Ultra filtration (UF) is a pressure-driven barrier to suspended solids, bacteria, viruses, endotoxins and other pathogens to produce water with very high purity and low silt density. Typically, ultra filtration will remove high molecular-weight substances, colloidal materials, silt (SDI), and organic and inorganic polymeric molecules.
It serves as a pretreatment for surface water, seawater and biologically treated municipal effluent before reverse osmosis and other membrane system. UF works on low pressures ( range from 1 to 10 bar). Hallow fibre or spiral wound membranes are used for the construction of UF plant.