A Critical Review of PFAS Analysis, Occurrence, and Fate in Wastewater Treatment Plants

Wastewater treatment plants (WWTPs) receive per- and polyfluoroalkyl substances (PFAS)-containing waste streams including municipal sewage, industrial waste, landfill leachate, and firefighting wastewater. The widespread use of PFAS in commercial and industrial applications results in complex mixtures entering WWTPs. Given the centrality of WWTPs to the cycling of these harmful contaminants, comprehensive identification and quantification of PFAS in WWTPs is an essential research topic. Herein we review research on the distribution and fate of PFAS in WWTPs globally and synthesize data from 505 WWTPs in 39 screened studies conducted since 2020. We examine common sampling methods, analytical techniques, and PFAS targeting strategies. PFAS concentrations vary widely across matrices, with target PFAS ranging from 0.8 ng/L to 66.9 μg/L in influents, 0.5 ng/L to 107 μg/L in effluents, and 0.001 to 533.6 ng/g dry weight in sludge. While legacy compounds like PFOA and PFOS remain prevalent, short-chain PFAS now dominate. Across 259 WWTPs, no significant difference was found between influent and effluent target PFAS concentrations, and removal efficiencies were generally low or negative. Up to 86% of total organic fluorine in influents was attributed to untargeted precursors, underscoring the need for further research into PFAS transformation and fate during treatment.