Membrane Ageing and Replacement – Impact on Pathogen Removal in Full-Scale MBR

The aim of this study was to assess temporal changes in log removal values (LRV) for a suite of microorganisms, for time scales relevant to the expected life of modern MBR modules. A higher level of fouling on the older membranes likely improved rejection, although not consistently, when compared to new clean membranes. Larger bacteria and protozoan indicator removal efficiencies increased following replacement, indicating improved size exclusion by the new membranes. The results of this study suggest that within 10 years, no significant decline in LRV is expected. Unless gross, easily detectable, membrane integrity failure occurs, a MBR will continue to produce high quality water.