Learn about Effluent Guidelines
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Effluent Guidelines are national wastewater discharge standards that are developed by the EPA on an industry-by-industry basis. These are technology-based regulationsA regulation based on the performance of wastewater treatment and control technologies. The discharge standards are developed independently of the potential impact of a discharge on the receiving water body. (Impacts on specific receiving waters are addressed through other Clean Water Act mechanisms: Water Quality Standards and water quality-based effluent limitations in individual permits)., and are intended to represent the greatest pollutant reductions that are economically achievable for an industry. The standards for direct dischargersA point source that discharges pollutants to waters of the United States, such as streams, lakes, or oceans. are incorporated into National Pollutant Discharge Elimination System (NPDES) permits issued by States and EPA regional offices, and permits or other control mechanisms for indirect dischargersA facility that discharges pollutants to a publicly owned treatment works (municipal sewage treatment plant). (refer to Pretreatment Program).
On this page:
- Development of Effluent Guidelines
- Pollutant Types
- Levels of Control
- Analytical Methods
- Effluent Guidelines Program Plans
- Implementation
- Industries and/or Pollutants not Specifically Regulated by Effluent Guidelines
Development of Effluent Guidelines
- industry practices
- characteristics of discharges (e.g., pollutants, flow variability, stormwater)
- technologies or practices used to prevent or treat the discharge
- economic characteristics
The EPA identifies the best available technology that is economically achievable for that industry and sets regulatory requirements based on the performance of that technology. The Effluent Guidelines do not require facilities to install the particular technology identified by the EPA; however, the regulations do require facilities to achieve the regulatory standards which were developed based on a particular model technology.
Pollutant Types
Clean Water Act (CWA) section 304(a)(4) designates the following as "conventional" pollutants: biochemical oxygen demand (BOD5), total suspended solids (TSS), fecal coliform, pH, and any additional pollutants the EPA defines as conventional. The Agency designated "oil and grease" as an additional conventional pollutant on July 30, 1979 (refer to 44 FR 44501).
Levels of Control
National regulations for industrial wastewater discharges set technology-based numeric limitations for specific pollutants at several levels of control: BPT, BAT, BCT, NSPS, PSNS or PSES. Each of these terms is defined below. Effluent limitations are based on performance of specific technologies, but the regulations do not require use of a specific control technology.
Type of Sites Regulated | BPT | BCT | BAT | NSPS | PSES | PSNS |
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Existing Direct Dischargers | • | • | • | |||
New Direct Dischargers | • | |||||
Existing Indirect Dischargers | • | |||||
New Indirect Dischargers | • |
Pollutants Regulated | BPT | BCT | BAT | NSPS | PSES | PSNS |
---|---|---|---|---|---|---|
Priority Pollutants | • | • | • | • | • | |
Conventional Pollutants | • | • | • | |||
Nonconventional Pollutants | • | • | • | • | • |
BPT
Best Practicable Control Technology Currently Available is defined at CWA section 304(b)(1). In specifying BPT, the EPA looks at a number of factors:
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the total cost of applying the control technology in relation to the effluent reduction benefits
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age of the equipment and facilities
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processes employed by the industry and any required process changes
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engineering aspects of the control technologies
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non-water quality environmental impacts, including energy requirements
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other factors as the EPA deems appropriate
Traditionally, the EPA establishes BPT effluent limitations based on the average of the best performance of facilities within the industry of various ages, sizes, processes or other common characteristics. Where existing performance is uniformly inadequate, BPT may reflect higher levels of control than currently in place in an industrial category if the Agency determines that the technology can be practically applied.
BCT
Best Conventional Pollutant Control Technology, defined at CWA section 304(b)(4), addresses conventional pollutants from existing industrial point sources. In addition to considering the other factors specified in section 304(b)(4)(B), the EPA establishes BCT limitations after consideration of a two part "cost-reasonableness" test. The initial BCT methodology and some BCT effluent limitations were published in 1979. A revised methodology, with additional effluent limitations, and some revised limitations, were published in 1986.
1986 Amendment
- Final rule (July 9, 1986)
- Proposed rule (October 29, 1982)
1979 Initial Rulemaking
- Final rule (August 29, 1979)
- Proposed rule (August 23, 1978)
BAT
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cost of achieving BAT effluent reductions
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age of equipment and facilities involved
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the processes employed by the industry and potential process changes
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non-water quality environmental impacts, including energy requirements
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other factors as the EPA deems appropriate
NSPS
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Definition of "new source" for direct dischargers: 40 CFR 122.2, 122.29
PSNS
Pretreatment Standards for New Sources is defined at CWA section 307(c). PSNS are national, uniform, technology-based standards that apply to dischargers to publicly owned treatment worksA treatment works that is owned by the state or municipality. (POTWs) from specific industrial categories (i.e., indirect dischargers). They are designed to prevent the discharges of pollutants that pass through, interfere with, or are otherwise incompatible with the operation of POTWs. PSNS are to be issued at the same time as NSPS. The Agency considers the same factors in promulgating PSNS as it considers in promulgating NSPS.
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Definition of "new source" for indirect dischargers: 40 CFR 403.3(m)
PSES
Pretreatment Standards for Existing Sources is defined at CWA section 307(b). Like PSNS, PSES are national, uniform, technology-based standards that apply to indirect dischargers. They are designed to prevent the discharge of pollutants that pass through, interfere with, or are otherwise incompatible with the operation of POTWs.
Dischargers subject to PSES are required to comply with those standards by a specified date, typically no more than three years after the effective date of the categorical standard.
BMPs
Best Management Practices are defined as a permit condition used in place of, or in conjunction with effluent limitations, to prevent or control the discharge of pollutants. BMPs may include a schedule of activities, prohibition of practices, maintenance procedure, or other management practice.
- Direct dischargers: 40 CFR 122.2, 40 CFR 122.44(k)
- Indirect dischargers: 40 CFR 403.3(e)
CWA section 304(e) authorizes the EPA to include BMPs in Effluent Guidelines for certain toxic or hazardous pollutants for the purpose of controlling "plant site runoff, spillage or leaks, sludge or waste disposal, and drainage from raw material storage." CWA section 402(a)(1) and 40 CFR 122.44(k) also provide for BMPs to control or abate the discharge of pollutants when numeric limitations and standards are infeasible.
Analytical Methods
Effluent Guidelines Program Plans
CWA section 304(b) requires the EPA to annually review and, if appropriate, revise Effluent Guidelines. The EPA publishes a plan every other year, establishing a schedule for annual review and revision, pursuant to section 304(m). This plan also identifies industries discharging more than trivial amounts of toxic or nonconventional pollutants, such as nutrients, for which the Agency has not yet promulgated Effluent Guidelines. The EPA is required to establish a schedule for completing Effluent Guidelines for these industries within three years, and the Agency must take public comment on its proposed plan prior to issuing a final plan. The plan announces any EPA decisions to proceed with rulemakings which may lead to new requirements for direct discharging facilities covered by existing Effluent Guidelines.
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Refer to Effluent Guidelines Plan for more details
Implementation
Effluent Guidelines are implemented through the NPDES Permit Program. Direct dischargers are regulated by permits that specify limits using BPT, BAT, BCT and NSPS.
Pretreatment standards are implemented through the National Pretreatment Program. Indirect dischargers are regulated through categorical standards issued based on PSNS and PSES.
Industries and/or Pollutants not Specifically Regulated by Effluent Guidelines
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Refer to Chapter 5 ("Technology-Based Effluent Limitations") of the NPDES Permit Writers' Manual
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Refer to the Local Limits Development Guidance