DISINFECTION BY-PRODUCT FORMATION AND CONTROL BY OZONATION AND BIOTREATMENT

There is increasing interest in using ozone in water treatment because it is a strong disinfectant and is able to oxidize the precursors of some disinfection by-products (DBPs). However, ozonation itself produces DBPs, like aldehydes and ketones, and increases the concentration of bacterial nutrients by converting nonbiodegradable organic matter to more biodegradable compounds. In this study it was found that biotreatment of ozonated waters provided additional removal of precursors of total trihalomethanes, total haloacetic acids, chloropicrin, and total organic halides. Aldehydes are easily biodegradable. Piloting is recommended to determine site-specific ozone dosages and trade-offs in the formation of bromate and ozone DBPs and in the oxidation of chlorine DBP precursors.