Pretreatment standards

Scope

The National Pretreatment Program requires all large POTWs (those designed to treat flows of more than 5 million gallons per day) and smaller POTWs (that accept wastewater from IUs that could affect the treatment plant or its discharges) to establish local pretreatment programs. These local programs must enforce all national pretreatment standards and requirements in addition to any more stringent local requirements necessary to protect site-specific conditions at the POTW.

Regulatory citations

• 40 CFR 403 — General pretreatment regulations for existing and new sources of pollution
• 40 CFR 405 to 471 — Categorical pretreatment standards

Key definitions

• State water pollution control agency, interstate agency, State, municipality, person, territorial seas, contiguous zone, biological monitoring, and schedule of compliance: Shall be defined in accordance with section 502 of the Act unless the context otherwise requires.
• Act: Federal Water Pollution Control Act, also known as the Clean Water Act, as amended, 33 U.S.C. 1251, et seq.
• Approval authority: The Director in an NPDES State with an approved State pretreatment program and the appropriate Regional Administrator in a non-NPDES State or NPDES State without an approved State pretreatment program.
• Approved POTW Pretreatment Program or Program or POTW Pretreatment Program: A program administered by a POTW that meets the criteria established in this regulation (403.8 and 403.9) and which has been approved by a Regional Administrator or State Director in accordance with 403.11 of this regulation.
• Best Management Practices (BMPs): Schedules of activities, prohibitions of practices, maintenance procedures, and other management practices to implement the prohibitions listed in 403.5(a)(1) and (b). BMPs also include treatment requirements, operating procedures, and practices to control plant site runoff, spillage or leaks, sludge or waste disposal, or drainage from raw materials storage.
• Blowdown: The minimum discharge of recirculating water for the purpose of discharging materials contained in the water, the further buildup of which would cause concentration in amounts exceeding limits established by best engineering practice.
• Control authority: Refers to: (1) The POTW if the POTW’s Pretreatment Program Submission has been approved in accordance with the requirements of 403.11; or (2) The Approval Authority if the Submission has not been approved.
• Discharge of pollutant(s): (1) The addition of any pollutant to navigable waters from any point source and (2) any addition of any pollutant to the waters of the contiguous zone or the ocean from any point source, other than from a vessel or other floating craft. The term “discharge” includes either the discharge of a single pollutant or the discharge of multiple pollutants.
• Effluent limitation: 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 waters of the contiguous zone or the ocean.
• Effluent limitations guidelines: Any effluent limitations guidelines issued by the Administrator pursuant to section 304(b) of the Act.
• Indirect discharge or Discharge: The introduction of pollutants into a POTW from any non-domestic source regulated under section 307(b), (c) or (d) of the Act.
• Industrial user or User: A source of Indirect Discharge.
• Interference: A Discharge which, alone or in conjunction with a discharge or discharges from other sources, both: (1) Inhibits or disrupts the POTW, its treatment processes or operations, or its sludge processes, use or disposal; and (2) Therefore is a cause of a violation of any requirement of the POTW’s NPDES permit (including an increase in the magnitude or duration of a violation) or of the prevention of sewage sludge use or disposal in compliance with the following statutory provisions and regulations or permits issued thereunder (or more stringent State or local regulations): Section 405 of the Clean Water Act, the Solid Waste Disposal Act (SWDA) (including title II, more commonly referred to as the Resource Conservation and Recovery Act (RCRA), and including State regulations contained in any State sludge management plan prepared pursuant to subtitle D of the SWDA), the Clean Air Act, the Toxic Substances Control Act, and the Marine Protection, Research and Sanctuaries Act.
• Navigable waters: “Waters of the United States, including the territorial seas,” as defined in 120.2 of this chapter.
• New source: See 40 CFR 403.3.
• Noncontract cooling water: Water used for cooling which does not come into direct contact with any raw material, intermediate product, waste product or finished product.
• Noncontact cooling water pollutants: Pollutants present in noncontact cooling waters.
• NPDES permit or Permit: A permit issued to a POTW pursuant to section 402 of the Act.
• Pass through: A Discharge which exits the POTW into waters of the United States in quantities or concentrations which, alone or in conjunction with a discharge or discharges from other sources, is a cause of a violation of any requirement of the POTW’s NPDES permit (including an increase in the magnitude or duration of a violation).
• Point source: 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, or vessel or other floating craft, from which pollutants are or may be discharged.
• Pollutant: Dredged spoil, solid waste, incinerator residue, sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand, cellar dirt and industrial, municipal and agricultural waste discharged into water. It does not mean (1) sewage from vessels or (2) water, gas or other material which is injected into a well to facilitate production of oil or gas, or water derived in association with oil or gas production and disposed of in a well, if the well, used either to facilitate production or for disposal purposes, is approved by authority of the State in which the well is located, and if such State determines that such injection or disposal will not result in degradation of ground or surface water resources.
• Pollution: The man-made or man induced alteration of the chemical, physical, biological and radiological integrity of water.
• POTW Treatment Plant: That portion of the POTW which is designed to provide treatment (including recycling and reclamation) of municipal sewage and industrial waste.
• Pretreatment: The reduction of the amount of pollutants, the elimination of pollutants, or the alteration of the nature of pollutant properties in wastewater prior to or in lieu of discharging or otherwise introducing such pollutants into a POTW. The reduction or alteration may be obtained by physical, chemical or biological processes, process changes or by other means, except as prohibited by 403.6(d). Appropriate pretreatment technology includes control equipment, such as equalization tanks or facilities, for protection against surges or slug loadings that might interfere with or otherwise be incompatible with the POTW. However, where wastewater from a regulated process is mixed in an equalization facility with unregulated wastewater or with wastewater from another regulated process, the effluent from the equalization facility must meet an adjusted pretreatment limit calculated in accordance with 403.6(e).
• Pretreatment requirements: Any substantive or procedural requirement related to Pretreatment, other than a National Pretreatment Standard, imposed on an Industrial User.
• Process waste water: 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, by-product, or waste product.
• Process waste water pollutants: Pollutants present in process waste water.
• Publicly Owned Treatment Works (POTW): A treatment works as defined by section 212 of the Act, which is owned by a State or municipality (as defined by section 502(4) of the Act). This definition includes any devices and systems used in the storage, treatment, recycling and reclamation of municipal sewage or industrial wastes of a liquid nature. It also includes sewers, pipes and other conveyances only if they convey wastewater to a POTW Treatment Plant. The term also means the municipality as defined in section 502(4) of the Act, which has jurisdiction over the Indirect Discharges to and the discharges from such a treatment works.
• Significant Industrial User (SIU): See 40 CFR 403.3.
• Standard of performance: Any restriction established by the Administrator pursuant to section 306 of the Act on quantities, rates, and concentrations of chemical, physical, biological, and other constituents which are or may be discharged from new sources into navigable waters, the waters of the contiguous zone or the ocean.
• The following abbreviations shall have the following meanings:
  • BOD5 means five-day biochemical oxygen demand;
  • COD means chemical oxygen demand;
  • TOC means total organic carbon;
  • TDS means total dissolved solids;
  • TSS means total suspended non-filterable solids;
  • kw means kilowatt(s);
  • kwh means kilowatt hour(s);
  • Mw means megawatt(s);
  • Mwh means megawatt hour(s);
  • hp means horsepower;
  • mm means millimeter(s);
  • cm means centimeter;
  • m means meter(s);
  • in means inch;
  • ft means foot (feet);
  • l means liter(s);
  • cu m means cubic meter(s);
  • k cu m means 1000 cubic meter(s);
  • gal means gallon(s);
  • cu ft means cubic foot (feet);
  • mg means milligram(s);
  • g means gram(s);
  • kg means kilogram(s);
  • kkg means 1000 kilogram(s);
  • lb means pound(s);
  • sq m means square meter(s);
  • ha means hectare(s);
  • sq ft means square foot (feet); and
  • ac means acre(s).

Summary of requirements

Types of national pretreatment standards. There are three types of national pretreatment requirements:

• Prohibited discharge standards. All IUs, regardless of whether they are subject to any other national, state, or local pretreatment requirements, are subject to the general and specific prohibitions identified in 40 CFR 403.5(a) and (b), respectively.
• Categorical pretreatment standards. Standards specifying the quantity, concentration, or pollutant properties of pollutants that may be discharged to POTWs. EPA promulgates pretreatment standards for specific industry categories. These standards are codified in 40 CFR 405 to 471.
• Local limits. Specific discharge limits developed and enforced by POTWs upon IUs to implement the general and specific discharge prohibitions listed in 40 CFR 403.5(a)(1) and (b).

• Interference. A discharge that causes interference inhibits or disrupts the POTW, its treatment processes or operations, or its sludge processes, use, or disposal and therefore causes a violation of any requirement of the POTW’s NPDES permit.
• Pass through. Some pollutants are not amenable to biological wastewater treatment at POTWs and can pass through the treatment plant untreated. This pass through of pollutants affects the receiving water and might cause fish kills or other deleterious effects.

Approval authorities.

• Determine when and where POTW pretreatment programs need to be developed,
• Set schedules and specific requirements for POTWs to develop pretreatment programs by including appropriate conditions in POTW NPDES permits or other applicable control mechanisms,
• Review and approve requests for new or modified POTW pretreatment programs,
• Provide technical guidance to control authorities,
• Review and approve requests for site-specific variances to categorical pretreatment standards,
• Review and receive control authority annual pretreatment reports,
• Evaluate POTW pretreatment program implementation by conducting pretreatment compliance audits and inspections, and
• Initiate enforcement actions against noncompliant POTWs or industries as appropriate.

• Develop legal authority for their jurisdiction, local limits, standard operating procedures, and an enforcement response plan to establish and maintain an approved pretreatment program.
• Regulate IUs by:
  • Issuing control mechanisms,
  • Conducting monitoring and inspections,
  • Receiving and reviewing reports and notifications,
  • Reviewing requests for net/gross variances,
  • Evaluating compliance with program requirements, and
  • Taking enforcement as appropriate.
• Submit regular reports to approval authorities to describe the implementation of their pretreatment program.
• Administer and enforce pretreatment standards and requirements. The control authority’s primary goals are to:
  • Prevent the discharge of pollutants into the publicly owned treatment works (POTW) that would result in interference and pass at the POTW’s wastewater treatment plant (WWTP); and
  • Ensure that IUs comply with all applicable pretreatment program requirements.

Requirements for all IUs. All IUs are responsible for notifying the receiving POTW and/or control authority (if they are different entities) about the following discharges or changes to existing discharge practices:

• Changes affecting potential for slug discharge (40 CFR 403.8(f)(2)(vi)).
• Potential problems, including slug loadings (40 CFR 403.12(f)).
• Noncompliance and repeat sampling report (40 CFR 403.12(g)(2)).
• Changed discharge (40 CFR 403.12(j)).
• Changed production (for IUs with limits calculated from a production-based standard) (40 CFR 403.6(c)(9)).
• Hazardous wastes discharge (40 CFR 403.12(p)). See also Hazardous Waste Reporting Requirements for Industrial Users under 40 CFR 403.12(p) and (j).
• Bypass (40 CFR 403.17).

These notifications alert the POTW and/or control authority to discharges that can affect the collection system or treatment plant. In addition, the control authority may specifically require its IUs to:

• Submit reports, as required (40 CFR 403.12).
• Maintain records of pretreatment activities, as required (40 CFR 403.12(o)).

• Is subject to categorical pretreatment standards (CIUs) under 40 CFR 403.6 and 40 CFR Chapter I, Subchapter N, except those designated as NSCIUs; or
• Discharges an average of 25,000 gallons per day or more of process wastewater to the POTW (excluding sanitary, noncontact cooling, and boiler blowdown wastewater); or
• Contributes a process wastestream that makes up five percent or more of the average dry-weather hydraulic or organic capacity of the POTW treatment plant; or
• Is designated as such by the POTW on the basis that the IU has a reasonable potential for adversely affecting the POTW’s operation or for violating any pretreatment standard or requirement (in accordance with 40 CFR 403.8(f)(6)).

• Conduct required self-monitoring and submit periodic compliance reports every six months according to the reporting requirements for IUs not subject to categorical pretreatment standards (40 CFR 403.12(h)).
  • Ensure that self-monitoring meets applicable sample collection and analysis requirements (40 CFR 403.12(g)).
  • Ensure that reports meet applicable signatory and certification requirements (40 CFR 403.12(l)).
• Develop and implement a slug control plan, if required by the control authority (40 CFR 403.8(f)(2)(vi)).

Non-domestic dischargers subject to these national standards are called categorical industrial users (CUIs). CIUs must comply with additional requirements in the federal regulations that include, but are not limited to, the following:

• Submit to its control authority:
  • A baseline monitoring report (40 CFR 403.12(b)(1-7),
  • Compliance schedule progress reports (40 CFR 403.12(c)(1–3)),
  • A 90-day compliance report (40 CFR 403.12(d)), and
  • A periodic compliance report (40 CFR 403.12(e)) (This requirement is the CIU equivalent to the SIUs reports required at 40 CFR 403.12(h)).
• Notify the POTW and/or control authority of upset (40 CFR 403.16).

Additional requirements might apply if the CIU’s control authority implements optional pretreatment program provisions. The requirements should be specified in the CIU’s control mechanism. The CIU must notify its POTW and/or control authority (if they are different entities) about the following:

• Production level change in the equivalent limit calculation (40 CFR 403.6(c)(5)).
• Material/significant change in the alternative limit calculation (40 CFR 403.6(e)).
• Waived pollutant present (40 CFR 403.12(e)(2)(vi)).
• Middle-tiered categorical industrial user (40 CFR 403.12(e)(3)(iv)).