Per- and Poly- Fluoroalkyl Substances (PFAS) are a large family of organic compounds, including more than 5,000 artificial fluorinated organic chemicals used since the 1940s. They have been used extensively in surface coatings and protectant formulations for consumer products including paper and cardboard packaging products, carpets, leather products and clothing, construction materials, and non-stick coatings.
Recent studies have shown PFAS in WWTP influents to be in the tens to hundreds of nanograms per liter (ng/L). Conventional sewage treatment methods do not efficiently remove PFAS. Application of biosolids from WWTPs as a soil amendment can result in a transfer of PFAS to soil, which can then leach to groundwater or be available for uptake by plants and soil organisms and biomagnify to grazing livestock. PFAS have been detected in soils, groundwater, crops, and livestock near agricultural fields that receive PFAS-contaminated biosolids, fueling public concern.
As PFAS are recalcitrant and are not removed through conventional wastewater treatment, management of PFAS in biosolids is gaining increased concern and scrutiny.
This presentation will address the following questions related to PFAS in wastewater and biosolids:
- What are PFAS?
- Why are PFAS in wastewater?
- What is the fate of PFAS in biological treatment systems?
- What is the current status of regulations related to PFAS in biosolids
- What technologies can be used to treat PFAS in biosolids?
Data will be presented on PFAS measured in biosolids before and after various biosolids treatment technologies including digestion, composting, drying, and pyrolysis. This presentation will help utility planners, operators, engineers and administrators understand the nature of the PFAS issue, how these compounds are introduced into wastewater and biosolids, the rapidly changing regulatory landscape, and what technologies are being used to eliminate these compounds from biosolids products.