The pretreatment of purified water refers to a preliminary treatment which is carried out in advance before the water purification treatment so that the purification of water is effective. So that the pretreatment of pure water are those who put it? 1. Precipitation: Treatment with large volumes, low flow rates of natural precipitation, such as sedimentation tanks. 2. Coagulation: the use of iron, aluminum, polymer and other coagulants, and impurities in the water through the flocculation and bridging role in the formation of large particles of sediment, and then through other equipment, to be removed. 3. Filtration: the water will be treated, through a special filter material with the device, cut off the impurities in the water, to be removed. 4. Softening: the use of chemical or cation exchange resin method, the water of calcium, magnesium, iron ions removed. 5. Disinfection: the addition of pharmaceuticals or the use of ultraviolet light, ozone and other methods to eliminate water in the micro-organisms, bacteria, etc. The above five points is pure water pretreatment of the five methods, concerned about Henan White's Industry, to bring you more water treatment related know how.