Unveiling the fate and transformation of per- and polyfluoroalkyl substances (PFAS) in full-scale semiconductor wastewater treatment.

The fate and removal of per- and polyfluoroalkyl substances (PFAS) within semiconductor wastewater treatment trains remain inadequately characterized. This study profiles seven segregated wastewater treatment systems and four core processes within a semiconductor facility to elucidate the occurrence, phase-partitioning, and removal of 24 PFAS. Wastewater was dominated by short-chain PFAS and emerging alternatives, with ∼47% of the PFAS load partitioned into the particulate-bound phase across the effluents of the seven segregated systems. Removal efficiencies varied widely (-472-69%), identifying the F and LSR systems as control nodes. Process evaluation revealed that chemical precipitation in the F system induced sludge partitioning of long-chain PFAS and secondary desorption of short-chain fractions, while adsorption units in the LSR system experienced rapid breakthrough, relying on terminal ion-exchange resins. Mass balances revealed that combined output (1.58 kg/year retention and 0.67 kg/year effluent) exceeded the influent (1.49 kg/year), indicating the inferred biotransformation of unquantified precursors. PFOS maintains an elevated risk quotient ( > 1) in the effluent, while the flux of short-chain alternatives demands monitoring attention. These findings demonstrate limitations of semiconductor wastewater treatment in PFAS interception and underscore the need to monitor nodes and reevaluate the safety of short-chain homologues and emerging PFAS alternatives.