Effects of AOP Pre-treatment on DBPs Formations

Chlorination disinfection is a common water treatment process in Taiwan, generating toxic chlorinated disinfection by-products (DBPs). Unfortunately, Br-DBPs are also formed in presence of bromide. Cl-DBPs and Br-DBPs have received much public concern about their different health effects on carcinogenicity and reproduction damages. Therefore, the objective of this study is to evaluate bromide concentration, pH and precursor structures in drinking water to determine their influences on formation and distribution of THM and HAA. And this study also concerned about the changes of influencing factors and DBPFP in UV/H2O2 oxidation.
Aromatic and aliphatic precursors and different bromide concentration were evaluated for the distribution of Cl-DBP and Br-DBP under chlorination at pH 7 and pH 9. Steric hindrance limited the aromatic precursors to Cl-DBPs under whole conditions. The aliphatic precursors tended to form Br-DBPs. Besides, the aromatic precursors were more reactive at pH 7, and the aliphatic one at pH 9.
Tai lake water (Kinmen, Taiwan) and humic acids were selected in this study. In the UV/H2O2 process, THMFP or HAAFP increased within 10 min of irradiation and began to decrease after 30 min. OH-radicals seemed to increase DBPFP because which was not observed using UV irradiation without hydrogen peroxide. The bromide concentration remained stable and no bromate was formed under all irradiation time. The optimum effectiveness of UV/H2O2 process should be reached in application of bromide-rich Kinmen water.