Ultrafiltration is a separation technique that uses membranes of pore size 0.1 to 0.001 microns. The process is similar to Reverse Osmosis, using hydrostatic pressure to force water through a semi-permeable membrane. The method is used for removing impurities of high molecular weight.

It can remove organic and inorganic polymeric molecules and colloidal material. However, it is ineffective in removing low molecular weight ions or molecules. Ultrafiltration (UF) is a pressure-driven barrier to suspend solids, bacteria, viruses, endotoxins and other pathogens to produce water with very high purity and low silt density.

Ultrafiltration is a variety of membrane filtration in which hydrostatic pressure forces a liquid against a semi permeable membrane. Suspended solids and solutes of high molecular weight are retained while the water and low molecular weight solute passes through the membrane.

Ultrafiltration is not fundamentally different from reverse osmosis or nanofiltration, except in terms of size of the molecules it retains.

A membrane or more properly, a semi permeable membrane, is a thin layer of material capable of separating substances when a driving force is applied across the membrane. The use of Ultrafiltration are increasingly employed for the removal of bacteria and other microorganisms, particular material, and natural organic material, which can impart colour, tastes and odours to the water and react with disinfectants to form disinfection by products (DBP).

Using Ultrafiltration there are no need for chemicals ( coagulants, flocculates, disinfectants and pH adjustment ). There is size exclusion filtration rather as opposed to media depth filtration. Good constant quality of the treated water in terms of the particulate and microbial removal. Relative small size and plant compactness. Simple automation, being also environmentally friendly with it low chemical use and discharge.