Removal of Viruses in Membrane Bioreactors

Abstract

This review seeks to summarize the current literature regarding the removal of viruses from wastewater using membrane bioreactors (MBRs). Membrane bioreactors are an effective technology for the removal of viruses from wastewater and do so with greater efficiency than conventional activated sludge treatment plants. However, much is unclear about the capabilities and mechanisms of this process. Membrane pore size is commonly thought to be an important factor impacting virus removal, but this effect is primarily observed when the pore size is smaller than the virus diameter, and the effects vary by virus. A variety of factors can impact the effectiveness of MBRs in virus removal, with the presence of a biofilm foremost among them. Balancing the presence of a biofilm with regular membrane backwashing and cleaning to maintain consistent flux remains a critical consideration in MBR operation. Differences in reported removal efficiencies of human viruses compared to model viruses (such as bacteriophages) call into question the reliability of these model viruses in assessing the effectiveness of virus removal in MBRs. More investigation, particularly with full-scale MBR systems, must be performed to further understand the potential of MBRs in virus removal.