New insights into mechanism of emerging pollutant polybrominated diphenyl ether inhibiting sludge dark fermentation.

Polybrominated diphenyl ethers (PBDEs), derived from electronics, furniture, etc., are detected with high level in excess sludge (ES). In this work, the influence of PBDEs on ES dark fermentation (ESDF) hydrogen production and the related key mechanisms were explored. The result shows PBDEs exposure reduced hydrogen production, and hydrogen accumulation decreased from 17.6 mL/g in blank to 12.3 mL/g with 12.0 mg/Kg PBDEs. PBDEs induced the reactive oxygen species production, which directly led to cell inactivation and reduced hydrogen production. Furthermore, PBDEs decreased ES disintegration, hydrolysis, acidification and homoacetogenic processes and inhibited the activities of enzymes related to hydrogen production. PBDEs also affected the diversity and richness of microbial communities in dark fermentation systems, especially high doses of PBDEs reduced the relative abundance of microorganisms associated with hydrogen production. In conclusion, PBDEs reduce hydrogen generation from ES.