Ultrafiltration and Reverse Os (NF) are all pressure-driven membrane separation process. UF filter media is UF membrane, configured as flat type, tubular type and hollow fiber type. UF process is the separation process in relation with pore size, and the pore size is between RO (NF) and MF (0.001-0.1μm),that is to say UF process the separation from big molecules to small molecules. In short, ions and small molecules, dissolved in the raw water, permeate to be the UF permeate, while particles larger than the membrane pore size are concentrated as concentrate, such as big protein molecules, microorganism, colloid, suspending substance etc.