the municipal waste stream. Generally excludes hazardous wastes except to the extent that they enter the municipal waste stream. Sometimes defined to mean all solid wastes that a city authority accepts responsibility for managing in some way. Non-hazardous discarded material generated in residential, commercial, institutional, and light industrial settings. It is defined by local governments, and in general does not include automobile oil, tires, lead-acid batteries, hazardous or infectious wastes, demolition debris, etc.

Municipal solid waste management: planning and implementation of systems to handle MSW.

NIMBY: acronym for "Not In My Back Yard" which is an expression of resident opposition to the siting of a solid waste facility based on the particular location proposed.

NGO: Nongovernmental organization. May be used to refer to a range of organizations from small community groups, through national organizations, to international ones. Frequently these are not-for-profit organizations.

Nitrification: biochemical oxidation of ammonia (NH3), ammonium (NH4), or atmospheric nitrogen (N) to nitrate (NO3) or nitrite (NO2).

Night soil: human excreta.

No Observeable Adverse Effect Level (NOAEL): chemical exposure dose or level producing no observeable adverse effect in long-term toxicity studies. This level is used to establish a tolerance for human consumption.

Nondischarge Systems: wastewater disposal systems that do not discharge to surface waters, such as spray irrigation, land application, or conventional septic systems.

Nonpoint Source (NPS) Contamination: water contamination derived from diffuse sources such as construction sites, agricultural fields, and urban runoff.

Nuisance Contaminant: constituents in water which are not normally harmful to health but may cause offensive taste, odor, color, corrosion, foaming, or staining.

Nutrient: element essential for plant or animal growth. Major nutrients include nitrogen, phosphorus, carbon, oxygen, sulfur, and potassium.

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.

Organic Compound: any carbon-based substance, including some petroleum products, solvents, pesticides, and halomethanes. Volatile organic compounds (VOCs) are those which are readily vaporized; a number of these are known or probable carcinogens.

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 material that is more directly derived from plant or animal sources, and which can generally be decomposed by microorganisms.

Oxygen Demand: materials such as food waste and dead plant or animal tissue that use up dissolved oxygen in the water when they are degraded through chemical or biological processes. Chemical and biochemical oxygen demand (COD and BOD) are measures of the amount of oxygen consumed when a substance degrades.

Package Treatment Plant: prefabricated, small-scale wastewater treatment system used in subdivisions or trailer parks.

Pathogen: disease-causing biological agent such as a bacterium, virus, or fungus.

Percolation: movement of water through soil or rock.

Permeability: capacity of soil, sediment, or porous rock to transmit water.

Persistence: resistance to degradation as measured by the period of time required for complete breakdown of a material. Depends on temperature, pH, soil type, light intensity, etc.

Pesticide: substance used for controlling, destroying, or repelling a specific pest. Includes fungicides, herbicides, insecticides, nematicides, rodenticides, defoliants, and plant growth regulators.

Photodegradeable: capable of being broken down (decomposed) by a chemical reaction initiated by direct exposure to the sun's ultraviolet radiation.

pH: numerical measure of acidity, with a scale of 0 to 14. Neutral is pH 7, values below 7 are acidic, and values above 7 are alkaline.

Picker: see waste picker.

Point-of-entry(POE): water treatment system located at the entry point to the home which treats all water used in the home.

Point-of-use: water treatment system located at the tap which treats only water used from the tap.

Point Source Contamination: water contamination from specific sources such as leaking underground storage tanks, landfills, industrial waste discharge points, or chemical mixing sites.

Pollution: the contamination of soil, water, or the atmosphere by the discharge of waste or other offensive materials. The presence of a contaminant to such a degree that the environment (land, water, or air) is not suitable for a particular use.

Polychlorinated Byphenyl (PCB): hazardous compound (suspected carcinogen) used for electrical insulation and heating/cooling equipment which has been found in air, soil, water, and fish across the country.

Polyethylene Terephthalate (PET): recyclable plastic used to make bottles such as soda bottles. Recycled PET is used in car bumpers, furniture, skis, surfboards, carpet yarn, polyester fiber, films and sheets, and molded parts.

Polyvinyl Chloride (PVC): common plastic material which releases hydrochloric acid when burned.

Post-Consumer Recycling: reuse of materials generated from residential and commercial waste; excludes recycling of material from industrial processes that has not reached the consumer, such as glass broken in the manufacturing process.

Post-Consumer Waste: material discarded by a business or residence that has fulfilled its useful life.

Potable: suitable for drinking.

Primary Drinking Water Standards: enforceable EPA standards which establish MCLs for drinking water contaminants after considering health effects and the feasibility and cost of analysis and treatment of regulated contaminants.

Primary material: a commercial material produced from virgin materials used for manufacturing basic products. Examples include wood pulp, iron ore, and silica sand.

Privatization: a general term referring to a range of contracts and other agreements that transfer the provision of some services or production from the public sector to private firms or organizations.

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.

Publicly Owned Treatment Works (POTW): wastewater treatment facility supported by public funding.

Putrescible: subject to decomposition or decay. Usually used in reference to food wastes and other organic wastes that decay quickly.

Pyrolysis: chemical decomposition of a substance by heat in the absence of oxygen, resulting in various hydrocarbon gases and carbon-like residue.

Radon: colorless, odorless, tasteless, radioactive gas.

Receiving Waters: bodies of water that receive runoff or wastewater discharges, such as rivers, streams, lakes, estuaries, and ground water.

Recharge: downward movement of water through soil to ground water.

Recharge Area: land area over which precipitation infiltrates into soil and percolates downward to replenish an aquifer.

Recyclables: materials that still have useful physical or chemical properties after serving their original purpose and that can be reused or remanufactured into additional products, thereby serving as substitutes for raw materials. Common examples are paper, glass, aluminum, corrugated cardboard and plastic containers.

Recycling: process by which materials otherwise destined for disposal are collected, reprocessed or remanufactured, and reused. Mandatory recycling programs require by law that consumers separate trash so that some or all recyclable materials are not burned or dumped in landfills.

Refractory: material able to withstand dramatic heat variations which may be used to construct conventional combustion chambers in incinerators.

Refuse Derived Fuel (RDF): fuel produced from MSW that has undergone processing. Processing can include separation of recyclables and noncombustible materials, shredding, size reduction, and pelletizing. A Product of a mixed waste processing system in which certain recyclable and non-combustible materials are removed, and the remaining combustible material is converted for use as a fuel to create energy. Densified Refuse Derived Fuel (d-RDF) results when the fuel is processed to form briquettes, pellets, or cubes. A term often used interchangeably with solid waste.

Residential Waste: materials generated in single and multiple-family homes.

Residue: materials remaining after processing, incineration, composting, or recycling have been completed; normally disposed of in landfills.

Resource Conservation and Recovery Act (RCRA): federal legislation related to hazardous waste (Subtitle C), solid, non-hazardous waste (Subtitle D), and the recovery and use of recycled materials and energy (Subtitle F).

Resource Recovery: extraction and utilization of materials and energy from the waste stream.

Reuse: use of a product, such as a soft drink bottle, in its original form more than once for the same purpose or a new purpose

Reverse Osmosis (RO): water treatment process in which contaminants are removed by forcing water through a membrane having microscopic holes that allow water molecules, but not larger compounds, to pass through. RO units do not remove all chemicals, and they generally discharge more than half of the total water as waste.

Roll-off Container: large waste container that fits onto a tractor trailer and can be loaded and unloaded hydraulically.

Rubbish: a general term for solid waste. Sometimes used to exclude food wastes and ashes.

Runoff: the portion of precipitation, snow melt, or irrigation which flows over and through soil, eventually reaching surface water (streams, rivers, lakes).

Safe Drinking Water Act(SDWA): passed by Congress in 1974, and amended in 1986, to insure safe drinking water. It directs the EPA to establish and enforce water quality standards to protect public health.

Sanitary Landfill: solid waste disposal site where waste is spread in layers, compacted, and covered with soil or other cover materials each day to minimize pest, aesthetic, disease, air pollution, and water pollution problems. Modern sanitary landfills are equipped with leachate collection and monitoring systems and methane gas controls and are operated in accordance with environmental protection standards.

Salinity: quality of water based on its salt content; seawater contains approximately 18,000 parts per million of salt.

Saturated Zone: portion of the soil or rock profile in which all pores are filled with water.

Secondary Drinking Water Standards: EPA guidelines for establishing Secondary Maximum Contaminant Levels (SMCLs), non-enforceable standards for nuisance contaminants that causes offensive taste, odor, color, corrosion, foaming, and staining.

Secondary material: a material recovered from post-consumer wastes for use in place of a primary material in manufacturing a product.

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.

Sediment: eroded soil and rock material, and plant debris, transported and deposited by water.

Septage: sludge removed from a septic tank (a chamber that holds human excreta).

Septic Tank: sewage disposal tank in which a continuous flow of waste material is decomposed by anaerobic (in the absence of oxygen) bacteria.

Set-out container: a box or bucket used for residential waste that is placed outside for collection.

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.

Site remediation: treatment of a contaminated site by removing contaminated solids or liquids or treating them on-site.

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.

Scavenger: one who illegally removes materials at any point in the solid waste management system.

Scrap: discarded or rejected industrial waste material often suitable for recycling.

Scrubber: anti-pollution device that uses a liquid or slurry spray to remove acid gases and particulates from municipal waste combustion facility flue gases, used primarily to control acid gases, but also to remove some heavy metals.

Signal Word: warning required by the Federal Hazardous Substances Act of 1960 to be used on the label of a hazardous substance. Examples include DANGER, WARNING, CAUTION, and POISON.

Sludge: heavy, slimy residue remaining from the treatment of municipal and industrial water and wastewater. Digested sewage sludge remains after decomposition under controlled temperature, pH, and mixing in a digester tank.

Softening: process of removing hardness caused by calcium and magnesium minerals from water.

Soil Liner: landfill liner composed of compacted soil or synthetic material designed to assist in containment of leachate.

Solid Waste Management: related to storage, collection, transportation, treatment, utilization, processing, and final disposal of solid waste or resource recovery, and facilities necessary for such activities.

Solubility: amount of a substance that will dissolve in a given amount of another substance, typically water.

Soluble: capable of being dissolved easily.

Solvent: liquid capable of dissolving another substance.

Source Reduction: design, nanufacture, acquisition, and reuse of materials so as to minimize the quantity and/or toxicity of waste produced. Waste is eliminated by redesigning products or by otherwise changing societal patterns of consumption, use, and waste generation.

Source Separation: segregation of specific recyclable materials at the point of generation for separate collection; often part of a curbside recycling program to facilitate reuse, recycling, and composting.

Special Waste: items that require special or separate handling, such as household hazardous waste, bulky waste, tires, and used oil.

Static Water Level: water level in a well before pumping.

Subsidy: direct or indirect payment from government to businesses, citizens, or institutions to encourage a desired activity.

Superfund: common name for the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) designed to clean up abandoned or inactive hazardous waste dump sites.

Tipping Fee: Charge, usually in dollars per ton, for the unloading or dumping of waste at a landfill, transfer station, recycling center, or waste-to-energy facility, also called a disposal or service fee.

Tipping floor: unloading area for vehicles that are delivering MSW to a transfer station or incinerator.

Total Dissolved Solids (TDS): concentration of all substances dissolved in water (solids remaining after evaporation of a water sample).

Toxic Substance (Toxicant): harmful to plant or animal life, either immediately (acute toxicity) or over a long time period (chronic toxicity).

Transfer: the act of moving waste from a collection vehicle to a larger transport vehicle.

Transfer point: a designated point, often at the edge of a neighborhood, where collection vehicles transfer waste to larger vehicles for transport to disposal sites.

Transfer Station: site where waste materials are taken and temporarily stored after collection, pending shipment to a disposal site or resource recovery facility. Recycling and some processing may also take place at transfer stations.

Transition countries: the countries of Eastern Europe and the former Soviet Union that are in various stages of restructuring their economies. The changes involve a move away from being substantially staterun toward a variety of new configurations, ranging from moderate economic liberalization to a significant dismantling of the state's role in the economy.

Transmissivity: rate at which water passes through a unit width of an aquifer.

Trash: Material considered worthless, unnecessary or offensive that is usually thrown away. In common usage, it is a synonym for garbage, rubbish or refuge.

Tub Grinder: Machine to grind or chip wood wastes for mulching, composting or size reduction.

Turbidity: measure of water cloudiness due to suspended solids.

Unconfined (Water Table) Aquifer: water-bearing formation whose upper boundary is the water table (as opposed to a confining layer).

Unsaturated Zone: portion of the soil profile which contains both air and water. Water in this zone cannot enter a well.

Vector: a carrier, typically an insect or rodent, capable of transmitting a disease. Organisms that carry disease causing pathogens. At landfills rodents, flies, and birds are the main vectors that spread pathogens beyond the landfill site.

Vermiculture: see worm culture.

Virgin Material: raw materials which have never been processed in a manufacturing system, usually requiring more energy to produce than when substituted for by recyclable materials for example, wood-pulp trees, iron ore, crude oil, bauxite.

Volatilization: conversion of substance to gaseous form.

Volume Reduction: the processing of waste materials so as to decrease the amount of space the materials occupy, usually by compacting or shredding (mechanical), incineration (thermal), or composting (biological).

Waste characterization study: an analysis of samples from a waste stream to determine its composition.

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 Exchange: a computer and catalog network that redirects waste materials back into the manufacturing or reuse process by matching companies generating specific waste with companies that use those wastes as manufacturing inputs.

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 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 Stream: the total waste generated by all contributors (households, industry, government) in a particular area (city, county, state).

Waste-to-energy (WTE) plant: a facility that uses solid waste materials (processed or raw) to produce energy. WTE plants include incinerators that produce steam for district heating or industrial use, or that generate electricity; they also include facilities that convert landfill gas to electricity.

Wastewater Treatment Plant (WWTP): facility that treats wastewater (and sometimes runoff) from domestic and/or industrial sources by a combination of physical, chemical, and biological processes.

Water Table: top of an unconfined aquifer, below which the pore spaces are saturated with water.

Watershed (Drainage Basin): all land and water that drains runoff to a stream or other surface water body.

Waterwall Incinerator: waste combustion facility using lined steel tubes filled with circulating water for cooling. Heat from the combustion gases is transferred to the water, and the resultant steam is sold or used to generate electricity.

Wetlands: areas that are regularly wet or flooded and have a water table that stands at or above the land surface for at least part of the year. Coastal wetlands extend back from estuaries and include salt marshes, tidal basins, marshes, and mangrove swamps. Inland freshwater wetlands consist of swamps, marshes, and bogs.

White Goods: Large household appliances such as refrigerators, stoves, air conditioners and washing machines.

Windrow: 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.

Working face: the length and width of the row in which waste is being deposited at a landfill. Also known as the tipping face.

Worm 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 venniculture.

Yard waste: leaves, grass clippings, prunings, and other natural organic matter discarded from yards and gardens.

Zoning: designation by ordinances of areas of land reserved and regulated for different land uses; a type of regulatory ordinance based on a land use plan.