The Minnesota Biosolids PFAS Strategy was released by MPCA Jan. 17, 2025. This strategy applies to all wastewater treatment facilities that intend to apply biosolids to land. Starting in September 2025, all biosolids intended for land application must be tested for PFAS before use with response actions taken based on results.
The 2023-2024 Minnesota Legislature directed the MPCA to develop and implement a strategy to test for per- and polyfluoroalkyl substances (PFAS) in biosolids that are applied to the land. The goal of Minnesota’s biosolids PFAS strategy is to ensure protection of human health while retaining the benefits of biosolids applied to land.
Minnesota’s PFAS Biosolids Strategy
Per and poly-fluoroalkyl substances (PFAS), a group of more than 5,000 human-made chemicals, have been used widely throughout the United States in industrial processes and in consumer products. The Minnesota Biosolids PFAS Strategy will provide a better understanding where and what types of PFAS are being discharged to municipal wastewater treatment facilities (WWTFs) and support source identification and reduction efforts that are already under way at many WWTFs. It will help guide biosolids land application decisions and allow farmers and landowners to make informed decisions related to land application of biosolids.
Strategy components
- PFAS sampling: For any biosolids from a WWTF that are intended to be land applied, analysis of PFAS compounds will be required prior to land application.
- Required actions: The amount of PFAS in the sample may require the WWTF to apply at a reduced application rate or may prohibit land application.
- Reduction efforts: The amount of PFAS in the sample may require the WWTF to begin or expedite existing PFAS source identification and reduction efforts.
- Communication: The WWTF must communicate information to landowners, farmers, and the Minnesota Pollution Control Agency (MPCA) about the level of PFAS in biosolids and source identification and reduction efforts underway.
Background
Biosolids, the organic matter generated in the wastewater treatment process, are useful. They can be applied to land bringing much needed organic matter and macro- and micronutrients to soil. Land application of biosolids also promotes carbon sequestration, provides an economical way for wastewater treatment plants to manage biosolids, and keeps the biosolids out of landfills. In Minnesota, about 20 percent of the biosolids generated are applied to land, mostly on farm fields but also for reclamation of lands. Biosolids are applied to less than 0.1 percent of land that grows crops in Minnesota.
Because biosolids are a byproduct of treating wastewater that may contain PFAS, biosolids may contain PFAS. PFAS can enter municipal wastewater treatment facilities from many sources: industry, business, and homes. PFAS at high levels in biosolids could contaminate soils, surface water, and groundwater and even be absorbed by crops.
We expect most biosolids will have low PFAS levels, but the need to understand and reduce PFAS in biosolids is important because exposure to PFAS can be harmful.
The Minnesota Biosolids PFAS Strategy will provide a better understanding of where and what types of PFAS are being discharged to municipal wastewater treatment facilities and support source identification and reduction efforts that are already under way at many WWTFs. It will help guide biosolids land application decisions and allow farmers and landowners to make informed decisions related to land application of biosolids.
Developing this biosolids strategy
In November 2024, the MPCA released a proposed Minnesota Biosolids PFAS Strategy, solicited public feedback, and held a public information session. During the public review period, the agency received feedback that informed the final strategy, including minor adjustments to the tier levels, clarifying sampling and notification requirements, and adding additional communication to the landowner and farmers. Moving forward MPCA will continue to work with stakeholders to better understand actions needed to protect human health, including any impacts to drinking water.
Just days before finalizing this Minnesota strategy, U.S. EPA published a draft biosolids health risk assessment for PFAS. The Minnesota strategy mirrors EPA’s recommendations for states to monitor biosolids for PFAS, identify likely industrial discharges of PFAS, and implement industrial pretreatment where appropriate. But due to the timing, the Minnesota Biosolids PFAS Strategy does not reflect the content of EPA’s draft risk assessment. The MPCA will continue to evaluate this strategy and make adjustments, as appropriate.
Informational webinar
The MPCA held an information session about our draft strategy for PFAS in biosolids from wastewater treatment facilities that are applied to land. (Nov. 19, 2024)