Occurrence and Mass Estimate of Perfluoroalkyl Substances (PFAS) in Malaysian Sewage Treatment Plants: A Case Study of Penang

ABSTRACT This study investigates the occurrence and mass loading of perfluoroalkyl substances (PFAS) in sewage treatment plants (STPs) across Penang, Malaysia. Seventeen PFAS compounds were analysed in influent and effluent samples from 10 STPs serving approximately 700 000 residents. The highest influent concentrations were recorded for perfluoropentanoic acid (PFPeA) at 5329.7 ng/L and perfluorooctanoic acid (PFOA) at 2634.6 ng/L. After treatment, concentrations of PFPeA and PFOA were reduced to 430.0 and 672.5 ng/L, respectively. Eight of the 10 STPs achieved PFAS removal efficiencies exceeding 50%. Although recent technologies such as nanofiltration membranes, modified activated carbon and hybrid advanced oxidation processes have demonstrated effectiveness in PFAS removal, these methods are not yet adopted in Malaysia. Using a wastewater‐based epidemiology (WBE) approach, the highest mass load was observed at STP Bandar Baru Bertam Perdana (4799.5 mg/1000 inhabitants/day). These findings provide essential baseline data to inform regulatory strategies for PFAS control in Malaysia.