Environ in terms

8/14/2019 Environ in terms

1/34

Pollution Prevention and Abatement HandbookWORLD BANK GROUPEffective July 1998

Glossary of Environmental Terms

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

Absorption. The passage of one substance intoor through another; e.g., an operation in whichone or more soluble components of a gas mixtureare dissolved in a liquid.

Accident site. The location of an unexpected occurrence,failure, or loss, either at a plant or alonga transportation route, resulting in a release ofhazardous materials.

Acid deposition. A complex chemical and atmosphericphenomenon that occurs when emissionsof sulfur and nitrogen compounds and other substancesare transformed by chemical processesin the atmosphere, often far from the original

sources, and then deposited on earth in either awet or a dry form. The wet forms, popularlycalled acid rain,can fall as rain, snow, or fog.The dry forms are acidic gases or particulates.

Acid rain. See Acid deposition

Activated carbon. A highly adsorbent form ofcarbon used to remove odors and toxic substancesfrom liquid or gaseous emissions. Inwaste treatment, it is used to remove dissolvedorganic matter from wastewater. It is also usedin motor vehicle evaporative control systems.

Activated sludge. Residue that results when primaryeffluent is mixed with bacteria-laden sludgeand then agitated and aerated to promote biologicaltreatment. This speeds breakdown of or

ganic matter in raw sewage undergoing secondarywastewater treatment.

Active ingredient. In any pesticide product, thecomponent that kills, or otherwise controls, targetpests. Pesticides are regulated primarily on

the basis of active ingredients.

Acute exposure. A single exposure to a toxic substancethat results in severe biological harm ordeath. Acute exposures are usually characterizedas lasting no longer than a day.

Acute toxicity. The ability of a substance to causepoisonous effects resulting in severe biologicalharm or death soon after a single exposure or


2/34

dose; also, any severe poisonous effect resultingfrom a single short-term exposure to a toxic substance.See also Chronic toxicity; Toxicity

Adaptation. Changes in an organisms structureor habit that help it adjust to its surroundings.

Add-on control device. An air pollution controldevice such as a carbon adsorber or incineratorthat reduces the pollution in an exhaustgas. The control device usually does not affectthe process being controlled and thus is addontechnology as opposed to a scheme to controlpollution by making some alteration to thebasic process.

Adsorption. 1. Adhesion of molecules of gas, liquid,or dissolved solids to a surface. 2. An advancedmethod of treating wastes in which

Note: This glossary is based on United States Environmental Protection Agency, Office of Communications and PublicAffairs, Glossary of Environmental Terms and Acronym List,19K-1002 (Washington, D

.C., December 1989).

441


3/34

442 POLLUTION PREVENTION AND ABATEMENT HANDBOOK

activated carbon removes organic matter fromwastewater.

Advanced wastewater treatment. Any treatmentof sewage that goes beyond the secondary or biologicalwater treatment stage and includes theremoval of nutrients such as phosphorus and nitrogenand a high percentage of suspended solids.See also Primary wastewater treatment;Secondary wastewater treatment

Aeration. A process that promotes biologicaldegradation of organic water. The process maybe passive (as when waste is exposed to air), oractive (as when a mixing or bubbling device introducesthe air).

Aerobic. Life or processes that require, or are notdestroyed by, the presence of oxygen. See alsoAnaerobic

Aerobic treatment. Process by which microbesdecompose complex organic compounds in thepresence of oxygen and use the liberated energyfor reproduction and growth. Types ofaerobic processes include extended aeration,trickling filtration, and rotating biologicalcontactors.

Aerosol. A suspension of liquid or solid particlesin a gas.

Agricultural pollution. The liquid and solidwastes from farming, including runoff and leaching

of pesticides and fertilizers; erosion and dustfrom plowing; animal manure and carcasses; andcrop residues and debris.

Airborne particulates. Total suspended particulatematter found in the atmosphere as solidparticles or liquid droplets. The chemical compositionof particulates varies widely, dependingon location and time of year. Airborneparticulates include windblown dust, emissionsfrom industrial processes, smoke from the burningof wood and coal, and the exhaust of motorvehicles.

Air mass. A widespread body of air that gains certainmeteorological or polluted characteristics

for example, a heat inversion or smokinesswhile standing in one location. The characteristicscan change as the air mass moves away. Seealso Inversion

Air monitoring. See Monitoring.


4/34

Air pollutant. Any substance in air that could,in high enough concentration, harm human beings,other animals, vegetation, or material. Pollutantsmay include almost any natural orartificial composition of matter capable of beingairborne. They may be in the form of solid particles,liquid droplets, gases, or combinations ofthese states. Generally, they fall into two maingroups: (a) those emitted directly from identifiablesources and (b) those produced in the air byinteraction between two or more primary pollutantsor by reaction with normal atmospheric constituents,with or without photoactivation.Exclusive of pollen, fog, and dust, which are ofnatural origin, about 100 contaminants have beenidentified. They fall into the following categories:solids, sulfur compounds, volatile organic chemicals,nitrogen compounds, oxygen compounds,halogen compounds, radioactive compounds,and odors.

Air pollution. The presence of contaminant orpollutant substances in the air that do not disperse

properly and interfere with human healthor welfare or produce other harmful environmentaleffects.

Air pollution episode. A period of abnormallyhigh concentration of air pollutants, often due tolow winds and temperature inversion, that cancause illness and death. See also Inversion

Algae. Simple rootless plants that grow in sunlitwaters in relative proportion to the amounts ofnutrients available. They can affect water qualityadversely by lowering the dissolved oxygen

in the water. Algae are food for fish and smallaquatic animals.

Algal blooms. Sudden spurts of algal growth thatcan affect water quality adversely and that indicatepotentially hazardous changes in local waterchemistry.


5/34

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

Anaerobic. A life or process that occurs in, or isnot destroyed by, the absence of oxygen.

Aquifer. An underground geological formation,or group of formations, containing usableamounts of groundwater that can supply wellsand springs.

Assimilation. The ability of a body of water topurify itself of pollutants.

Atmosphere (as a measurement). Astandard unitof pressure representing the pressure exerted bya 29.92-inch column of mercury at sea level at45 latitude and equal to 1,000 grams per squarecentimeter.

Attenuation. The process by which a compoundis reduced in concentration over time, throughadsorption, degradation, dilution, or transformation.

Background level. In air pollution control, theconcentration of air pollutants in a definite areaduring a fixed period of time prior to the startingup or on the stoppage of a source of emissionunder control. In toxic substances monitoring, theaverage presence in the environment, originallyreferring to naturally occurring phenomena.

Bacteria (singular: bacterium). Microscopic livingorganisms that can aid in pollution controlby consuming or breaking down organic matter

in sewage or by similarly acting on oil spills orother water pollutants. Bacteria in soil, water, orair can cause human, animal, and plant healthproblems.

Baghouse filter. Large fabric bag, usually madeof glass fibers, used to eliminate intermediate andlarge (greater than 20 microns in diameter) particles.This device operates in a way similar tothe bag of an electric vacuum cleaner, passing theair and smaller particulate matter while entrappingthe larger particulates.

Bar screen. In wastewater treatment, a deviceused to remove large solids.

Glossary of Environmental Terms 443

Benthic organism (benthos). A form of aquaticplant or animal life found on or near the bottomof a stream, lake, or ocean.

Bioaccumulative. Substances that are very


6/34

slowly metabolized or excreted by living organismsand thus increase in concentration withinthe organisms as the organisms breathe contaminatedair, drink contaminated water, or eatcontaminated food. See also Biological magnification

Bioassay. Using living organisms to measure theeffect of a substance, factor, or condition by comparingbefore-and-after data; often used to meancancer bioassays.

Biochemical oxygen demand (BOD). A measureof the amount of oxygen consumed in the biologicalprocesses that break down organic matterin water. The greater the BOD, the greater thedegree of pollution. In this Handbook, BOD isunderstood to be BOD5, the amount of dissolvedoxygen so consumed in five days.

Biodegradable. The ability to break down ordecompose rapidly under natural conditions andprocesses.

Biological control. In pest control, the use of animalsand organisms that eat or otherwise kill oroutcompete pests.

Biological magnification. Refers to the processwhereby certain substances such as pesticides orheavy metals move up the food chain, work theirway into a river or lake, and are eaten by aquaticorganisms such as fish, which in turn are eatenby large birds, animals, or humans. The substancesbecome concentrated in tissues or internalorgans as they move up the chain.

Biological oxidation. The way bacteria and microorganismsfeed on and decompose complexorganic materials; used in self-purification ofwater bodies and in activated sludge wastewatertreatment.

Biological treatment. A treatment technologythat uses bacteria to consume waste and thusbreak down organic materials.


7/34


Biomass. All the living material in a given area;often refers to vegetation. Also called biota.

Biomonitoring. 1. The use of living organismsto test the suitability of effluents for dischargeinto receiving waters and to test the quality ofsuch waters downstream from the discharge.

2. Analysis of blood, urine, tissues, etc., to measurechemical exposure in humans.Biotechnology. Techniques that use living organismsor parts of organisms to produce a varietyof productsfrom medicines to industrial enzymesto improve plants or animals or to developmicroorganisms for specific uses such as removingtoxics from bodies of water or for pesticides.

BOD5. The amount of dissolved oxygen consumedin five days by biological processes breakingdown organic matter.

Brackish water. A mixture of fresh and saltwater.

Bubble. A system under which existing emissionssources can propose alternate means for complyingwith a set of emissions limitations; under thebubble concept, sources can hold emissions to alower level, where this is cost-effective, in returnfor a comparable realization of controls at a secondemission point where costs are higher.

By-product. Material, other than the principalproduct, that is generated as a consequence of

an industrial process.

Cadmium (Cd). A heavy metal element that accumulatesin the environment.

Carbon adsorber. An add-on control device thatuses activated carbon to absorb volatile organiccompounds (VOCs) from a gas stream. The VOCsare later recovered from the carbon.

Carbon dioxide (CO2). A colorless, odorless, nonpoisonousgas that results from fossil fuel combustionand is normally a part of the ambient air.

Carbon monoxide (CO). A colorless, odorless,poisonous gas produced by incomplete fossil fuelcombustion.

Carcinogen. Any substance that can cause or contributeto the production of cancer.

Catalytic converter. An air pollution abatementdevice that removes pollutants from motor vehicle


8/34

exhaust, either by oxidizing them into carbondioxide and water or by reducing them tonitrogen and oxygen.

Catalytic incinerator. A control device that oxidizesvolatile organic compounds (VOCs) by usinga catalyst to promote the combustion process.Catalytic incinerators require lower temperaturesthan conventional thermal incinerators, yieldingfuel and cost savings.

Cells. 1. In solid waste disposal, holes in whichwaste is dumped, compacted, and covered withlayers of dirt on a daily basis. 2. The smalleststructural part of living matter capable of functioningas an independent unit.

Chemical oxygen demand (COD). A measure ofthe oxygen required to oxidize all compounds inwater, both organic and inorganic.

Chemical treatment. Any one of a variety of technologiesthat use chemicals or a variety of chemicalprocesses to treat waste.

Chlorinated hydrocarbons. A category whichincludes a class of persistent, broad-spectruminsecticides that linger in the environment andaccumulate in the food chain. Among them areDDT, aldrin, dieldrin, heptaclor, chlordane, lindane,endrin, mirex, hexachloride, and toxaphene.Trichloroethylene (TCE), used as anindustrial solvent, is also a chlorinated hydrocarbon.

Chlorinated solvent. An organic solvent containingchlorine atoms, e.g., methylene chloride and

1,1,1-trichloromethane, which is used in aerosolspray containers and in roadway paint.

Chlorination. The application of chlorine todrinking water, sewage, or industrial waste todisinfect or to oxidize undesirable compounds.

Chlorofluorocarbons (CFCs). A family of inert,nontoxic, and easily liquefied chemicals used in


9/34

refrigeration, air conditioning, packaging, andinsulation 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.

Chromium. See Heavy metals

Chronic toxicity. The capacity of a substance tocause long-term poisonous human health effects.See also Acute toxicity

Cleanup. Actions taken to deal with a release orthreat of release of a hazardous substance thatcould affect humans, the environment, or both.The term is sometimes used interchangeably withthe terms remedial action, removal action, responseaction, or corrective action.

Coagulation. A clumping of particles in wastewaterto settle out impurities; often induced bychemicals such as lime, alum, and iron salts.

Coliform index. A rating of the purity of waterbased on a count of fecal bacteria.

Coliform organism. Microorganisms found inthe intestinal tracts of humans and animals. Theirpresence in water indicates fecal pollution andpotentially dangerous bacterial contamination bydisease-causing microorganisms.

Combined sewers. A sewer system that carriesboth sewage and stormwater runoff. Normally,its entire flow goes to a waste treatment plant,but during a heavy storm the stormwater volume

may be so great as to cause overflows. When thishappens, untreated mixtures of stormwater andsewage may flow into receiving waters. Storm-water runoff may also carry toxic chemicals fromindustrial areas or streets into the sewer system.

Comminution. Mechanical shredding or pulverizingof waste; used in both solid waste managementand wastewater treatment.

Compaction. Reduction of the bulk of solid wasteby rolling and tamping.

Composting. The natural biological decompositionof organic material in the presence of air


to form a humus-like material. Controlledmethods of composting include mechanicalmixing and aerating, ventilating the materialsby dropping them through a vertical series ofaerated chambers, or placing the compost in


10/34

piles in the open air and mixing or turning itperiodically.

Contaminant. Any physical, chemical, biological,or radiological substance or matter that hasan adverse affect on air, water, or soil.

Conventional systems. Sewerage systems thathave been traditionally used to collect municipalwastewater in gravity sewers and convey itto a central primary or secondary treatment plantprior to discharge to surface waters.

Cooling tower. A structure that helps removeheat from water used as a coolant, e.g., in electricpower generating plants.

Corrosion. The dissolving and wearing away ofmetal caused by a chemical reaction that occursbetween water and the pipes that the water contacts,or when chemicals touching a metal surface,or when two metals are in contact.

Cover material. Soil used to cover compacted

solid waste in a sanitary landfill.

Cubic feet per minute (cfm). A measure of thevolume of a substance flowing through air withina fixed period of time. With regard to indoor air,refers to the amount of air, in cubic feet, that isexchanged with indoor air in a minutes time, oran air exchange rate.

Curie. A quantitative measure of radioactivityequal to 3.7 x 1010 disintegrations per second.

Cyclone collector. A device that uses centrifugal

force to pull large particles from pollutedair.

Decomposition. The breakdown of matter bybacteria and fungi; changes the chemical makeupand physical appearance of materials.

Degradation. The process by which a chemicalis reduced to a less complex form.


11/34


Denitrification. The anaerobic biological reductionof nitrate nitrogen to nitrogen gas.

Desulfurization. Removal of sulfur from fossilfuels to reduce pollution.

Detergent. Synthetic washing agent that helpsto remove dirt and oil. Some detergents containcompounds that kill useful bacteria and encouragealgal growth when they are discharged inwastewater that reaches receiving waters.

Digester. In wastewater treatment, a closed tank;in solid waste conversion, a unit in which bacterialaction is induced and accelerated to breakdown organic matter and establish the propercarbon-to-nitrogen ratio.

Dilution ratio. The relationship between the volumeof water in a stream and the volume of incomingwater; it affects the ability of the stream

to assimilate waste.

Dioxin. Any of a family of compounds knownchemically as dibenzo-p-dioxins. Concern aboutthem arises from their potential toxicity and contaminationin commercial products. Tests on laboratoryanimals indicate that it is one of the moretoxic man-made chemicals known.

Disinfectant. A chemical or physical process thatkills pathogenic organisms in water. Chlorine isoften used to disinfect sewage treatment effluent,water supplies, wells, and swimming pools.

Dispersant. A chemical agent used to break up concentrationsof organic material such as spilled oil.

Disposal. Final placement or destruction of toxic,radioactive, or other wastes; surplus or bannedpesticides or other chemicals; polluted soils; anddrums containing hazardous materials from removalactions or accidental releases. Disposalmay be accomplished through use of approvedsecure landfills, surface impoundments, landfarming, deep well injection, ocean dumping, orincineration.

Dissolved oxygen (DO). The oxygen freely availablein water; vital to fish and other aquatic life

and for the prevention of odors. Traditionally, thelevel of dissolved oxygen has been accepted asthe single most important indicator of the abilityof a water body to support desirable aquatic life.Secondary wastewater treatment and advancedwastewater treatment are generally designed to


12/34

protect DO in waste-receiving waters.

Dissolved solids. Disintegrated organic and inorganicmaterial contained in water. Excessiveamounts make water unfit for drinking or for usein industrial processes.

Distillation. The act of purifying liquids throughboiling so that the steam condenses to a pure liquidand the pollutants remain in a concentratedresidue.

Dump. A site used to dispose of solid wasteswithout environmental controls.

Ecology. The relationship of living things to oneanother and their environment, or the study ofsuch relationships.

Ecosystem. The interacting system of a biologicalcommunity and its nonliving environmentalsurroundings.

Effluent. Wastewatertreated or untreated

that flows out of a treatment plant, sewer, or industrialoutfall; generally refers to wastesdischarged into surface waters.

Effluent limitation. Restrictions established bya national environmental agency or by asubnational jurisdiction on quantities, rates, andconcentrations in wastewater discharges.

Electrostatic precipitator (ESP). An air pollutioncontrol device that removes particles froma gas stream (smoke) after combustion occurs.The ESP imparts an electrical charge to the particles,

causing them to adhere to metal platesinside the precipitator. Rapping on the platescauses the particles to fall into a hopper fordisposal.

Emission. Pollution discharged into the atmospherefrom smokestacks, other vents, and sur


13/34

face areas of commercial or industrial facilities,from residential chimneys; and from motor vehicle,locomotive, or aircraft exhausts.

Emission factor. The relationship between theamount of pollution produced and the amountof raw material processed. For example, an emissionfactor for a blast furnace making iron wouldbe the number of pounds of particulates per tonof raw material.

Emission standard. The maximum amount of air-polluting discharge legally allowed from a singlesource, mobile or stationary.

Enrichment. The addition of nutrients (e.g., nitrogen,phosphorus, or carbon compounds) fromsewage effluent or agricultural runoff to surfacewater. This process greatly increases the growthpotential of algae and aquatic plants.

Environment. The sum of all external conditionsaffecting the life, development, and survival of

an organism.

Environmental assessment (EA). A processwhose breadth, depth, and type of analysis dependon the proposed project. EA evaluates aprojects potential environmental risks and impactsin its area of influence and identifies waysof improving project design and implementationby preventing, minimizing, mitigating, or compensatingfor adverse environmental impacts andby enhancing positive impacts.

Environmental audit. 1. An independent assessment

of the current status of a partys compliancewith applicable environmental requirements.

2. An independent evaluation of a partys environmentalcompliance policies, practices, andcontrols.Eutrophication. The slow aging process duringwhich a lake, estuary, or bay evolves into a bogor marsh and eventually disappears. During thelater stages of eutrophication the water body ischoked by abundant plant life as the result ofincreased amounts of nutritive compounds suchas nitrogen and phosphorus. Human activities

can accelerate the process.


Evapotranspiration. The loss of water from thesoil both by evaporation and by transpirationfrom the plants growing in the soil.

Exposure. A potential health threat to the livingorganisms in the environment due to the amount


14/34

of radiation or pollutant present in the environment.

Fabric filter. A cloth device that catches dust particlesfrom industrial emissions.

Fecal coliform bacteria. Bacteria found in theintestinal tracts of mammals. Their presence inwater or sludge is an indicator of pollution andpossible contamination by pathogens.

Fertilizer. Materials such as nitrogen and phosphorusthat provide nutrients for plants. Commerciallysold fertilizers may contain otherchemicals or may be in the form of processed sewagesludge.

Filtration. A treatment process, under the controlof qualified operators, for removing solid (particulate)matter from water by passing the waterthrough porous media such as sand or a man-made filter. The process is often used to removeparticles that contain pathogenic organisms.

Flocculation. The process by which clumps of

solids in water or sewage are made to increase insize by biological or chemical action so that theycan be separated from the water.

Flowmeter. A gauge that shows the speed ofwastewater moving through a treatment plant;also used to measure the speed of liquids movingthrough various industrial processes.

Flue gas. Vented air coming out of a chimneyafter combustion in the burner; can include nitrogenoxides, carbon oxides, water vapor, sulfuroxides, particles, and many chemical

pollutants.

Flue gas desulfurization. A technology that usesa sorbent, usually lime or limestone, to removesulfur dioxide from the gases produced by burningfossil fuels. Flue gas desulfurization is currentlythe state-of-the-art technology in use by


15/34


major sulfur dioxide emitters such as powerplants.

Fluorides. Gaseous, solid, or dissolved compoundscontaining fluorine that result from industrialprocesses; excessive amounts in food canlead to fluorosis.

Fluorocarbon (FCs). Any of a number of organiccompounds analogous to hydrocarbons in whichone or more hydrogen atoms are replaced by fluorine.Once used in the United States as a propellantin aerosols, they are now primarily used incoolants and some industrial processes. FCs containingchlorine are called chlorofluorocarbons(CFCs). They are believed to be modifying theozone layer in the stratosphere, thereby allowingmore harmful solar radiation to reach theEarths surface.

Fly ash. Noncombustible residual particles from

the combustion process carried by flue gas.

Food chain. A sequence of organisms each ofwhich uses the next lower member of the sequenceas a food source.

Fugitive emissions. Emissions not caught by acapture system.

Geiger counter. An electrical device that detectsthe presence of certain types of radioactivity.

Generator. A facility or mobile source that emits

pollutants into the air or releases hazardouswastes into water or soil.

Granular activated carbon (GAC) treatment. Afiltering system often used in small water systemsand individual homes to remove organics.GAC can be highly effective in removing elevatedlevels of radon from water.

Greenhouse effect. The warming of the Earthsatmosphere caused by a buildup of carbon dioxideor other trace gases; many scientists believethat this buildup allows light from the suns rays

to heat the Earth but prevents a counterbalancingloss of heat.

Groundwater. The supply of fresh water foundbeneath the Earths surface (usually in aquifers),which is often used for supplying wellsand springs. Because groundwater is a majorsource of drinking water, there is growing concernabout areas where leaching agriculturalor industrial pollutants or substances from


16/34

leaking underground storage tanks are contaminatingit.

Habitat. The place where a population (e.g., human,animal, plant, or microorganism) lives, andits surroundings, both living and nonliving.

Half-life. 1. The time required for a pollutant tolose half its effect on the environment. For example,the half-life of DDT in the environment is15 years and that of radium is 1,580 years. 2. Thetime required for half of the atoms of a radioactiveelement to undergo decay. 3. The time requiredfor the elimination of half of a total dosefrom the body.

Hazardous wastes. By-products of society thatcan pose a substantial or potential hazard to humanhealth or the environment when improperlymanaged. Substances classified as hazardouswastes possess at least one of four characteristicsignitability, corrosivity, reactivity, ortoxicityor appear on special lists.

Heavy metals. Metallic elements with atomicnumber greater than 20, such as mercury and lead.They can damage living things at low concentrationsand tend to accumulate in the food chain.

Herbicide. A chemical pesticide designed to controlor destroy plants, weeds, or grasses.

Holding pond. A pond or reservoir, usually madeof earth, built to store polluted runoff.

Hydrocarbons (HC). Chemical compounds thatconsist entirely of carbon and hydrogen.

Hydrogen sulfide (HS). Gas emitted during organicdecomposition and as a by-product of oilrefining and burning. It smells like rotten eggsand, in heavy concentration, can cause illness.


17/34

Hydrology. The science dealing with the properties,distribution, and circulation of water.

Impoundment. A body of water or sludge confinedby a dam, dike, floodgate, or other barrier.

Incineration. 1. Burning of certain types of solid,liquid, or gaseous materials. 2. A treatment technologyinvolving destruction of waste by controlledburning at high temperatures, e.g.,burning sludge to remove the water and reducethe remaining residues to a safe, nonburnable ashthat can be disposed of safely on land, in somewaters, or in underground locations.

Incinerator. A furnace for burning wastes undercontrolled conditions.

Indicator. In biology, an organism, species, orcommunity whose characteristics show the presenceof specific environmental conditions.

Indirect discharge. Introduction of pollutantsfrom a nondomestic source into a publicly ownedwaste treatment system. Indirect dischargers canbe commercial or industrial facilities whosewastes go into the local sewers.

Infiltration. 1. The penetration of water throughthe ground surface into subsurface soil or thepenetration of water from the soil into sewer orother pipes through defective joints, connections,or manhole walls. 2. A land application techniquewhereby large volumes of wastewater are appliedto land and allowed to penetrate the surface and

percolate through the underlying soil. See alsoPercolation

Inorganic chemicals. Chemical substances ofmineral origin, not of basically carbon structure.

Insecticide. A pesticide compound specificallyused to kill or control the growth of insects.

Instream use. Water use taking place within astream channel, e.g., hydroelectric power generation,navigation, water quality improvement, fishpropagation, or recreation.


Inversion. An atmospheric condition that occurswhen a layer of warm air prevents the riseof cooling air trapped beneath it. This in turnprevents the rise of pollutants that might otherwisebe dispersed and can cause an air pollutionepisode.


18/34

Ion exchange treatment. A water-softeningmethod often found on a large scale at waterpurification plants; the treatment removes someorganics and radium by adding calcium oxideor calcium hydroxide to increase the pH to a levelat which the metals will precipitate out.

Irrigation. Technique for applying water orwastewater to land areas to supply the water andnutrient needs of plants.

Lagoon. 1. A shallow pond in which sunlight,bacterial action, and oxygen work to purifywastewater; also used for storage of wastewatersor spent nuclear fuel rods. 2. A shallow body ofwater, often separated from the sea by coral reefsor sandbars.

Land application. Discharge of wastewateronto the ground for treatment or reuse. See alsoIrrigation

Landfills. 1. Sanitary landfills are land disposalsites for nonhazardous solid wastes at which

wastes are spread in layers, compacted to thesmallest practical volume, and covered at the endof each operating day. 2. Secure chemical landfillsare disposal sites for hazardous wastes that areselected and designed to minimize the chanceof release of hazardous substances into the environment.

Leachate. A liquid that results when water collectscontaminants as it trickles through wastes,agricultural pesticides, or fertilizers.

Leaching. The process by which soluble constituents

are dissolved and carried down through thesoil by a percolating fluid. Leaching may occurin farming areas, feedlots, and landfills and mayresult in hazardous substances entering surfacewater, groundwater, or soil. See also Leachate


19/34


Limnology. The study of the physical, chemical,meteorological, and biological aspects of freshwater.

Liner. 1. A relatively impermeable barrier designedto prevent leachate from leaking from alandfill. Liner materials include plastic and denseclay. 2. An insert or sleeve for sewer pipes to preventleakage or infiltration.

Mechanical aeration. Use of mechanical energyto inject air into water, causing a waste stream toabsorb oxygen.

Methane. A colorless, nonpoisonous, flammablegas created by anaerobic decomposition of organiccompounds.

Microbes. Microscopic organisms such as algae,viruses, bacteria, fungi, and protozoa, some ofwhich cause disease.

Mitigation. Measures taken to reduce adverseimpacts on the environment.

Mixed liquor. A mixture of activated sludge andwater containing organic matter undergoing activatedsludge treatment in an aeration tank.

Mobile source. A moving producer of air pollution,mainly forms of transport such as cars,trucks, motorcycles, and airplanes.

Modeling. An investigative technique using a

mathematical or physical representation of a systemor theory that accounts for all or some of itsknown properties. Models are often used to testthe effect of changes in system components onthe overall performance of the system.

Monitoring. Periodic or continuous surveillanceor testing to determine the level of compliancewith statutory requirements or pollutant levelsin various media or in humans, animals, andother living things.

Monitoring wells. Wells drilled at a site to collect

groundwater samples for the purpose ofphysical, chemical, or biological analysis to determinethe amounts, types, and distribution of

contaminants in the groundwater beneath thesite.

Mutagen. Any substance that can cause a changein genetic material.


20/34

Neutralization. Decreasing the acidity or alkalinityof a substance by adding to it alkaline oracidic materials, respectively.

Nitrate. A compound containing nitrogen thatcan exist in the atmosphere or as a dissolved gasin water and can have harmful effects on humansand animals. Nitrates in water can cause severeillness in infants and cows.

Nitric oxide (NO). A gas formed by combustionunder high temperature and high pressure in aninternal combustion engine. It changes to nitrogendioxide in the ambient air and contributes tophotochemical smog.

Nitrification. The process whereby ammonia inwastewater is oxidized to nitrite and then to nitrateby bacterial or chemical reactions.

Nitrogen dioxide (NO2). The result of nitric oxidecombining with oxygen in the atmosphere; amajor component of photochemical smog.

Nitrogenous wastes. Animal or vegetable residuesthat contain significant amounts of nitrogen.

Nitrogen oxides (NOx). Products of combustionfrom transport and stationary sources and majorcontributors to acid deposition and the formationof ground-level ozone in the troposphere.

Nonpoint sources. Pollution sources that are diffuseand do not have a single point of origin orare not introduced into a receiving stream froma specific outlet. The pollutants are generally carriedoff the land by storm-water runoff. The commonly

used categories for nonpoint sources areagriculture, forestry, urban, mining, construction,dams and channels, land disposal, and saltwaterintrusion.

Nutrient. Any substance assimilated by livingthings that promotes growth. The term is gener


21/34

ally applied to nitrogen and phosphorus in wastewaterbut is also applied to other essential andtrace elements.

Organic. 1. Referring to or derived from livingorganisms. 2. In chemistry, any compound containingcarbon.

Organic chemicals/compounds. Animal- orplant-produced substances containing mainlycarbon, hydrogen, and oxygen.

Organophosphates. Pesticide chemicals that containphosphorus; used to control insects. They areshort-lived, but some can be toxic when firstapplied.

Outfall. The place where an effluent is dischargedinto receiving waters.

Overburden. The rock and soil cleared away beforemining.

Overland flow. A land application technique thatcleanses waste by allowing it to flow over asloped surface. As the water flows over the surface,the contaminants are removed. The wateris collected at the bottom of the slope for reuse.

Oxidation. 1. The addition of oxygen, whichbreaks down organic waste or chemicals such ascyanides, phenols, and organic sulfur compoundsin sewage by bacterial and chemicalmeans. 2. Oxygen combining with other elements.3. The process in chemistry whereby electronsare removed from a molecule.

Oxidation pond. A man-made lake or body ofwater in which liquid waste is consumed by bacteria.It is used most frequently with other water-treatment processes. An oxidation pond isbasically the same as a sewage lagoon.

Ozone (O3). Found in two layers of the atmosphere,the troposphere and the stratosphere. Inthe troposphere (the layer extending 7 to 10 milesup from the Earths surface), ozone is a chemicaloxidant and major component of photochemicalsmog. In the stratosphere (the atmospheric

layer beginning 7 to 10 miles above the Earths


surface), ozone is a form of oxygen found naturallythat provides a protective layer shieldingthe Earth from the harmful health effects of ultravioletradiation on humans and the environment.


22/34

Ozone depletion. Destruction of the stratosphericozone layer that shields the Earth fromultraviolet radiation harmful to biological life.This destruction of ozone is caused by the breakdownof certain chlorine- or bromine-containingcompounds (chlorofluorocarbons or halons) thatbreak down when they reach the stratosphere andcatalytically destroy ozone molecules.

Particulates. Fine liquid or solid particles, suchas dust, smoke, mist, fumes, or smog, found inair or emissions.

Pathogenic. Capable of causing disease.

Pathogens. Microorganisms that can cause diseasein other organisms or in humans, other animals,and plants. They may be bacteria, viruses,or parasites and are found in sewage, in runofffrom animal farms or rural areas populated withdomestic or wild animals, and in water used forswimming. Fish and shellfish contaminated bypathogens, or the contaminated water itself, cancause serious illness.

Percolation. The movement of water downwardand radially through the subsurface soil layers, usuallycontinuing downward to the groundwater.

Permeability. The rate at which liquids passthrough soil or other materials in a specifieddirection.

Permit. An authorization, license, or equivalentcontrol document issued by an approved agencyto implement the requirements of an environmentalregulation; e.g., a permit to operate a

wastewater treatment plant or to operate a facilitythat may generate harmful emissions.

Persistence. Refers to the length of time a compound,once introduced into the environment,stays there. A compound may persist for less thana second or indefinitely.


23/34


24/34

leaking from a damaged reactor. 3. The distancefrom a toxic release considered dangerous forthose exposed to the leaking fumes.

Point source. A stationary location or fixed facilityfrom which pollutants are discharged or emitted;any single identifiable source of pollution, e.g., apipe, ditch, ship, ore pit, or factory smokestack.

Pollutant. Generally, the presence of matter orenergy whose nature, location, or quantity producesundesired environmental effects. Under the

U.S. Clean Water Act, for example, the term isdefined as the man-made or man-induced alterationof the physical, biological, and radiologicalintegrity of water.Polychlorinated biphenyls (PCBs). a group oftoxic, persistent chemicals used in transformersand capacitators for insulating purposes and ingas pipeline systems as a lubricant.

Polyelectrolytes. Synthetic chemicals that helpsolids to clump during sewage treatment.

Polymers. The basic molecular ingredients inplastic.

Polyvinyl chloride (PVC). A tough, environmentallyindestructible plastic that releases hydrochloricacid when burned.

Potable water. Water that is safe for drinking andcooking.

ppm/ppb. Parts per million/parts per billion, away of expressing tiny concentrations of pollutants

in air, water, soil, human tissue, and foodand or other products.

Precipitation. Removal of solids from liquidwaste so that the hazardous solid portion can be


25/34

disposed of safely; removal of particles from airborneemissions.

Precipitators. Air pollution control devices thatcollect particles from an emission.

Precursor. In photochemical terminology, a compoundsuch as a volatile organic compound(VOC) that precedesan oxidant. Precursorsreact in sunlight to form ozone or other photochemicaloxidants.

Pretreatment. Processes used to reduce, eliminate,or alter the nature of wastewater pollutantsfrom nondomestic sources before they aredischarged into publicly owned treatmentworks.

Prevention. Measures taken to minimize the releaseof wastes to the environment.

Primary wastewater treatment. First steps inwastewater treatment; screens and sedimentation

tanks are used to remove most materials that floator will settle. Primary treatment results in theremoval of about 30% of carbonaceous biochemicaloxygen demand (BOD) from domestic sewage.See also Secondary wastewater treatment;tertiary wastewater treatment

Putrescible. Able to rot quickly enough to causeodors and attract flies.

Pyrolysis. Decomposition of a chemical by extremeheat.

Radiobiology. The study of the effects of radiationon living things.

Radiation. Any form of energy propagated asrays, waves, or streams of energetic particles. Theterm is frequently used in relation to the emissionof rays from the nucleus of an atom.

Raw sewage. Untreated wastewater.

Receiving waters. A river, lake, ocean, stream,or other watercourse into which wastewater ortreated effluent is discharged.


Recycle/reuse. The process of minimizing thegeneration of waste by recovering usable productsthat might otherwise become wastes. Examplesare the recycling of aluminum cans, wastepaper, and bottles.

Red tide. A proliferation of a marine plankton


26/34

that is toxic and often fatal to fish. This natural phenomenonmay be stimulated by the addition of nutrients.A tide can be called red, green, or brown,depending on the coloration of the plankton.

Refuse. See Solid waste

Residual. Amount of a pollutant remaining inthe environment after a natural or technologicalprocess has taken place, e.g., the sludge remainingafter initial wastewater treatment, or particulatesremaining in air after the air passes througha scrubbing or other pollutant removal process.

Resistance. For plants and animals, the abilityto withstand poor environmental conditions orattacks by chemicals or disease. The ability maybe inborn or developed.

Resource recovery. The process of obtainingmatter or energy from materials formerly discarded.

Reverse osmosis. A water treatment process used

in small water systems by adding pressure toforce water through a semipermeable membrane,Reverse osmosis removes most drinking watercontaminants. It is also used in wastewater treatment.Large-scale reverse osmosis plants are nowbeing developed.

Risk assessment. The qualitative and quantitativeevaluation performed in an effort to definethe risk posed to human health or the environmentby the presence or potential presence anduse of specific pollutants.

Rubbish. Solid waste, excluding wood waste andashes, from homes, institutions, and workplaces.

Runoff. That part of precipitation, snowmelt, orirrigation water that runs off the land into streams


27/34


or other surface water; can carry pollutants fromthe air and land into the receiving waters.

Salinity. The degree of salt in water.

Salts. Minerals that water picks up as it passesthrough the air and over and under the groundand as it is used by households and industry.

Sand filters. Devices that remove some suspendedsolids from sewage. Air and bacteria decomposeadditional wastes filtering through thesand so that cleaner water drains from the bed.

Sanitary landfill. See Landfills

Sanitary sewers. Underground pipes that carryoff only domestic or industrial waste, notstormwater.

Sanitation. Control of physical factors in the environment

that could harm human development,health, or survival.

Screening. Use of screens to remove coarse floatingand suspended solids from sewage.

Scrubber. An air pollution device that uses aspray of water or reactant or a dry process to trappollutants in emissions.

Secondary wastewater treatment. The secondstep in most publicly owned water treatmentsystems, in which bacteria consume the organic

parts of the waste. It is accomplished by bringingtogether waste, bacteria, and oxygen in tricklingfilters or in the activated sludge process. Thistreatment removes floating and settleable solidsand about 90% of the oxygen-demanding substancesand suspended solids. Disinfection is thefinal stage of secondary treatment. See also Primarywastewater treatment; Tertiary wastewatertreatment

Sedimentation. Letting solids settle out of wastewaterby gravity during wastewater treatment.

Sedimentation tanks. Holding areas for wastewaterin which floating wastes are skimmed offand settled solids are removed for disposal.

Sediments. Soil, sand, and minerals washed fromland into water, usually after rain. Sediments pileup in reservoirs, rivers, and harbors, destroyingfish-nesting areas and holes of water animals andclouding the water so that needed sunlight maynot reach aquatic plants. Careless farming, mining,


28/34

and building activities will expose sedimentmaterials, allowing them to be washed off theland after rainfalls.

Septic tank. An underground storage tank forwastes from homes having no sewer line to atreatment plant. The wastes go directly from thehome to the tank, where the organic waste is decomposedby bacteria and the sludge settles tothe bottom. The effluent flows out of the tank intothe ground through drains; the sludge is pumpedout periodically.

Settleable solids. Material heavy enough to sinkto the bottom of a wastewater treatment tank.

Settling tank. A holding area for wastewater inwhich heavier particles sink to the bottom forremoval and disposal.

Sewage. The waste and wastewater produced byresidential and commercial establishments anddischarged into sewers.

Sewage sludge. Sludge produced at a municipaltreatment works.

Sewer. A channel or conduit that carries wastewaterand stormwater runoff from the source toa treatment plant or receiving stream. Sanitarysewers carry household, industrial, and commercialwastes. Storm sewers carry runoff from rainor snow. Combined sewers are used for both purposes.

Silt. Fine particles of sand or rock that can bepicked up by the air or water and deposited as

sediment.

Siting. The process of choosing a location for afacility.

Skimming. Using a machine to remove oil orscum from the surface of the water.


29/34

Slow sand filtration. Treatment process involvingpassage of raw water through a bed of sandat low velocity that results in the substantialremoval of chemical and biological contaminants.

Sludge. A semisolid residue from any of a numberof air or water treatment processes. Sludgecan be a hazardous waste.

Slurry. A watery mixture of insoluble matterthat results from some pollution control techniques.

Smelter. A facility that melts or fuses ore, oftenwith an accompanying chemical change, to separatethe metal. Emissions from smelters areknown to cause pollution.

Smog. Fog made heavier and darker by smoke.Air pollution associated with oxidants. See alsoPhotochemical oxidants

Smoke. Particles suspended in air after incompletecombustion of materials.

Solid wastes. Nonliquid, nonsoluble materials,ranging from municipal garbage to industrialwastes, that contain complex, and sometimeshazardous, substances. Solid wastes includesewage sludge, agricultural refuse, demolitionwastes, and mining residues. Technically, solidwastes also refer to liquids and gases in containers.

Solid waste disposal. The final placement of

refuse that is not salvaged or recycled.

Solid waste management. Supervised handlingof waste materials from their source through recoveryprocesses to disposal.

Solidification and stabilization. Removal ofwastewater from a waste or changing it chemicallyto make the waste less permeable and lesssusceptible to transport by water.

Solvent. Substance (usually liquid) capable ofdissolving or dispersing one or more other substances.


Stabilization. Conversion of the active organicmatter in sludge into inert, harmless material.

Stable air. A mass of air that is not moving normally,so that it holds rather than disperses pollutants.


30/34

Stack. A chimney or smokestack; a vertical pipethat discharges used air.

Stack effect. Used air, as in a chimney, that movesupward because it is warmer than the surroundingatmosphere.

Sterilization. 1. In pest control, the use of radiationand chemicals to damage body cells needed for reproduction.2. The destruction of all living organismsin water or on the surface of various materials.In contrast, disinfection is the destruction of mostliving organisms in water or on surfaces.

Strip mining. A process that uses machines toscrape soil or rock away from mineral depositsjust under the earths surface.

Sulfur dioxide (SO2). A heavy, pungent, colorless,gaseous air pollutant formed primarily byprocesses involving fossil fuel combustion.

Sump. A pit or tank that catches liquid runoff

for drainage or disposal.

Surface water. All water naturally open to theatmosphere (rivers, lakes, reservoirs, streams,impoundments, seas, estuaries, etc.); also refersto springs, wells, or other collectors that are directlyinfluenced by surface water.

Surfactant. A surface-active agent used in detergentsto cause lathering.

Suspended solids. Small particles of solid pollutantsthat float on the surface of or are suspended

in sewage or other liquids. They resistremoval by conventional means. See also Totalsuspended solids

Tailings. Residue of raw materials or waste separatedout during the processing of crops or mineralores.


31/34


32/34

may carry pollutants of various kinds into sewersystems or receiving waters.

Vapor. The gaseous phase of substances that areliquid or solid at atmospheric temperature andpressure, e.g., steam.

Vapor capture system. Any combination of hoodsand ventilation system that captures or containsorganic vapors so that they may be directed toan abatement or recovery device.

Vector. 1. An organism, often an insect or rodent,that carries disease. 2. An object (e.g., plasmids,viruses, or other bacteria) used to transport genesinto a host cell. A gene is placed in the vector; thevector then infectsthe bacterium.

Vinyl chloride. A chemical compound, used inproducing some plastics, that is believed to becarcinogenic.

Volatile. Description of any substance that evaporatesreadily.

Volatile organic compound (VOC). Any organiccompound that participates in atmosphericphotochemical reactions; generallyhave a boiling point of less than 145 Celsius.See Anthony J. Buonicore and Wayne T. Davis,eds., Air Pollution Engineering Manual (NewYork: Van Nostrand Reinhold,1992), Table 7,

p. 45.Wastes. 1. Unwanted materials left over from amanufacturing process. 2. Refuse from places ofhuman or animal habitation.

Wastewater treatment plant. A facility containinga series of tanks, screens, filters, and otherprocesses by which pollutants are removed fromwater.


33/34

Wastewater treatment stream. The continuousmovement of wastes from generator to treaterand disposer.

Wastewater. Spent or used water from individualhomes, communities, farms, or industries thatcontains dissolved or suspended matter.

Wastewater operations and maintenance. Actionstaken after construction to ensure that facilitiesconstructed to treat wastewater will beproperly operated, maintained, and managed toachieve efficiency levels and prescribed effluentlevels in an optimum manner.

Water pollution. The presence in water of enoughharmful or objectionable material to damagewater quality.


Water quality criteria. Specific levels of waterquality that, if reached, are expected to render a

body of water suitable for its designated use. Thecriteria are based on specific levels of pollutantsthat would make the water harmful if used fordrinking, swimming, farming, fish production,or industrial processes.

Watershed. The land area that drains into astream.

Wetlands. An area that is regularly saturated bysurface water or groundwater and is subsequentlycharacterized by a prevalence of vegetationadapted for life in saturated soil conditions.

Examples include swamps, bogs, fens, marshes,and estuaries.


34/34

Environ in terms

Documents

Transcript of Environ in terms