摘要：

This study investigates the bactericidal efficiency of the different kind of disinfectants as well as their effects on trihalomethane (THM) formation in the reaction with humic substances in the natural water. The application of chlorine as a disinfectant has caused much awareness and concern among health authorities in Thailand because it formed THM which are carcinogenic. Analysis revealed that with the same initial dosage of chlorine, the level of THM concentration will increase with increasing level of THM precursors. Alternative chemical disinfectants such as chlorine dioxide, ozone and peroxone (ozone + hydrogen peroxide) were also investigated. Ozone and peroxone were not only found to be very effective in Coliform inactivation hut also were good agent in controlling THM formation through maximizing the total organic carbon (TOC) removal. For 99.9% Coliform inactivation, the minimum chlorine dosage required was 3 mg/L whereas the required dosage for ozone and peroxone were only 0.6 and 0.34 mg/L respectively. Peroxone application can also increase the THM removal by ozone to 20-30%.

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