A Surveillance Study: Per-and polyfluoroalkyl Substances (PFAS) in Biosolids

This surveillance study was aimed at understanding concentrations of PFAS in biosolids. To address this objective, samples were collected from of twenty-five wastewater resource recovery facilities (WRRFs) throughout North America over a six-month period. A minimum of two samples were collected from each WRRF: Location A – sludge entering the stabilization process, and Location B – biosolids (post-stabilization sludge). Modified EPA Method 537.1 was used to analyze 40 PFAS compounds in these samples by Eurofins Laboratories. Only 20% of the measured PFAS compounds were detected in the biosolids samples. Three major solid stabilization methods were evaluated, anaerobic digestion, incineration, and chemical stabilization. Anaerobic digestion and chemical stabilization indicated increases in PFAS in Location B in comparison to Location A, except for in the case of incineration, where ash samples (Location B) did not contain any of the measured PFAS compounds above the method detection limit.