Effect of pH on UF membrane fouling

The effect of pH on membrane fouling with and without coagulation pretreatment was investigated. In order to better understand fouling at different pH values, the filtration resistance was divided into membrane resistance, reversible resistance and irreversible resistance. The reduction in pH could decrease molecular size of NOM and enhance the adsorption onto membrane, resulting in a significant fouling. With coagulation as pretreatment, the reduction in pH could enhance NOM removal by coagulation and reduce the concentration of NOM in feed water for membrane filtration, resulting in mitigation of fouling. Nevertheless, after coagulation, fouling could occur at a lower pH.