A tank entirely above grade (natural or otherwise). (Note: for purposes of the SPCC regulation, the EPA arbitrarily defines partially buried, bunkered, and subterranean vaulted tanks as aboveground tanks.)

A process for removing organic matter from sewage by saturating it with air and adding biologically active sludge.

A stimulus severe enough to rapidly induce an effect; in aquatic toxicity tests, an effect observed in 96 hours or less is typically considered acute. When referring to aquatic toxicology or human health, an acute effect is not always measured in terms of lethality.

The binding of molecules or particles to a surface that is usually weak and reversible. The most common industrial adsorbents are activated carbon, silica gel, and alumina, because they present enormous surface areas per unit weight. Activated carbon has been used to remove organic matter from wastewater.

Plants which grow in sunlit waters and release oxygen into the water. They are a food for fish and small aquatic animals.

A discrete sample used for analysis.

Any work on a container involving cutting, burning, welding, or heating operations that changes the physical dimensions or configuration of the container.

A life or process that occurs in the absence of oxygen.

Policies which ensure protection of water quality for a particular water body where the water quality exceeds levels necessary to protect fish and wildlife propagation and recreation on and in the water. This also includes special protection of waters designated as outstanding natural resource waters. Antidegradation plans are adopted by each State to minimize adverse effects on water.

Any building or group of buildings, structures, or equipment which perform the same function or service, at the same location and under the same supervision.

As provided for by Sections 311(a)(18) and (j)(4) of the Clean Water Act (CWA), means the entity appointed by the President consisting of members from qualified personnel of Federal, State, and local agencies with responsibilities that include preparing an Area Contingency Plan for the area designated by the President. The Area Committee may include ex-officio (i.e., non-voting) members (e.g., industry and local interest groups).

As provided for by Sections 311(a)(19) and (j)(4) of CWA, means the plan prepared by an Area Committee that is developed to be implemented in conjunction with the NCP and RCP, in part to address removal of a worst case discharge and to mitigate or prevent a substantial threat of such a discharge from a vessel, offshore facility, or onshore facility operating in or near an Area designated by the President.

A State, Territorial, Tribal, or interstate NPDES program which has been approved or authorized by EPA under 40 CFR Part 123.

The highest allowable average of daily discharges over a calendar month, calculated as the sum of all daily discharges measured during that month divided by the number of days on which monitoring was performed (except in the case of fecal coliform).

The uses of water necessary for the survival or well being of man, plants, and wildlife. These uses of water serve to promote the tangible and intangible economic, social, and environmental goals. “Beneficial Uses” that may be protected against include, but are not limited to: domestic, municipal, agricultural and industrial supply; power generation; recreation; aesthetic enjoyment; navigation; and preservation and enhancement of fish, wildlife, and other aquatic resources or preserves.

BPT is the first level of technology-based standards established by EPA under the CWA to control pollutants discharged to waters of the U.S. for each class of industry emitting pollution.  BPT effluent limitations guidelines are generally based on the average of the best existing performance by plants within an industrial category or subcategory.

The method used by permit writers to develop technology-based NPDES permit conditions on a case-by-case basis using all reasonably available and relevant data.

The progressive accumulation of contaminants in the tissues of organisms through any route including respiration, ingestion, or direct contact with contaminated water, sediment, pore water, or dredged material to a higher concentration than in the surrounding environment.

A test used to evaluate the relative potency of a chemical or a mixture of chemicals by comparing its effect on a living organism with the effect of a standard preparation on the same type of organism.

A measurement of the amount of oxygen utilized by the decomposition of organic material, over a specified time period (usually 5 days) in a wastewater sample; it is used as a measurement of the readily decomposable organic content of a wastewater.

Nutrient-rich organic materials resulting from the treatment of domestic sewage in a treatment facility. When treated and processed, these residuals can be recycled and applied as a fertilizer to improve and maintain productive soils and stimulate plant growth. Uses include, but are not limited to, land application to agricultural land, forest land, a reclamation site or sale or give away to the public for home lawn and garden use.

The term given to any water that carries animal, human or food wastes.

The intentional diversion of wastestreams from any portion of a treatment (or pretreatment) facility.

A stimulus that lingers or continues for a relatively long period of time, often one-tenth of the life span or more. Chronic should be considered a relative term depending on the life span of an organism. The measurement of a chronic effect can be reduced growth, reduced reproduction, etc., in addition to lethality.

The clumping together of solids to make them settle out of the sewage faster. Coagulation of solids is brought about with the use of certain chemicals such as lime, alum and iron salts.

As defined in the NCP, for the purposes of classifying the size of discharges, the waters of the coastal zone except for the Great Lakes and specified ports and harbors on inland rivers. Precise boundaries are identified in U.S. Coast Guard/U.S. Environmental Protection Agency agreements, Federal Regional Contingency Plans and Area Contingency Plans.

As defined in the NCP, all United States waters subject to the tide, United States waters of the Great Lakes, specified ports and harbors on inland rivers, waters of the contiguous zone, other waters of the high seas subject to the NCP, and the land surface or land substrata, ground waters, and ambient air proximal to those waters. The term coastal zone delineates an area of Federal responsibility for response action. Precise boundaries are determined by U.S. EPA/USCG agreements and identified in Federal Regional Contingency Plans.

A wastewater collection system which conveys sanitary wastewaters (domestic, commercial and industrial wastewaters) and storm water through a single pipe to a publicly owned treatment works for treatment prior to discharge to surface waters.

A device for the catching and shredding of heavy solid matter in the primary stage of wastewater treatment.

A schedule of remedial measures included in a permit or an enforcement order, including a sequence of interim requirements such as actions, operations, or milestone events that lead to compliance with the CWA and regulations.

Either a flow or time-proportioned mixture of a certain number of discreet aliquots over a period of 24 hours.

Sample composed of two or more discrete samples. The aggregate sample will reflect the average water quality covering the compositing or sample period.

The natural biological decomposition of organic material in the presence of air to form a humus-like material.

A facility that confines a specific number of animals and meets certain other conditions in the regulations. Wastewater discharge permits for these operations are based upon the requirements of the CAFO Effluent Guidelines.

A space

(1) Is large enough and so configured that an employee can bodily enter and perform assigned work; and 

(2) Has limited or restricted means for entry or exit (for example, tanks, vessels, silos, storage bins, hoppers, vaults, and pits are spaces that may have limited means of entry.); and 

(3) Is not designed for continuous employee occupancy.

The POTW, if it has an approved pretreatment program; in the absence of such a program, the NPDES State, if it has an approved pretreatment program or EPA, if the State does not have an approved pretreatment program.

The U.S. Environmental Protection Agency publishes a list of four conventional pollutants: BOD, total suspended solids (TSS, nonfilterable), fecal coliform bacteria, oil and grease, and pH. See 40 CFR 401.16.

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

• The top of a dam, dike, spillway or weir, frequently restricted to the overflow portion.
• The summit of a wave or peak of a flood.

The numeric values and the narrative standards that represent contaminant concentrations that are not to be exceeded in the receiving environmental media (surface water, ground water, sediment) to protect beneficial uses.

The discharge of a pollutant measured during a calendar day or any 24-hourperiod that reasonably represents the calendar day for purposes of sampling. For pollutants with limitations expressed in units of mass, the "daily discharge" is calculated as the total mass of the pollutant discharged over the day. For pollutants with limitations expressed in other units of measurement, the "daily discharge" is calculated as the average measurement of the pollutant over the day.

The maximum allowable discharge of pollutant during a calendar day. Where daily maximum limitations are expressed in units of mass, the daily discharge is the total mass discharged over the course of the day. Where daily maximum limitations are expressed interms of a concentration, the daily discharge is the arithmetic average measurement of the pollutant concentration derived from all measurements taken that day.

Those uses specified in water quality standards for each water body or segment whether or not they are being attained.

A technique by which air under pressure is forced into sewage in an aeration tank. The air is pumped down into the sewage through a perforated pipe and bubbled through the sewage.

The decomposition of sludge that takes place in tanks and results in the partial gasification, liquefaction, and mineralization of pollutants.

The Regional Administrator or State Director, as the context requires, or an authorized representative. When there is no approved State program, and there is an EPA administered program, Director means the Regional Administrator. When there is an approved State program, “Director” normally means the State Director.

As defined by Section 311(a)(2) of CWA, includes, but is not limited to, any spilling, leaking, pumping, pouring, emitting, emptying, or dumping of oil, but excludes discharges in compliance with a permit under Section 402 of the CWA, discharges resulting from circumstances identified and reviewed and made a part of the public record with respect to a permit issued or modified under Section 402 of the CWA, and subject to a condition in such permit, or continuous or anticipated intermittent discharges from a point source, identified in a permit or permit application under Section 402 of the CWA, that are caused by events occurring within the scope of relevant operating or treatment systems. For purposes of the NCP, discharge also means substantial threat of discharge.

The form used (including any subsequent additions, revisions, or modifications) to report self-monitoring results by NPDES permittees. DMRs must be used by approved States as well as by EPA.

The heating the effluent and removing of the vapor or steam.

As defined by Section 101(7) of CERCLA, means any raw or finished water source that is or may be used by a public water system (as defined in the Safe Drinking Water Act, 42 U.S.C. et seq.) or as drinking water by one or more individuals.

Those areas of explicit economic importance to the public that due to their proximity to potential spill sources may require special protection and include, but are not limited to: public water supplies, publicly managed use areas, and Tribal use areas.

The liquid that comes out of a treatment plant after completion of the treatment process.

Any restriction established by the Administrator on quantities, rates, and concentrations of chemical, physical, biological and other constituents which are discharged from point sources, other than new sources, into navigable waters, the water of the contiguous zone or the ocean.

Title III Section 300. of SARA; created a system of State and local planning agencies for chemical emergencies and provided a way for communities to gain information about potential chemical hazards. EPCRA's mandates cover three main topics: emergency planning, emergency notification requirements, and requirements for reporting hazardous chemical inventories.

Areas identified as a priority for protection and special attention during cleanup in the event of a pollution incident. Designations of types of areas considered to be sensitive can be found in 1) the U.S. Fish and Wildlife Annex (Appendix IX) and 2) the Guidance for Facility and Vessel Response Plans Fish and Wildlife and Sensitive Environments, published by Department of Commerce/National Oceanic and Atmospheric Administration.

Removal of soil particles by wind and water. Often the eroded debris (silt or sediment) becomes a pollutant via stormwater runoff. Erosion occurs naturally but can be intensified by human activities such as farming, development, road-building, and timber harvesting.

A term used to describe the potential for soil to wash off disturbed, d evegetated earth into waterways during storms.

The process by which clumps of solids in sewage are made to increase in size by chemical, physical, or biological action.

A composite sample consisting of a mixture of aliquots collected at a constant time interval, where the volume of each aliquot is proportional to the flow rate of the discharge.

A specially shaped open channel flow section providing a change in the channel area and/or slope which results in an increased velocity and change in the level of the liquid flowing through the flume. A flume normally consists of three sections: (1) a converging section; (2) a throat section; and (3) a diverging section. The flow rate through the flume is a function of the liquid level at some point in the flume.

Small, non-chlorophyll bearing plants which may play a useful role in trickling filter

An NPDES permit issued under 40 CFR §122.28 that authorizes a category of discharges under the CWA within a geographical area. A general permit is not specifically tailored for an individual discharger .

A sample which is taken from a wastestream on a one-time basis without consideration of the flow rate of the wastestream and without consideration of time.

Domestic wastewater composed of washwater from sinks, kitchen sinks, bathroom sinks and tubs and laundry tubs.

A mechanical device which shreds solids and raises the fluid to a higher elevation through pressure sewers.

Underground water usually found in aquifers. Groundwater usually originates from infiltration. Wells tap the groundwater for water supply uses.

Any substance, other than oil, which, when discharged in any quantities into waters of the U.S., presents an imminent and substantial danger to the public health or welfare, including but not limited to fish, shellfish, wildlife, shorelines and beaches (Section 311 of the CWA); identified by EPA as the pollutants listed under 40 CFR Part 116.

Depth of flow.

Common everyday products that people use in and around their homes—including paint, paint thinner, herbicides, and pesticides—that, due to their chemical nature, can be hazardous if not properly disposed.

The burning of sludge or other material to remove the water and reduce the remaining residues to ash.

The introduction of pollutants into a municipal sewage treatment system from any nondomestic source (i.e., any industrial or commercial facility) regulated under Section 307(b), (c), or (d) of the CWA.

Water other than wastewater that enters a wastewater system and building sewers from the ground through such means as defective pipes, pipe joints, connections, and manholes.

The total quantity of water from both infiltration and inflow. Clean storm and/or groundwater that enters the sewer system through cracked pipes, leaky manholes, or improperly connected storm drains, down spouts and sump pumps. Most inflow comes from stormwater and most infiltration comes from groundwater. I/I affects the size of conveyance and treatment systems and, ultimately, the rate businesses and residents pay to operate and maintain them.

A land application technique where large volumes of wastewater are applied to land, allowed to penetrate the surface and percolate through the underlying soil.

A type of infiltration facility.

A type of infiltration facility.

Water other than wastewater that enters a wastewater system and building sewers from sources such as roof leaders, cellar drains, yard drains, area drains, foundation drains, drains from springs and swampy areas, manhole covers, cross connections between storm drains and sanitary sewers, catch basins, cooling towers, storm waters, surface runoff, street wash waters, and drainage. (Inflow does not include infiltration.)

Water, wastewater, or other liquid flowing into a reservoir, basin or treatment plant, or any unit thereof.

Waters of the United States in the inland zone, waters of the Great Lakes, and specified ports and harbors on inland rivers.

The environment inland of the coastal zone excluding the Great Lakes and specified ports and harbors on inland rivers. The term inland zone delineates an area of Federal responsibility for response action. Precise boundaries are determined by U.S. EPA/USCG agreements and identified in Federal regional contingency plans.

The maximum allowable concentration of a pollutant determined from the analysis of any discrete or composite sample collected, i ndependent of the flow rate and the duration of the sampling event.

A land application technique wherein wastewater is applied to the land to supply the water and nutrient needs of plants.

An area of land or an excavation in which wastes are placed for permanent disposal, and which is not a land application unit, surface impoundment, injection well, or waste pile.

A group of local representatives appointed by the State Emergency Response Commission (SERC) to prepare a comprehensive emergency plan for the local emergency planning district, as required by the Emergency Planning and Community Right-to-know Act (EPCRA), Title III Section 301(c) of SARA.

Conditional discharge limits imposed by municipalities upon industrial or commercial facilities that discharge to the municipal sewage treatment system.

Any NPDES facility or activity classified as such by the Regional Administrator, or in the case of approved State programs, the Regional Administrator in conjunction with the State Director. Major municipal dischargers include all facilities with design flows of greater than one million gallons per day and facilities with EPA/State approved industrial pretreatment programs. Major industrial facilities are determined based on specific ratings criteria developed by EPA/State.

A discharge limit that is measured in a mass unit such as pounds per day.

Practices used to limit the contact between significant materials and precipitation. These may include structural or nonstructural controls such as dikes, berms, sedimentation ponds, vegetation strips, spill response plans, etc.

A standard for water quality that applies to all MS4 operators regulated under the NPDES program. Since no precise definition of MEP exists, it allows for maximum flexibility on the part of MS4 operators as they develop and implement their programs to reduce the discharge of pollutants to the maximum extent practicable, including management practices, control techniques and system, design and engineering methods, and such other provisions as the Administrator or the State determines appropriate for the control of pollutants.

The injection of air into water via mechanical energy that causes the waste stream to absorb oxygen from the atmosphere.

Minute plant or animal life. Some microbes that may cause disease exist in sewage.

A unit of flow commonly used for wastewater discharges. One mgd is equivalent to 1.547 cubic feet per second.

A mixture of activated sludge and waters, containing organic matter undergoing activated sludge treatment in the aeration tank.

An area where an effluent discharge undergoes initial dilution and is extended to cover the secondary mixing in the ambient water body. A mixing zone is an allocated impact zone where water quality criteria can be exceeded as long as acutely toxic conditions are prevented.

A city, town, borough, county, parish, district, association, or other public body created by or under state law and having jurisdiction over disposal of sewage, industrial wastes, or other wastes, or an Indian tribe or an authorized Indian tribal organization, or a designated and approved management agency under section 208 of CWA.

A publicly owned conveyance or system of conveyances that discharges to waters of the US and is designed or used for collecting or conveying stormwater, is not a combined sewer, and is not part of a publicly owned treatment works (POTW).

The NCP provides nationwide organizational structure and procedures for responding to discharges of oil and releases of hazardous substances, pollutants and contaminants. In Executive Order (E.O.) 12777 (56 FR 54757, October 1991), the President delegated to the Environmental Protection Agency (EPA) the responsibility for the amendment of the NCP in coordination with members of the National Response Team (NRT) as well as the Federal Emergency Management Agency (FEMA) and the Nuclear Regulatory Commission to avoid inconsistent or duplicative requirements in the emergency planning responsibilities of those agencies.

It is a two-phased surface water quality program authorized by Congress as part of the 1987 Clean Water Act.  This is a national program for issuing, modifying, revoking and reissuing, terminating, monitoring and enforcing permits, and imposing and enforcing pretreatment requirements, under Sections 307, 318, 402, and 405 of CWA.

As defined by Section 7 of Executive Order 12777, the NPFC is the entity established by the Secretary of the Department of Transportation whose function is the administration of the Oil Spill Liability Trust Fund (OSLTF). This includes access to the OSLTF by Federal Agencies, States, and designated trustees for removal actions and initiation of natural resource damage assessments, as well as claims for removal costs and damages.

Any regulation promulgated by the EPA in accordance with Sections 307(b) and (c) of the CWA that applies to a specific category of industrial users and provides limitations on the introduction of pollutants into publicly owned treatment works.

Officials representing State, Tribal, Federal, and foreign governments who are authorized to act pursuant to section 107(f) of CERCLA, section 311(f)(5) of the CWA, or section 10006 of the OPA when there is injury or threat to natural resources, including their supporting ecosystems, as a result of a release of a hazardous substance or a discharge of oil. Natural resources means land, fish, wildlife, biota, air, water, ground water, drinking water supplies, and other such resources.

As defined by 40 CFR 110.1, the navigable waters includes: (a) All waters that are currently used, were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters that are subject to the ebb and flow of the tide;

(b) Interstate waters, including interstate wetlands;

(c) All other waters such as intrastate lakes, rivers, streams, mudflats, sandflats, and wetlands, the use, degradation, or destruction of which would affect or could affect interstate or foreign commerce including any such waters:

(1) That are or could be used by interstate or foreign travelers for recreational or other purposes;

(2) From which fish or shellfish are or could be taken and sold in interstate or foreign commerce;

(3) That are used or could be used for industrial purposes by industries in interstate commerce;

(d) All impoundments of waters otherwise defined as navigable waters under this Section;

(e) Tributaries of waters identified in (a) through (d) of this definition, including adjacent wetlands; and

(f) Wetlands adjacent to waters identified in (a) through (e) of this definition: Provided, that waste treatment systems (other than cooling ponds meeting the criteria of this paragraph) are not waters of the United States. Water of the United States do not include prior converted cropland. Notwithstanding the determination of an area's status as prior converted cropland by any other Federal Agency, for the purposes of the CWA, the final authority regarding CWA jurisdiction remains with U.S. EPA.

Any building, structure, facility, or installation from which there is or may be a “discharge of pollutants,” the construction of which commenced:

(a) After promulgation of standards of performance under section 306 of CWA which are applicable to such source, or

(b) After proposal of standards of performance in accordance with section 306 of CWA which are applicable to such source, but only if the standards are promulgated in accordance with section 306 within 120 days of their proposal.

Technology-based standards for facilities that qualify as new sources under 40 CFR §122.2 and 40 CFR §122.29. Standards consider that the new source facility has an opportunity to design operations to more effectively control pollutant discharges.

Wastes of animal or plant origin that contain a significant concentration of nitrogen.

A ll industrial materials and activities are protected by a storm resistant shelter to prevent exposure to rain, snow, snowmelt, and/or runoff. Industrial materials or activities include, but are not limited to, material handling equipment or activities, industrial machinery, raw materials, intermediate products, by-products, final products, or waste products.

One of the pollutant categories under the NPDES program. All pollutants that are not included in the list of conventional or toxic pollutants in 40 CFR Part 401. Non-conventional pollutants include parameters such as ammonia, nitrogen, phosphorus, chemical oxygen demand (COD), and whole effluent toxicity (WET).

Pollution that does not come from a single, identifiable source.  Nonpoint source pollution occurs when rainfall, snowmelt, or irrigation runs over land or through the ground, picks up pollutants, and deposits them into rivers, lakes, and coastal waters or introduces them into ground water. Nonpoint Sources include but are not limited to urban, agricultural, or industrial areas, roads, highways, construction sites, communities served by septic systems, recreational boating activities, timber harvesting, mining, livestock grazing, as well as physical changes to stream channels, and habitat degradation.

Non-storm water consists of all discharges to and from a storm water conveyance system that do not originate from precipitation events (i.e., all discharges from a conveyance system other than storm water).

A preventative action to protect receiving water quality that does not require construction. Nonstructural BMPs rely on behavioral changes in order to be effective. Major categories of non-structural BMPs include education, recycling, maintenance practices and source controls.  Examples of nonstructural BMPs are activity schedules, prohibitions of practices, street sweeping, facility maintenance, detection and elimination of illicit connections and illegal dumping, and other low-cost measures.

As defined in the Porter-Cologne Water Quality Control Act a nuisance is “anything which meets all of the following requirements: 1) Is injurious to health, or is indecent, or offensive to the senses, or an obstruction to the free use of property, so as to interfere with the comfortable enjoyment of life or property. 2) Affects at the same time an entire community or neighborhood, or any considerable number of persons, although the extent of the annoyance or damage inflicted upon individuals may be unequal. 3) Occurs during, or as a result of, the treatment or disposal of wastes.”

The typical method by which effluent limits are prescribed for pollutants in waste discharge requirements implementing the federal NPDES regulations. When numeric effluent limits are met at the “end-of-pipe,” the effluent discharge generally will not cause water quality standards to be exceeded in the receiving waters.

Elements or compounds essential as raw materials for organism growth and development (e.g., carbon, oxygen, nitrogen and phosphorous).

As defined by Section 311(a)(1) of CWA, means oil of any kind or in any form, including, but not limited to, petroleum, fuel oil, sludge, oil refuse, and oil mixed with wastes other than dredged spoil.

As defined by the NCP, means the fund established under Section 9509 of the Internal Revenue Code of 1986 (26 U.S.C. Section 9509).

As defined by the NCP, means the Federal official predesignated by U.S. EPA or USCG to coordinate and direct responses, or the government official designated by the lead agency to coordinate and direct removal actions under the NCP. In certain site-specific situations, DOD or DOE may also act as OSC.

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

An organism that is capable of producing an infection or disease in a susceptible host.

The maximum flow that occurs over a specific length of time (e.g. daily, hourly, instantaneous).

An authorization, license, or equivalent control document issued by EPA or an “approved State” to implement the requirements of this part and parts 123 and 124. “Permit” includes an NPDES “general permit” (40 CFR 122.28). Permit does not include any permit which has not yet been the subject of final agency action, such as a “draft permit” or a “proposed permit.”

A measure of the hydrogen ion concentration of water or wastewater.  It is a number denoting the common logarithm of the reciprocal of the hydrogen ion concentration. A pH of 7 is neutral. A pH less than 7 is acidic, and a pH greater than 7 is basic.

An element that while essential to life, contributes to the eutrophication of lakes and other bodies of water.

Any discernible, confined, and discrete conveyance, including but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, landfill leachate collection system, vessel or other floating craft from which pollutants are or may be discharged.

Dredged spoil, solid waste, incinerator residue, filter backwash, sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive materials (except those regulated under the Atomic Energy Act of 1954, as amended (42 U.S.C. 2011 et seq.)), heat, wrecked or discarded equipment, rock, sand, cellar dirt and industrial, municipal, and agricultural waste discharged into water.

Practices and processes that reduce or eliminate the generation of pollutants, in contrast to source control, treatment, or disposal.

Synthetic chemicals used to speed the removal of solids from sewage. The chemicals cause the solids to flocculate or clump together more rapidly than chemicals like alum or lime.

The lowest level that can be reliably achieved within specified limits of precision and accuracy during routine laboratory operating conditions.

Any form of rain or snow.

Treatment of waste stream before it is discharged to a collection system.

A physical procedure of removing the suspended solids and organic matter in a wastewater through sedimentation such as grit removal, screening for rags and debris, oil and grease removal, etc..

Those pollutants considered to be of principal importance for control under the CWA based on the NRDC consent decree settlement [( NRDC et al. v. Train, 8 E.R.C. 2120 (D.D.C. 1976), modified 12 E.R.C. 1833 (D.D.C. 1979)]; a list of these pollutants is provided as Appendix A to 40 CFR Part 423.

Any water which, during manufacturing or processing, comes into direct contact with, or results from the production or use of any raw material, intermediate product, finished product, byproduct, or waste product.

As defined by Section 212 of the CWA, A POTW is a  treatment works, that is owned by the State or municipality, including any devices and systems used in the storage, treatment, recycling, and reclamation of municipal sewage or industrial wastes of a liquid nature and sewers, pipes, and other conveyances only if they convey wastewater to a POTW treatment plant [40 CFR §403.3].

Individual having full authority, including contracting authority, to implement spill removal actions. (See 40 CFR 112.20(h)(1)).

The Waters of the U.S. which includes both surface and groundwaters.

Annual amount of rainfall which contributes to groundwater as a function of hydrologic soil group.

Any MS4 covered by the NPDES program (regulated small, medium, or large MS4s).

The modification of stormwater management systems through the construction and/or enhancement of wet ponds, wetland plantings, or other BMPs designed to improve water quality.

The RCP is the mechanism for planning and coordinating regional preparedness and response actions for discharges of oil and releases of hazardous substances under the auspices of the Regional Response Team (RRT).

The RRT consists of a representative from each State in the region and representatives from 15 Federal Agencies. It is an regional response organization which acts as a regional body responsible for regional planning and coordination of preparedness and response actions involving oil and hazardous materials.  The RRT coordinates assistance and advice to the OSC in the event of a major or substantial spill.

Filters that physically remove some suspended solids from sewage. Air and bacteria decompose additional wastes filtering through the sand. Cleaner water drains from the bed. The sludge accumulating at the surface must be removed from the bed periodically.

A system of underground pipes that carries sanitary waste or process wastewater from homes, businesses, and industries to the POTW.

Untreated or partially treated sewage overflows from a sanitary sewer collection system.

A combination of physical and biological processes that is used to remove/treat pollutants in municipal sewage.  It is a technology-based requirements for direct discharging municipal sewage treatment facilities. Standards are expressed as a minimum level of effluent quality in terms of: BOD5, suspended solids (SS), and pH.

The process of depositing soil particles, clays, sands, or other sediments that were picked up by runoff.

Tanks that help to remove solids from sewage. The wastewater is pumped to the tanks where the solids settle to the bottom or float on the top as scum. The scum is skimmed off the top, and solids on the bottom are pumped to incineration, digestion, filtration or other means of final disposal.

The slow movement of water through small cracks or pores of a material, through the soil, or into or out of a body of surface or subsurface water.

Underground tanks where domestic wastes are piped to directly from a home or homes when a sewer line is not available to carry them to a treatment plant. The bacteria in the wastes decompose the organic waste and the sludge settles on the bottom of the tank. The effluent flows out of the tank into the ground through drains. The sludge is pumped out of the tanks, usually by commercial firms, at regular intervals.

Solid, semi-solid, or liquid residue generated during the treatment of domestic sewage in a treatment works [40 CFR §503.9(w)]. Sewage sludge includes, but is not limited to, domestic septage; scum or solids removed in primary, secondary, or advanced wastewater treatment processes; and a material derived from sewage sludge. Sewage sludge does not include ash generated during the firing of sewage sludge in a sewage sludge incinerator or grit and screenings generated during preliminary treatment of domestic sewage in a treatment works.

The volume, concentrations, or mass of a pollutant in stormwater discharge that can cause or threaten to cause pollution, contamination, or nuisance that adversely impact human health or the environment and cause or contribute to a violation of any applicable water quality standards for receiving water.

The solid matter that settles to the bottom, floats, or becomes suspended in sedimentation tanks and must be disposed of by filtration and incineration or by transport to appropriate disposal sites.

A plan prepared by a facility to minimize the likelihood of a spill and to expedite control and cleanup activities should a spill occur.

A code number system used to identify various types of industries. The code numbers are published by the Superintendent o Documents, U.S. Government Printing Office, Washington, D.C. 20402. A particular industry may have more than one SIC code if it conducts several types of commercial or manufacturing activities onsite.

The destruction of all living organisms. In contrast, disinfection is the destruction of most of the living organisms.

A separate system of pipes that carries only runoffs from buildings and land during a storm.

Precipitation that accumulates in natural and/or constructed storage and stormwater systems during and immediately following  rainfall and snow storm events.  Most storm water discharges are required to have coverage by an NPDES permit.

Physical facilities or controls which may include secondary containment, treatment measures, (e.g. first flush diversion,detention/retention basins, and oil/grease separators), run-off controls (e.g., grass swales, infiltration trenches/basins, etc.), and engineering and design modification of existing structures.

A mechanism used for removing water or wastewater from a sump or wet well.

The small particles of solid pollutants which are present in sewage and which resist separation from the water by conventional means.

A permit limit for a pollutant that is based on the capability of a treatment method to reduce the pollutant to a certain concentration.

A composite sample prepared by collecting fixed volume aliquots at specified time intervals, which are combined into a single sample for analysis.

The total dissolved (filterable) solids as determined by use of the method specified in 40 CFR part 136.

The maximum amount of a pollutant that can be discharged into a water body from all sources (point and non-point) and still maintain water quality standards. TMDLs were established by the 1972 Clean Water Act. Under Clean Water Act Section 303(d), TMDLs must be developed for all water bodies that do not meet water quality standards after application of technology-based controls.

The total amount of particulate matter that is suspended in the water column as determined by the method specified in 40 CFR Part 136.

One of the pollutant categories under the NPDES program. Toxic pollutants are also called as priority pollutants include metals and manmade organic compounds. Toxic pollutants include those pollutants listed by the Administrator under CWA Section 307(a)(1) or any pollutant listed under Section 405(d) which relates to sludge management.

A site-specific study conducted in a stepwise process designed to identify the causative agent(s) of effluent toxicity, isolate the sources of toxicity, evaluate the effectiveness of toxicity control options, and then confirm the reduction in effluent toxicity.

A procedure to determine the toxicity of a chemical or an effluent using living organisms. A toxicity test measures the degree of effect on exposed test organisms of a specific chemical or effluent.

A group of officials appointed by Native American governing bodies to implement the provisions of Title III of SARA.

A support media for bacterial growth, usually a bed of rocks or stones. The sewage is trickled over the bed so the bacteria can break down the organic wastes.

An exceptional incident in which there is unintentional and temporary noncompliance with the permit limit because of factors beyond the reasonable control of the permittee. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation.

Stormwater from urban areas, which tends to contain heavy concentrations of pollutants from urban activities.

Any oil that has been refined from crude oil, or any synthetic oil, that has been used and as a result of such use is contaminated by physical or chemical impurities.

Any mechanism or provision under Sections 301 or 316 of the CWA or under 40 CFR Part 125, or in the applicable “effluent limitations guidelines” which allows modification to or waiver of the generally applicable effluent limitations requirements or time deadlines of the CWA. This includes provisions which allow the establishment of alternative limitations based on fundamentally different factors.

Waste oil is any oil that has been refined from crude oil, or any synthetic oil, that has been physically or chemically contaminated as a result of a spill.

A series of tanks, screens, filters, and other processes by which pollutants are removed from water.

The proportion of a receiving water’s total maximum daily load that is allocated to one of its existing or future point sources of pollution.

A value determined by selecting the most stringent of the effluent limits calculated using all applicable water quality criteria (e.g., aquatic life, human health, and wildlife) for a specific point source to a specific receiving water for a given pollutant.

A law or regulation that consists of the beneficial use or uses of a water body, the numeric and narrative water quality criteria that are necessary to protect the use or uses of that particular water body, and an antidegradation statement.

All waters that are currently used, were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters subject to the ebb and flow of the tide. Waters of the United States include but are not limited to all interstate waters and intrastate lakes, rivers, streams (including intermittent streams), mudflats, sand flats, wetlands, sloughs, prairie potholes, wet meadows, play lakes, or natural ponds. [See 40 CFR §122.2 for the complete definition.]

A device used to gauge the flow rate of liquid through a channel; is essentially a dam built across an open channel over which the liquid flows, usually through some type of notch.

Water entering storm drains during rainstorms/wet weather events.

Those areas that are inundated or saturated by surface or groundwater at a frequency or duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include playa lakes, swamps, marshes, bogs, and similar areas such as sloughs, prairie potholes, wet meadows, prairie river overflows, mudflats, and natural ponds.

The total toxic effect of an effluent measured directly with a toxicity test.