Understanding the Impact of New Pollutant Perfluorooctanoic Acid On the Enhanced Biological Phosphorus Removal Processes

Perfluorooctanoic acid (PFOA), an emerging contaminant, is frequently detected in wastewater treatment plants. However, the impact of PFOA on enhanced biological phosphorus removal (EBPR) processes in wastewater treatment and the associated mechanisms remain poorly characterized. To address this knowledge gap, a laboratory-scale sequencing batch reactor (SBR) was operated under mesophilic conditions to systematically evaluate the effects of PFOA on EBPR performance, sludge properties, and microbial metabolic functions. The results demonstrated that low PFOA concentrations (<= 0.5 mg/L) enhanced the removal of chemical oxygen demand (COD) and nutrients. However, at concentrations exceeding 0.5 mg/L, COD and phosphate removal efficiencies declined markedly, whereas ammonia nitrogen removal was not significantly inhibited. High concentrations of PFOA decreased the metabolic transformation of COD and phosphate during the typical cycle, reduced the synthesis of intracellular polymer polyhydroxyalkanoates (PHA), but stimulated glycogen metabolism. High concentrations of PFOA decreased the specific oxygen uptake rate but increased the release of reactive oxygen species (ROS) and lactate dehydrogenase (LDH), collectively impairing microbial metabolic activity. These findings advance the understanding of PFOA's environmental fate in wastewater systems and offer novel mechanistic insights into its interference with EBPR performance.