The role of PAC and its basic performance PAC flocculation performance as follows: a, colloidal substances in the water strong electric neutralization. b, hydrolyzate of water suspended solids excellent bridging adsorption. c, the selective adsorption of dissolved substances. Poly aluminum chloride performance: a, purified water better than aluminum sulfate flocculant, water purification costs compared with low 15-30%. b, rapid formation of flocs, settling speed, processing capacity than the traditional products such as aluminum sulfate. c, water consumption alkalinity lower than a variety of inorganic flocculant, which can not vote or less cast alkali. d, to adapt to the source water PH5.0-9.0 range can be condensed. e, corrosive, good operating conditions. f, solubility better than aluminum sulfate. g, treatment of salt in the water increased less conducive to ion exchange treatment and high purity water. h, adaptability to source water temperature is superior to inorganic flocculant such as aluminum sulfate.