Chlorine dioxide (ClO2) is effective as both a disinfectant and an oxidant in water and wastewater treatment. Its selective reactivity makes chlorine dioxide a powerful oxidizing agent useful in many water treating applications for which chlorine and other oxidizing agents are unsuitable. Unlike chlorine, chlorine dioxide does not react with naturally occurring organic materials to form trihalomethanes (THMs). Chlorine dioxide aids in reducing the formation of TTHMs and haloacetic acids (HAA) by oxidizing precursors, and by allowing the point of chlorination to be moved farther downstream in the plant after coagulation, sedimentation, and filtration have reduced the quality of natural organic material (NOM).
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