Disinfection Efficiency and Formation of Disinfection Byproducts in Jordanian Drinking Water Treated with Chlorine Dioxide

In this study factors affecting disinfection efficiency and formation of disinfection byproducts (DBPs) in water treated with chlorine dioxide (ClO2) were investigated. The amount of trihalomethanes THM and haloacetic acids HAA and chlorite ion was determined in samples collected from three different sources in Jordan: Deir Alla surface water, Wadi Al Sir springs, and Yajooz spring. The amounts of THM and HAA in real treatment plants were determined. Focus on chlorite ion as a major DBP in ClO2 treatment was made to investigate the factor that affects its concentration. This study aims also to identify new DBPs associated with ClO2 disinfection. Results show that chlorite ion has its highest formation at higher ClO2 dose, TOC, pH and temperature. Analysis of real samples shows that using ClO2 for disinfection leads to formation of smaller amounts of THM and HAA compared to chlorine gas. Among the three investigated water sources in Jordan, Deir Alla water was found to have the highest formation of DBPs upon treatment with ClO2. New DBPs were identified for the first time in water treated with ClO2 including some halogenated compounds, carboxylic acids and some aldehydes and ketones. Disinfection efficiency of ClO2 was found to increase by increasing ClO2. Disinfection efficiency was found to be the lowest at temperature of 30°C and pH= 7, deviation from these values result in an increase in the efficiency of disinfection.