Removal of Geosmin by Combined Treatment of PAC and Intermediate Chlorination in the Conventional WTP

In this study, the effective treatment reducing geosmin and dosage of PAC was suggested when taste & odor compounds flow in.The removal efficiency of geosmin was evaluated with types of chlorination.In case of low geosmin concentration below 25 ng/L, removal efficiency of geosmin was estimated at 46% by combined treatment of pre and intermediate-chlorination. But, in the exclusive intermediate-chlorination treatment, removal efficiency of geosmin was increased to 57%.In the medium geosmin concentration (25~79 ng/L), removal efficiency of geosmin was estimated at 59% by combined treatment.But, in the exclusive intermediate-chlorination treatment, removal efficiency of geosmin was increased to 87%.When high geosmin concentration above 80 ng/L flows in, removal efficiency of geosmin was estimated at 69% by combined treatment.However, in the exclusive intermediatechlorination treatment, removal efficiency of geosmin was increased to 95%.Then, the exclusive intermediate-chlorination has an important effect on removal of geosmin.After correlation of geosmin concentration and dosage of PAC was analyzed, the coefficient of determination was estimated at 0.96.And, the proper PAC dosage chart was proposed.Also, at a initial occurrence of geosmin, when the combined treatment by intermediate-chlorination and PAC was applied, particle-bound geosmin should be removed continuously.Finally, it is proved that the combined treatment was effective to remove the geosmin by threshold levels as well as to reduce the dosage of PAC.