Turning Up the Heat: Fate of PFAS in Biosolids Dryer and Pyrolysis System

Presentation Description: Perfluoroalkyl and polyfluoroalkyl substances (PFAS) have become an important environmental contaminant of concern, particularly for water resource recovery facilities that face increasing scrutiny regarding disposition of wastewater solids (biosolids when stabilized). In the United States, concerns regarding PFAS release to soils, groundwater, and agricultural crops from land application have increased scrutiny on traditional solids management outlets.

Thermal degradation of PFAS in wastewater solids (inclusive of sludges and biosolids) has been demonstrated, and the extent of that degradation in the various thermal processes has been identified as an area of further study. This presentation will present the findings from two full-scale studies looking at the fate of PFAS through a municipal biosolids rotary drum dryer and the only operating pyrolysis system processing municipal biosolids. Both full-scale installations include a regenerative thermal oxidizer, which is the most widely applied air pollution control device for biosolids drum drying. To the authors’ knowledge, this is the first comprehensive study to evaluate the fate of PFAS through a full-scale biosolids rotary drum dryer and pyrolysis system, including their respective emissions control technologies and gas-phase outputs. These findings are especially timely as WRRFs increasingly adopt thermal treatment technologies in response to evolving PFAS regulations, offering foundational data to guide future PFAS management strategies in wastewater solids treatment.