Performance and microbial community structure in an integrated anaerobic fluidized-bed membrane bioreactor treating synthetic benzothiazole contaminated wastewater

•Integrated anaerobic membrane bioreactor was used to treat benzothiazole wastewater.•The accumulation of VFAs increased with the addition of benzothiazole.•The biodegradation of benzothiazole was increased by the adaptation of microbes.•Acetotrophic methanogens were more sensitive to the addition of benzothiazole.

This study investigated the impact of benzothiazole on the performance and microbial community structures in an integrated anaerobic fluidized-bed membrane bioreactor fed with synthetic benzothiazole wastewater (with gradually increasing doses of benzothiazole (1-50 mg/L)). The addition of benzothiazole had an adverse effect on volatile fatty acids accumulation (from 10.86 mg/L to 57.83 mg/L), and membrane fouling (service period from 5.9 d to 5.3 d). The removal efficiency of benzothiazole was 96.0%. Biodegradation was the major benzothiazole removal route and the biodegradation efficiency obviously improved from 25.7% to 98.3% after adaptation. Sludge 1 (collected on day 58 without benzothiazole) and sludge 2 (collected on day 185 with 50 mg/L benzothiazole) were analyzed using the Illumina®MiSeq platform. The most abundant genera were Trichococcus (43.1% in sludge 1) and Clostridium sensu stricto (23.9% in sludge 2). The dominant genus of archaea was Methanosaeta (90.3% in sludge 1 and 80.8% in sludge 2).