Peak flux performance and microbial removal by selected membrane bioreactor systems

Removal of Pathogens by Membrane Bioreactors: A Review of the Mechanisms, Influencing Factors and Reduction in Chemical Disinfectant Dosing

“…For example, Wu et al [73] found LRV to be in good correlation with the ratio of phage size/pore size. On the other hand, indigenous MS2 was undetectable in the effluent of all tested MBR systems with a range of membrane pore sizes (0.03-0.1 μm), suggesting that removal mechanisms other than straining may exist in MBRs [51]. However, when MS2 coliphage (0.03 μm) was spiked to an MBR treating municipal wastewater, pore size effect became more apparent [51].…”

“…On the other hand, indigenous MS2 was undetectable in the effluent of all tested MBR systems with a range of membrane pore sizes (0.03-0.1 μm), suggesting that removal mechanisms other than straining may exist in MBRs [51]. However, when MS2 coliphage (0.03 μm) was spiked to an MBR treating municipal wastewater, pore size effect became more apparent [51]. The MF membrane with 0.1 μm pore size showed a log removal of 1.7, but the membranes with 0.03 μm pore size showed a log removal of 4.4.…”

“…This has implications for scaling up as lower flux implies requirement of higher membrane surface area [42]. On the other hand, based on their 18-month study, Hirani et al [51] found no correlation between peak flux and LRVs. Over a tested range of 7.5-12.5 L/m 2 ·h, Wu et al [73] observed little effect of flux of a 0.4 µm clean membrane on LRV.…”

“…Similarly, while looking at the removal of human enteric viruses from a full scale MBR plant, Simmons et al [45] found that compared to human adenovirus (5.5 log removal), human enterovirus (5.1 log removal) and norovirus (3.9 log removal) were removed with lower efficiencies. In a study by Hirani et al [51] the log removal of total and faecal coliform varied from 5.8 to 6.9 and 5.5 to 6.0, respectively, showing some impact of the indicator organism chosen on the perceived bacteria removal efficiency. Notably, the lower LRVs of faecal coliform, despite the generally expected similar removal of total and faecal coliforms due to the similarity of their particle sizes, was attributed to lower influent concentrations of the former.…”

Risk assessment of Giardia from a full scale MBR sewage treatment plant caused by membrane integrity failure

“…Theoretically, an intact MBR (average membrane pore size 0.01-0.4 μm) is a barrier to pathogens and suspended solids larger in size than the membrane pore size, and therefore can offer better pathogen removal than conventional treatment. As a result, total coliform reduction can reach an average of log7 (Hirani et al, 2010). However, our study showed that high concentrations of Giardia (>4 μm) could occur in the MBR effluent caused by membrane integrity failure.…”