Fate of Per- and Polyfluoroalkyl Substances (PFASs) in Conventional Wastewater Treatment Processes and Strategic Placement of Electrooxidation Units for Enhanced Removal

Per- and polyfluoroalkyl substances pose a high risk to human health globally, and the continuous discharge of PFAS-containing industrial wastewater would worsen the situation. This study examined the effectiveness of conventional wastewater treatment technologies in PFAS removal. The results indicate that primary and secondary sedimentation tanks can remove 8.46–22.65% of long-chain PFCAs (>6 carbons), while PFAA concentration appeared to increase during the anaerobic–oxic process due to biotransformation of PFAA precursors and desorption from activated sludge, ranging from 25.33% for PFBA to 207.31% for PFHxA. Electrooxidation showed effectiveness in PFAS removal in wastewater. Positioning the electrooxidation module between the primary sedimentation tank and the anaerobic–oxic process achieved the lowest energy consumption (63.10 kWh∙m−3) for lowering the perfluorooctanoic acid concentration to meet the standards for drinking water quality in China. The results of this study provide a basis for designing and optimizing PFAS-laden industrial wastewater treatment systems.