Effect of membrane configuration on bench-scale MF and UF fouling experiments

Hollow fiber and flat sheet membranes were compared in side-by-side bench-scale experiments to evaluate whether the configuration has an impact on the rate of membrane fouling. Both microfiltration (MF) and ultrafiltration (UF) membranes were evaluated. In general, flat sheet membranes fouled more rapidly than hollow fiber membranes. Pretreatment such as coagulation generally affected both configurations similarly, but in some cases coagulation reduced fouling on hollow fiber membranes but increased fouling on flat sheet membranes. Prefiltration to remove foulants above 1microm in size had a consistent effect on both configurations. A bench-scale apparatus employing a single-fiber module that allows testing over multiple filter runs with integral backwashing capabilities was demonstrated to provide more detailed information about fouling, which can be applied to full-scale applications. When bench-scale tests are to be used to screen treatment options for full-scale applications, the use of a backwashable hollow fiber system is recommended.