TOC Removal by Coagulation and Softening

Chlorination of water containing organic compounds results in generation of undesired chlorinated hydrocarbons. Enhanced removal of precursors present in raw water is one of the viable options for effectively reducing the formation potential of undesired reaction products. Total organic carbon (TOC) and turbidity removal by Fe (III) coagulation under low pH, and coagulation under high pH with Fe (III) combined with lime softening were investigated for a lake water. The results of jar tests showed that low pH coagulation removed 42% TOC and 96% turbidity at an optimum pH of 6.3 when 20 mg/L Fe (III) was used as a coagulant. High pH coagulation with lime softening removed about 81% TOC and 97% turbidity at pH 10.3 when 9.5 mg/L Fe (III) was used as a primary coagulant.