This study is designed to evaluate the feasibility of using hydrogen peroxide to reduce the trihalomethanes formation potential (THMFP) in ferrous coagulation process. A commercial humic acid is employed as THMs precursor. The results indicate that the optimum pHs for both ferrous coagulation and Fenton's preoxidation processes are ranged between 4.0-5.0 and 2.0-4.0, respectively. Using hydrogen peroxide can markedly enhance the ferrous coagulation, which ensures THMFP reduction. The increases of ferrous coagulation efficiency also reduces the ferrous dosage. In Fenton's processes, KMnO4 consumption and THMFP residuals are higher in coagulation step than in preoxidation step. This indicates that the THMFP reduction is mainly accomplished at the preoxidation step. Furthermore, the residual KMnO4 consumption is highly correlated with the residual THMFP. It is suggested that KMnO4 consumption can be used as a better surrogate than A254 for the THMFP in ferrous coagulated waters.
