An experimental study was conducted to investigate the effects of chlorine dioxide and ozone on reduction of THM(trihalomethane) formation. Precursor concentration, chlorine concentration, reaction time, pH, and temperature were governing compornents of THM formation. When other conditions are constant, THM formation increased linearly with precursor concentration increased. THM formation increased when pH increased from 5 to 9. In combined treatment with chlorine and chlorine dioxide, chlorine treatment after chlorine dioxide treatment made less THM than any other case does. Ozonation reduced THMFP(THM formation potential) of THM precursor. THMFP decreased exponentially with reaction time increased. Also biodegradability of humic acid was enhanced by ozonation.

We have been proposed model equation which is able to predict the trihalomethane producing concentration formation, that is one of byproduct, in the water treatment processes. In proposed model, the effects of trihalomethane factors like chlorine contact time, pH, temperature, TOC and UV-254 are considered. The concentration of the trihalomethane produced is proportion to the contact with chlorine, pH of water, temperature of water TOC and UV-254, respectively. This proposed model could be predicted the formed concentration of trihalomethanes by trihalomethane factors.

SPME device was applied to determine the THM in an aqueous solution. The 6 kinds of THM was quantitatively detemined by using GC-ECD which has the sample extracted on the SPME fiber from an aqueous solution for 10 min. The THM components were well separated from CHCl_3 to the last CHBr_3 within 13 mans at the condition. 6 kinds of the volatile halogenated organic compounds: CHCl_3, CHBrCl_2, CHBr_2Cl, CHCl_3, C_2Cl_4, and CHBr_3, showed well defined calibration graph with good linearity from a few ppb level up to several tens of ppb concentration. CHBr_2Cl and C_2Cl_4, were detected from a few samples among the 10 of river samples. CHCl_3, however, was detected in 4 sea water samples with the highest of 10 ppb among the polluted 6 positions. Trace level of CHBr_2Cl and few ppb level of CHBr_3 were also detected at the other two sample stations. Most of the 13 rain water samples collected from 6 sampling stations were contained ppb level of CHCl_3, and also CHBr_2Cl, and C_2Cl_4 were only detected at trace level at a few rain samples among them. We could recognize the fact that our air and water environment has already been contaminated by certain volatile halogenated organic compounds through this study.