Michigan farmers who use biosolids from wastewater treatment plants (WWTPs) as a fertilizer will soon receive new data with their deliveries, detailing testing results for Perflurooctane Sulfonate (PFOS) that may enter WWTPs from certain industrial and commercial sources.
“Biosolids are an important nutrient source for farmers: They contain nutrients, they have been treated to remove contaminants, they are low cost, and they provide a win-win for communities and agriculture,” said Laura Campbell, Michigan Farm Bureau Agriculture Ecology Department manager. “When nutrients are recycled from a WWTP and used to grow crops instead of going to a landfill or being incinerated, that provides both an environmental benefit and a cost savings benefit.”
Perfluorooctane Sulfonate is one of numerous fluoroalkyl substances sometimes referred to as “forever chemicals.” Under normal conditions, this large group of chemicals does not break down for years or decades. Some types of PFAS are known to travel through water and air and can linger in the environment, including agricultural areas.
Biosolids and their use are regulated by the Michigan Department of Environment, Great Lakes, and Energy and the U.S. Environmental Protection Agency, which require biosolids to undergo a treatment process and be tested for certain pollutants.
That process will now include a protocol from EGLE in place for WWTPs biosolids that may be impacted by industrial PFAS discharges, including monitoring requirements and a threshold concentration maximum of 150 parts per billion for PFOS in biosolids. Biosolids deliveries from Michigan WWTPs will include the most recent PFOS testing results for that WWTP’s biosolids.
With this new program, the Michigan PFAS Action Response Team (MPART) is working with wastewater recovery facilities to reduce the chance PFAS chemicals that might enter the facility from an industrial source from making it through the treatment process and into biosolids headed for a farm field.
“Farmers will receive letters or fact sheets from the WWTP or their application contractor showing that the facility is meeting the State of Michigan’s standards for reduction of PFAS chemicals,” Campbell said. “This will help the WWTP demonstrate how their biosolids treatment and the new monitoring requirement are working, and help the farmer to know they can land apply those nutrients without worrying about what’s in them.”
Some studies have shown certain PFAS may be harmful to humans, with data suggesting links to developmental disorders, thyroid disease, immune deficiencies, and cancer. More studies are underway to determine the impacts these chemicals can have on animals, animal products, and crops.
PFAS were used for decades in industrial, commercial, and domestic settings as part of things like firefighting foam, chrome plating, fire retardant and waterproofing on clothing, carpet, textiles, stain resistance, and even food wrappers.
The use of some PFAS, including PFOS, have been phased out and are no longer approved in the United States. However, the past prevalence of PFOS use means some WWTPs may receive discharges from industrial or commercial sources who have used PFOS in the past, which means the chemicals may show up in treated wastewater and biosolids.
WWTPs with biosolids higher than the threshold must establish long-term measurement for pre-treatment, eliminate industrial sources for PFOS and show PFOS concentrations in the biosolids they produce are consistently testing below 150 ppb for PFOS before they will be allowed to land apply biosolids.
More information on biosolids from the Michigan Water Environment Association web page at https://www.mi-wea.org/biosolids_-_land_application.php, and more about PFAS by visiting the Michigan PFAS Action Response Team PFAS Land Application Workgroup web page at www.Michigan.gov/PFASLandApplication.
The staff listed on the Statewide Biosolids and PFAS Contact map found at www.michigan.gov/documents/egle/egle-mdard-biosolids-pfas-staff_720327_7.pdf can also be contacted for more information.