Effects of perfluorooctanoic acid and perfluorooctane sulfonic acid on microbial community structure during anaerobic digestion

Per- and polyfluoroalkyl substances (PFASs) are recalcitrant organic pollutants, which accumulate widely in aquatic and solid matrices. Anaerobic digestion (AD) is one of possible options to manage organic wastes containing PFASs, however, the impacts of different types of PFAS on AD remains unclear. This study aimed to critically investigate the effects of two representative PFAS compounds, i.e., perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), on the AD performance and microbial community structure. 100 mg/L of both PFOA and PFOS considerably inhibited the AD performance and changed the microbial community structure. Especially, PFOA was more toxic to bacterial and archaeal activity than PFOS, which was reflected in AD performance. In addition, the sulfonic acid group in PFOS affected the changes in microbial community structure by inducing abundant sulfate reducing bacteria (i.e., Desulfobacterota). This study provides a significant reference to the response of AD system on different PFAS types and dosage.