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).