The effect of coagulation with MF/UF membrane filtration for the removal of virus in drinking water

Removal of phage MS2 in drinking water by pre-coagulation and filtration through ultrafiltration (UF) and microfiltration (MF) membranes was investigated in a laboratory test unit. Two commercial aluminium-based coagulants (ALG and PAX) were used. The low (≤1–30 pfu/mL) numbers of infective virus detected in permeates show that pre-coagulation/flocculation in combination with both loose UF and MF membrane filtration was an effective hygienic barrier against MS2 virus. Without pre-coagulation/flocculation, no (MF) or only a minor (UF) virus removal was observed. The two coagulants provided high virus removal efficiencies (>7.4 logs) after UF and MF membrane filtration using doses of 5 mg Al/L. Reducing the dose of coagulants to 3 mg Al/L had only a small effect on the removal efficiency, which remained high after UF membrane filtration, and ALG/MF membrane filtration (>7.1 logs). The virus removal obtained with PAX (3 mg Al/L) and MF membrane filtration was slightly less (6.7 logs) than for the other conditions. Combined removal of virus and colour by pre-coagulation/flocculation and MF membrane filtration was also investigated. The low concentrations of both virus and colour in the permeate indicate that low-pressure MF filtration in combination with pre-coagulation/flocculation is a potential efficient technology for removal of virus and colour in drinking water.