Removal algae with different coagulants from micro-polluted water in Liuxi River.

Removal of algae and turbidity from raw water of Liuxi River was studied by using aluminum sulfate (AS),poly aluminum ferric chloride (PFAC),poly aluminum sulfate (PAS),poly ferric sulfate (PFS) in summer and autumn.The effect of different coagulants,dosages of coagulants,pH and temperature of raw water on coagulative efficiency were investigated.The charge neutrality capability of coagulants,structure and morphological of floc were characterized by zeta potential meter and micrograph.The coagulation efficiency of AS was the best when pH ranged from 6~8,water temperature was higher than 15℃,algae and turbidity were 1.14×107~4.10×107cells/L and 27~38NTU respctively.The removal rates of algae and turbidity can even reach 80% and 89% respctively when the AS dosage was 3mg/L.The coagulative efficiency of other coagulations were PFACPASPFS.Further more,the coagulative performance of PAS and PFAC were better than others when the temperature of raw water was low in winter.