Influence of detention times on two-stage anaerobic membrane bioreactor performance (AnMBR)

Abstract

Domestic wastewater treatment using anaerobic membrane bioreactors has the potential to produce similar effluent quality as aerobic membrane bioreactors. Employing anaerobic treatment has additional advantages such as low solids production and the ability to generate biogas.

The objective of this study is to investigate the influence of detention times on a two stage anaerobic membrane bioreactor. The other objective is to determine how GAC supplementation aids in membrane fouling control. The first stage anaerobic fluidized bioreactor removes most of the organics from the low strength wastewater. Effluent from the first stage is further polished in the second stage anaerobic fluidized membrane bioreactor. The two stage anaerobic membrane bioreactor system is operated at different hydraulic retention times to determine the influence on treatment performance. At the highest hydraulic retention time, the effect of GAC and fluidization were also studied. The experimental results show that hydraulic retention time has minimal effect on COD removal efficiency. With decreasing hydraulic retention time, rate of membrane fouling increased as observed from the transmembrane pressures. The addition of GAC helps in removing organics and but could contribute to higher transmembrane pressures.