AWWA JAW26145

An increasing number of chlorinated by-products resulting from disinfection practices will be regulated as a result of the 1986 amendments to the Safe Drinking Water Act. Consequently, ozone is being employed more frequently for the control of trihalomethanes and other disinfection by-products (DBPs). To evaluate the impact of ozonation on the formation and control of DBPs in drinking water, studies were conducted at four utilities. Treatment modifications were made on the process trains at each plant either at full or pilot scale to incorporate ozone in the treatment process. Samples were collected before and after ozone was added to the treatment train and were analyzed for selected DBPs. In general, treatment trains that employed ozonation followed by chloramination were the most effective in reducing trihalomethanes and other halogenated DBPs. Increases were found, however, in some compounds such as chloropicrin and aldehydes. Includes 30 references, tables, figures.