Pre-coating (EPCE®) UF membranes for direct treatment of surface water

The feasibility of ultra and microfiltration depends strongly on the achieved net flux. Direct treatment of surface water frequently results in low net fluxes and high cleaning frequencies. This is largely determined by the quality of the feed water and the mechanisms that determine the fouling and the fouling rate of the membranes. Controlling and preferably reducing the rate of fouling is a major challenge. Research has been carried out to reduce fouling to achieve a stable operation at an economical feasible net flux. This research investigates decreasing the membrane contact area for suspended and colloidal matter by a dynamic filter, i.e. Enhanced Pre-Coat Engineering (EPCE). The general applicability and the effects on the membrane performance of this new approach, has been determined on different water sources and with different pre-coat materials. Pre-coating results initially in a higher fouling rate, however this fouling rate stabilises after several filtration cycles. The stabilisation is caused by a better restoration of the permeability after a backwash and an enhanced backwash. From this research it can be concluded that EPCE is a promising technique to increase membrane performance. Long term effects, costs and full-scale implementation need to be demonstrated.