Biosolids as a key pathway for the release of poly- and perfluoroalkyl substances (PFAS) from wastewater treatment plants into the environment

Purpose: Poly- and perfluoroalkyl substances (PFAS) are widely used in industrial and consumer products, leading to their continuous entry into wastewater streams. Consequently, wastewater treatment plants (WWTPs) have become major pathways for PFAS release into the environment. Although many studies have examined PFAS behavior in WWTPs, limited attention has been paid to their distribution, transformation, and persistence in sludge. Methods: A systematic review of peer-reviewed studies was conducted to synthesize current knowledge on PFAS occurrence, fate, and transport within sludge. The review focused on identifying biological and physicochemical factors influencing PFAS transformation and adsorption processes in WWTPs. Results: Findings indicate considerable variability in PFAS concentrations across treatment plants, largely influenced by aqueous-to-solid partitioning behavior. Sludge from wastewater containing higher PFOS and PFOA levels typically exhibits elevated PFAS accumulation. Biological pathways, including cytochrome P۴۵۰ monooxygenase activity, transamination, and beta-oxidation, appear to play roles in PFAS biotransformation, though precursor-specific effects remain unclear. Conclusion: Overall, the review highlights the complex interplay between chemical structure, biological activity, and wastewater composition in determining PFAS behavior in biosolids. Understanding these interactions is essential for developing effective management strategies to mitigate PFAS persistence and environmental release from WWTPs.

کلیدواژه ها:

Per- and polyfluoroalkyl substance ، PFAS ، Wastewater treatment plant ، Biosolids