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Metropolitan Water Reclamation District of Greater Chicago

Per- and polyfluoroalkyl substances (PFAS) are a group of manmade fluorinated compounds that have been in commercial use since the 1940s and are abundant in consumer products. PFAS are found in every American household and were designed by scientists not to break down, which is why they are often called “forever chemicals.”

PFAS are in countless commercial, consumer, and industrial products and are acknowledged by the U.S. Environmental Protection Agency (EPA) to be widely present in the environment.  Historical uses include firefighting foams, food packaging, carpet, personal care products, and cleaning products. They are also used by many industries such as plating, tanneries, and clothing and in equipment fluids such as engine oil, hydraulic fluids, brake fluids, and lubricants. Two of the most studied chemicals, perfluorooctanoic acid (PFOA) and perfluorooctanoic sulfonate (PFOS), were voluntarily phased out by industry over the past decade but may still persistent at locations where they were used or introduced into the environment.

PFAS may enter wastewater treatment plants after being discharged from industrial, commercial and household sources. The Metropolitan Water Reclamation District of Greater Chicago (MWRD) is committed to working closely with federal and state agencies, universities, and national organizations, such as the Water Environment Federation (WEF) and National Association of Clean Water Agencies (NACWA), to better understand how the various sources may contribute to the amount of PFAS entering the wastewater treatment process and to help fill gaps in current PFAS knowledge to address the issue. Water reclamation plants (WRPs) are not original sources of PFAS and were not designed to remove these chemicals during the treatment process. 


Industrial discharges to MWRD’s water reclamation plants are regulated through an EPA-approved pretreatment program established in the MWRD’s Sewage and Waste Control Ordinance (SWCO). As the pretreatment control authority for industrial users in the MWRD’s service areas, industrial user limits are set in compliance with federal standards or local limits adopted to protect treatment processes at water reclamation plants and to comply with water quality, final effluent, and biosolids regulatory standards.

The MWRD has taken the following actions to better understand PFAS in our service area:

  • Sampled and analyzed PFAS in selected residential segments of MWRD’s collection system, representing non-industrial inputs to our WRPs.
  • Distributed the "Industrial Waste Division PFAS Initiative Screening Evaluation Survey" to 331 Significant Industrial Users (SIU) in the MWRD's service area. A total of 104 SIUs responded with completed surveys, for a response rate of 31%. Almost all respondents reported that they do not use, produce, or discharge PFAS. 
  • Provided in-kind support and sampling for a Water Research Foundation national study investigating management strategies to prevent PFAS from entering water supplies and wastewater. The project aims to gather utility data and fill data gaps to help characterize the PFAS signature associated with different known industrial point sources in the collection system. 

 ​​Next steps include:

  • PFAS sampling in MWRD intercepting sewers that service industrial areas.
  • Initial outreach and inspections of industries most likely to use and discharge PFAS.
  • Industry partnerships to investigate alternate processes and chemicals as substitutes for PFAS.
  • Direct regulation of industry under provisions of SWCO and Clean Water Act (40 CFR 403). EPA officials indicated that they would develop effluent limit guidelines for PFAS for nine industrial source categories.


Because PFAS is found in trace concentrations in wastewater, PFAS can also be found in municipal biosolids. The EPA is in the process of developing methods for analysis of biosolids. In advance of approved methods, the MWRD began testing biosolids to gain preliminary information on PFAS concentrations in biosolids. This preliminary analysis of biosolids and composted biosolids showed levels of PFAS that were within the range of concentrations found in typical biosolids across the country that were not impacted by large discharges from industries.

A comparison of PFAS concentrations in household products
PFAS concentrations in many consumer products are much higher than in biosolids.


Next steps include:

  1. Continue contributing to additional research to fill knowledge gaps. The scientific understanding of PFAS in wastewater and biosolids continues to evolve, therefore, filling knowledge gaps is critical so that decisions on PFAS in wastewater and biosolids will be based on the best science available. Much of the research done by the EPA for assessing potential impacts and developing guidance for management of biosolids are done through the funding of research conducted by universities and other research institutions. As the EPA continues to conduct research to fill data gaps as part of its PFAS Strategic Roadmap (EPA Strategic Roadmap), the MWRD will continue to take a proactive approach to collaborate on these projects by providing support in various forms, such as by providing samples and technical guidance.
  2. As the EPA finalizes its method for the analysis of PFAS in biosolids, the MWRD will continue to analyze its biosolids to gather more information on trends and variations in the levels of PFAS in its biosolids.
  3. Continue engage with technical working groups and industry associations to understand the latest science, best practices, and regulatory outlook. These groups include the Illinois Association of Wastewater Agencies, Water Environment Federation, and the U.S. Department of Agriculture W4170 Workgroup.