(1) Grate filtration: The filter medium is gridlines or for removing coarse suspended solids, such as weeds, rags, fibers and pulp. Typical equipment grille, screen and microfiltration.
(2) Microfiltration: The shaping filter, such as cloth, filter, sintered filter tubes, honeycomb filters, etc., can also be pre-coated filter aid (eg diatomaceous earth) formation of pores in the filter medium fine the filter cake, for removing fine particles diameter. Goods stereotypes many devices.
(3) Membrane filtration: The use of special filter media as a semi-permeable membrane, a certain driving force (e.g., pressure, electric force, etc.) under the filter membrane pores due to the extremely small and the selective removal of the water can be bacteria, viruses , organics and dissolved solutes. Major equipment reverse osmosis, ultrafiltration and electrodialysis.
(4) Deep filter: the use of a particulate filter, such as quartz sand, anthracite. Due to the porosity, the wastewater passes through the filter layer of a certain depth between the particle filter, i.e. entrapping suspended solids. It is different from the three types of surface or shallow filtration process, such filters known as depth filtration, filtration abbreviation.