Per- and polyfluoroalkyl substances (PFAS) are have been under environmental concerns due to their recalcitrant behavior and human health risks derived from their bioaccumulation and toxicity. It has been reported that various wastewater including excess sludge and aqueous film forming foam can contain up to mg/L level of PFAS. In this study, we investigated the effects of two representative PFAS, i.e., perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), during anaerobic digestion and the possibility of PFAS degradation by the AD. To explore the fate and transformation of PFAS, we examined biochemical CH<sub>4</sub> potential (BMP) test with different dosage of PFOA (0.1–100ppm, namely, A0.1–A100) and PFOS (0.1–100pm, namely, S0.1–S100) containing synthetic wastewater and compared to condition without any PFAS (Control) at 37 oC for 28 days. Both PFOS and PFOA for concentration of 0.1–10 ppm did not show any inhibitory effects on AD performance with CH<sub>4</sub> production (MP; 230.8–234.2 ml) and COD removal (CODr; 92–93%) compared to Control (237.3 ml and 93%, respectively). However, the inhibition of AD performance (i.e., MP and CODr) exerted by PFAS appeared for the synthetic wastewater containing 100 ppm of both PFOA (A100) and PFOS (S100). A100 showed significant inhibition of both MP and CODr by 21.5 and 32.4%, compared with those of the control until 21-day. However, after 21-day, the MP and CODr was recovered gradually and showed MP of 151.8 ml and CODr of 79.1%, which are 64.0 and 85.3%, respectively, of those of the control at 28-day. These results suggest that PFOA had become less toxic to microbial community structure as PFOA was degraded into less toxic compounds or as microbial community structure gradually adapt to PFOA. Meanwhile, S100 also showed inhibition of AD performance at initial stage, but quickly recovered, resulting in similar results (MP, 228.8 ml; CODr, 92%) to the control at 28-day. This means that PFOS was degraded more easily into less toxic compounds or was less toxic to microbial community structure than PFOA. Overall, PFAS had significant inhibitory effects during AD above certain concentration (100 ppm in this study) and PFOA showed higher toxicity than PFOS.

Fate, transformation, and effects of per- and polyfluoroalkyl substance during anaerobic digestion

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.