Evaluation of system performance and microbial communities of a bioaugmented anaerobic membrane bioreactor treating pharmaceutical wastewater

In this study, a control anaerobic membrane bioreactor (C-AnMBR) and a bioaugmented anaerobic membrane bioreactor (B-AnMBR) were operated for 210 d to treat pharmaceutical wastewater. Both the bioreactors were fed with the pharmaceutical wastewater containing TCOD of 16,249 +/- 714 mg/L and total dissolved solids (TDS) of 29,450 +/- 2209 mg/L with an organic loading rate (OLR) of 13.0 +/- 0.6 kgCOD/m(3)d. Under steady-state condition, an average total chemical oxygen demand (TCOD) removal efficiency of 46.1 +/- 2.9% and 60.3 +/- 2.8% was achieved by the C-AnMBR and the B-AnMBR, respectively. The conventional anaerobes in the C-AnMBR cannot tolerate the hypersaline conditions well, resulting in lower TCOD removal efficiency, biogas production and methane yield than the B-AnMBR seeded from the coastal shore. Pyrosequencing analysis indicated that marine bacterial species (Oliephilus sp.) and halophilic bacterial species (Therrnohalobacter sp.) were only present in the B-AnMBR; these species could possibly degrade complex and recalcitrant organic matter and withstand hypersaline environments. Two different dominant archaeal communities, genus Methanosaeta (43.4%) and Methanolobus (61.7%), were identified as the dominant methanogens in the C-AnMBR and the B-AnMBR, respectively. The species of genus Methanolobus was reported resistant to penicillin and required sodium and magnesium for growth, which could enable it to thrive in the hypersaline environment. (C) 2015 Elsevier Ltd. All rights reserved.