Abstract

Centralized industrial wastewater presents a major challenge due to its high pollutant loads and the presence of persistent micropollutants such as per- and polyfluoroalkyl substances (PFAS), which pose significant risks to human health and the environment. Membrane bioreactor (MBR) technology is highly regarded for its high organic removal efficiency, environmental friendliness, and cost-effectiveness. Although PFAS removal by MBR remains limited, it has been reported that a fraction of PFAS can be transferred from the aqueous phase to the biomass through adsorption. Therefore, this study was conducted to evaluate the co-treatment performance of COD, NH₄⁺-N, and PFAS in centralized industrial wastewater. The lab-scale MBR system was operated at a flux of 6 L/m².h (LMH). The results showed that the COD and NH₄⁺-N removal rates reached 258 ± 103 mg COD/g VSS.day and 31.6 ± 7.6 mg NH₄⁺-N/g VSS.day, respectively. For PFAS, the concentrations of 9 out of 11 compounds, including PFHxA, PFHpA, PFOA, PFBS, PFHxS, PFHpS, PFOS, PFDoA, and PFTrA, increased after treatment, likely because PFAS precursors were degraded and transformed into terminal PFAS compounds. In particular, PFOS concentrations markedly increased from 97.5 ng/L to 142.0 ng/L. In contrast, PFUnA and PFDA concentrations decreased, but only to a very limited extent. These results indicate that the MBR system is effective for organic pollutant removal. However, to remove trace-level, poorly biodegradable pollutants such as PFAS, the MBR needs to be coupled with additional physico-chemical treatment processes.