Studies On The Formation Of Disinfection By-products (DBPs) In Simulation Chlorination For Drinking-water

In the present work, the differences of organic types, properties and functional groups in chlorine reaction were considered. Some micro-molecular organics which was hard to remove and the most easy to format trihalomethanes(THMs) with chlorine, some aromatic organics which have similar structure with humic acid and actual water were chose. The influences of the reaction time, pH level, chlorine dose, divalent metal ions and Br ion on the formation of trihalomethanes (THMs) and chloral hydrate (CH) were investigated. The results indicate that the formation of THM for micro-molecular organics increased with the increasing reaction time; CH formation was not consistent rule. THM formation initially increased and then decreased with the increasing pH level; CH formation of malic and humic acid initially increased and then decreased, CH formation of citric acid decreased sharply and then became constant. THM and CH formation increased with the increasing chlorine dose. The influence on THM and CH enhancement in proper order is as follows: Cu2+> Mg2+> Ca2+. The contents and types of disinfection by-products(DBPs) were impacted by Br ion, the total trihalomethanes(TTHM) increased the increasing Br concentration, the chloromethane turned to Br-Cl compounds, then turned to bromomethane, the finally product was CHBr3. The difference formation of THM and CH and the chlorination speed owing to different aromatic organics. Single substituents organics with electron withdrawing group and weakly electron donor group were easy to format THM. THM was more easily formated by double substituents organic. CHCl3concentration decreased sharply by low concentration Br-, TTHM increased. The actual water in south China showed regularity with the different chlorinated condition, it offered basic technology provide for drinking water treatment systems.