Ultrafiltration in Water Treatment and Its Evaluation as Pre-treatment for Reverse Osmosis System

The use of ultrafiltration technology for municipal drinking water applications is a relatively recent concept, although in the beginning, it is already commonly used in many industrial applications such as food or pharmaceutical industries. Ultrafiltration is proven to be a competitive treatment compare with conventional ones. In some cases, the combination of ultrafiltration with conventional process is also feasible particularly for high fouling tendency feed water or for removal of specific contaminants. Recently, ultrafiltration has been recognized as competitive pre-treatment for reverse osmosis system. A system designed with an ultrafiltration as pre-treatment prior to reverse osmosis system has been referred to as an Integrated Membrane System (IMS). The application of IMS is a must for sites require very extensive conventional pretreatment or where wide fluctuation of raw water quality is expected. However, the UF design was generally dismissed as commercial alternative to conventional filtration due to its high membrane cost. Nevertheless, today the UF membrane price has gone far down, even below conventional treatment system with the new coming Asian membrane industries. Therefore, there is no doubt, UF is now becoming a competitive pretreatment system for RO in a wide range of raw water quality.