Comparison of Disinfection Byproducts from Using Chlorine and Chlorine Dioxide in Drinking Water Distribution Systems

We have examined and compared disinfection by-product (DBP) formation from using chlorine and chlorine dioxide in disinfection treatment of several drinking waters with different composition, structure and content of dissolved organic matter and different content of bromide and total dissolved nitrogen. In addition, for different treatment conditions such as the disinfectant dose applied, the temperature of the water samples and the reaction time, the decay of the disinfectant was investigated and corresponding bulk decay coefficient determined. As it might have been expected, chlorine dioxide produces much less halogenated DBPs, and higher levels of bromide in water result with significant bromine substitution in some DBPs. Genotoxicity in samples of disinfected water was evaluated in human lymphocytes. The results of the Comet test showed that genotoxic potential in water samples differ considerably in relation to the type of disinfectant used, dose applied and the quality of the water.