Potable Water Disinfection With Chlorine Dioxide

Chlorine dioxide (ClO2) is used as both a disinfectant and an oxidant in drinking water treatment. It has several distinct chemical advantages, which complement the traditional use of chlorine in potable water treatment.

Chlorine dioxide is highly effective in controlling waterborne pathogens while minimizing halogenated disinfection by-products. Chlorine dioxide is a broadspectrum microbiocide as effective as chlorine against viruses, bacteria, and fungi, and more effective than chlorine for the inactivation of the encysted parasites Giardia and Cryptosporidium. Chlorine dioxide is also an effective control strategy for taste, odor, color, iron, and manganese removal.

Chlorine dioxide is an extremely effective disinfectant and bactericide, equal or superior to chlorine on a mass dosage basis. Its efficacy has been well documented1 in the laboratory, in pilot studies and in full-scale studies using potable water and wastewater. Unlike chlorine, chlorine dioxide does not hydrolyze in water. Therefore, its germicidal activity is relatively constant over a broad pH range.