Pyrosequencing reveals microbial community profile in anaerobic bio-entrapped membrane reactor for pharmaceutical wastewater treatment

Kok Kwang Ng, Xueqing Shi, Say Leong Ong, How Yong Ng

Abstract

In this study, pharmaceutical wastewater with high salinity and total chemical oxygen demand (TCOD) was treated by an anaerobic membrane bioreactor (AnMBR) and an anaerobic bio-entrapped membrane reactor (AnBEMR). The microbial populations and communities were analyzed using the 454 pyrosequencing method. The hydraulic retention time (HRT), membrane flux and mean cell residence time (MCRT) were controlled at 30.6 h, 6 L/m²h and 100 d, respectively. The results showed that the AnBEMR achieved higher TCOD removal efficiency and greater biogas production compared to the AnMBR. Through DNA pyrosequencing analysis, both the anaerobic MBRs showed similar dominant groups of bacteria and archaea. However, phylum Elusimicrobia of bacteria was only detected in the AnBEMR; the higher abundance of dominant archaeal genus Methanimicrococcus found in the AnBEMR could play an important role in degradation of the major organic pollutant (i.e., trimethylamine) present in the pharmaceutical wastewater.

Keywords: Pharmaceutical wastewater; High salinity; Anaerobic membrane bioreactor; Entrapped biomass; Microbial analysis.