Effective removal of methyl siloxane from water by sewage activated sludge microbes: biodegradation behavior and characteristics of microbial community

Current approaches of polydimethylsiloxanes (PDMS) treatment mostly rely on transferring from the liquid phase to other phases (gas and solid), leaving secondary pollution risks. In this study, biodegradation of PDMS in wastewater was found with activated sludge collected from real wastewater treatment plants (WWTPs). The highest biodegradation rates of dodecamethylpentasiloxane (L5) and tetradecamethylhexasiloxane (L6) reached up to 58.3% and 21.4% within 5-day anaerobic incubation at 37 °C under shaking at 100 rpm. Moreover, the microbial communities were investigated by using Illumina high-throughput sequencing of 16S-rRNA, which pointed Clostridium spp. as a potential candidate responsible for the biodegradation of PDMS under anaerobic condition. Notably, this is the first report of effective biodegradation of PDMS by microbes in activated sludge. This study could open up possibilities for bioavailable methods to depollute other emerging organic pollutants in water.