Assimilation of 17α-ethinylestradiol by sludge and its stress on microbial communities under aerobic and anaerobic conditions.

The efficiency of 2 common types sludge, activated sludge and digesting sludge, to biodegrade ethinylestradiol (EE2) under aerobic and anaerobic conditions, and the impacts of EE2 on microbial community structure were investigated. The results showed that 75%–88% EE2 were removed under aerobic conditions and the values were 75%–84% under anaerobic conditions. The diversity of microbial species in the tested sludge decreased when exposed to EE2 and the shift of microbial community structures was dependent on both sludge types and process conditions. Predominant bacteria were identified as Proteobacteria class which was considered to have EE2 degradation capacities. Twelve strains were found, 8 of them belonged to the Class of γ-proteobacterium, 1 of β-proteobacterium, 1 of Actinobacterium, and 2 of unclassified strains.