Ultrafiltration is a low- pressure driven membrane separation process that separates particulate matter from soluble components in the carrier fluid (such as water) at transmembrane pressures of, typically, 0.5 to 5 bars. UF membranes typically have pore sizes in the range of 0.01 - 0.10 µm and have a high removal capability for bacteria and most viruses, colloids and silt. The smaller the nominal pore size, the higher the removal capability.
UF membranes can be fabricated essentially in one of two forms: tubular or flat sheet. Membranes of these designs are normally produced on a porous substrate material. The single operational unit into which membranes are engineered for use is referred to as a module. This operational unit consists of the membranes, pressure support structures, feed inlet, concentrate outlet ports, and permeate draw-off points.
Operation of UF membrane can be performed in two different service modes, i.e., dead-end flow and cross-flow. The dead-end flow mode of operation is similar to that of a cartridge filter where there is only a feed flow and filtrate flow.