Fig. 3 shows the effect of initial pH different coagulants at optimal dosage in terms of residual turbidity,UV254, DOC and CODMn removal. For PACl, residual turbidity of the effluent was on the decline trend in the test range of pH, and dropped below 1 NTU when the pH increased to 8 and above. Obviously, PACl had a significantly higher turbidity removal than TiCl4 in acidic conditions.