Cationic polyelectrolytes as primary coagulants for removing trihalomethane precursors

Abstract

Four cationic polymers were tested as sole coagulants for removing trihalomethane precursors from synthetic and natural waters. Waters synthesized from humic acid were more amenable to polymer coagulation than those synthesized from fulvic acid. The presence of kaolinite appeared to improve removal of trihalomethane formation potential (THMFP) from these waters. In general, the performances of the polymers were comparable. For the natural waters, the effectiveness of polymer coagulation in THMFP reduction varied as a function of raw water source. Ambient pH of the water appeared to influence polymer performance. For both types of water, the reductions in THMFP were generally greater than the corresponding decreases in total organic carbon.