AWWA WQTC52866

This study investigated the kinetics of trihalomethane (THM) formationand of chlorine consumption when natural organic matter (NOM) and organic compounds are chlorinated with an excess of chlorine. For NOM, THM precursors could be divided into fast and slowly reacting fractions. Long-term chlorine demand and the formation of slowly reacting THM precursors could be described by second-order kinetics. The influence of pretreatments (ultraviolet/visible irradiation, ozone, and chlorine dioxide) on chlorine demand and THM formation from NOM was also studied and discussed considering the reactivity of NOM on these oxidative treatments. The influence of the para-substituent on the rate constants was explained by considering the chlorination of chloroketones as the rate-limiting step for THM formation from phenols. Includes 26 references, table, figures.