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EPA Seeks to Address PFAS Discharges Using NPDES Permits

Kirk O'Reilly and William L Goodfellow Jr


  • Discusses how the EPA seeks to use the National Pollutant Discharge Elimination System to reduce discharges of wastewater containing per- and polyfluoroalkyl substances.
  • Analyzes the December 2022 memorandum to further develop water quality criteria for PFAS.
EPA Seeks to Address PFAS Discharges Using NPDES Permits
Bim via Getty Images

The U.S. Environmental Protection Agency (EPA) seeks to use the National Pollutant Discharge Elimination System (NPDES) to reduce discharges of wastewater containing per- and polyfluoroalkyl substances (PFAS). On December 5, 2022, EPA released a memorandum titled “Addressing PFAS Discharges in NPDES Permits and Through the Pretreatment Program and Monitoring Programs.” This guidance focuses on steps permit writers can implement under existing authorities at NPDES-permitted facilities where PFAS is expected or likely to be present in the discharge. EPA recommends an array of NPDES provisions and programs that should be implemented to the fullest extent available under state and local law. Each recommendation includes citations to regulations that provide the appropriate authority. So, unlike typical regulatory guidance, it may impose requirements without the need for additional notice and comment. 

While the December 2022 memorandum reiterates the EPA’s goal to revise effluent limitation guidelines (ELG) and further develop water quality criteria for PFAS, it also outlines specific actions that states and EPA Regions should implement with regard to new and reissued NPDES permits and pretreatment requirements. EPA seeks to cooperate with state-authorized permitting authorities, or within the regions when states are not authorized, to leverage the NPDES program to control the discharge of PFAS. The program will enable EPA and the states to obtain information on the sources and quantities of PFAS in wastewater discharges through the permit application and discharge monitoring report (DMR) process. Using these additional data, EPA plans the development of appropriate next steps to limit further discharges of PFAS. Implementation at specific sites may occur when issuing new permits or modifying existing ones.

Facilities covered by the guidance are applicable industrial direct dischargers and publicly owned treatment works (POTW). Implementation may also affect facilities that discharge to POTWs. Industrial users (IU) in specific categories identified as applicable direct discharges include organic chemicals, plastics and synthetic fibers, metal finishing, electroplating, electric and electronic components, landfills, pulp and paper, leather tanning, plastics molding, textile mills, paint formulating, and airports. Other discharges may include remediation sites and military installations. POTWs will be required to update their IU inventory to better understand potential PFAS sources.

The memorandum recommends quarterly monitoring of effluent and wastewater residuals for each of the 40 PFAS parameters detectable by Draft Method 1633. However, Draft Adsorbable Organic Fluorine Method 1621 can be used in conjunction with Draft Method 1633. All PFAS monitoring data must be reported on DMRs. It also recommends that facilities generating PFAS-contaminated solid waste or air emissions not covered by NPDES permitting coordinate with appropriate state authorities on proper containment and disposal to avoid cross-media contamination.

EPA requests that permit writers require the implementation of best management practices (BMP) focused on pollution prevention and source reduction. Actions may include eliminating PFAS-containing products, optimizing operations, and improving housekeeping practices to minimize accidental discharges. At sites that use PFAS-containing aqueous film forming foam (AFFF) for firefighting, industrial-stormwater permits may prohibit the uses of the foam in training, require immediate cleanup following use or accidental release of foam, or eliminate the use of specific AFFF products. EPA also expands the public notice requirements for draft NPDES permits to include notification of public water systems with intakes downstream of potential PFAS discharges.

As required under the Clean Water Act section 301(b), technology-based treatment represents the minimum level of control that must be imposed under a NPDES permit. Site-specific, technology-based effluent limits for PFAS discharges developed using best-professional judgment may be appropriate for facilities in the absence of approved effluent guidelines. NPDES permits must include water quality–based effluent limits when necessary to achieve state or local water quality standards. If a state has established a numeric criterion or a numeric translation of an existing narrative water quality standard for PFAS parameters, permit writers should apply that numeric criterion or narrative interpretation in permitting decisions. Water quality objectives and effluent limits continue to be developed at the state and federal level.

EPA guidance applies to POTWs even if they do not receive significant industrial discharges. Recommendations include increased monitoring of influent, effluent, and biosolids and implementing PFAS pretreatment programs. Monitoring requirements are consistent with those recommended for industrial discharges. EPA instructs that permits require POTW operators to identify IUs that might be subject to the PFAS pretreatment program and estimate the quantity of pollutants discharged by each. To the extent possible, POTWs and states may use their available authorities to monitor the IUs quarterly and develop local limits that require IUs to implement BMPs. In the absence of local limits or the authority to issue IU control mechanisms, state pretreatment coordinators are encouraged to work with the POTWs to encourage pollution prevention, product substitution, and good housekeeping practices to reduce upstream sources of PFAS.

Implications of EPA’s guidance will evolve as agencies integrate these recommendations into new NPDES discharge permits or during the permit renewal process.