for Micro particle range (bacteria)
Microfiltration is a membrane separation technique in which very fine particles or other suspended matters, with a particle size in the range of 0.1 to 1.5 microns, are separated from a liquid. It is capable of removing suspended solids, bacteria or other impurities. Microfiltration membranes have a nominal pore size of 0.2 microns. At this level of filtration there are many substitute filtration techniques and media (sand, clay, cartridge filters, bag filters etc). This is due to the overlap in size range with regular particulate pre- filtration. It is advised to use membrane filtration to remove micro-organism and/or bacteria from the water as membrane are a physical barrier and passage through is impossible. Off course the required pore size needs to be specified correctly. In addition, most substitute filtration methods are prone to uncertainty of effluent water quality due to channelling, clogging and saturation of the filter medium.