The polymerization of ferric sulfate turbidity in the application of the effect is very good, and with no residual ferric ion reaction completely suspended solids completely removed. 3, Polyferric sulfate is better than PAC, phosphorus in water will reduce the flocculation reaction of aluminum salt, the dosage of both agents will reduce the degree of alkalinity of water, but polyaluminum chloride due to alkali The bottom is higher than the polymerization of ferric sulfate Polyferric sulfate is the dosage of more COD removal rate is higher 1. In addition to polymeric ferric sulfate can handle general heavy metal ions, but also to COD, BOD and water color Very good removal effect, resulting in poor precipitation, the temperature can not be removed. Removal of other impurities and to the turbidity function should also be much better than polyaluminum chloride. 2, Polyaluminum chloride treatment process on the impact of changes in water temperature, the temperature is low, the flocculation will slow down, the formation of alum also becomes smaller, the removal rate of BOD up to 93% or more