Abstract
Filtered water from a water treatment plant and aqueous solutions of model compounds for humic substance were chlorinated. Trihalomethans (THM), chloral hydrate (CH), dichloroacetic acid (DCA), and trichloroacetic acid (TCA), which were produced in the chlorination reaction, were determined in each case. THM were determined by ECD-GC. A method using GC/MS or ECD-GC was developed for determining CH, DCA, and TCA.
When the filtered water from Ushikubi water treatment plant was chorinated at pH7 and at 20°C, the total of CH, DCA, and TCA was compared to the total amount of THM. The quantity of these chlorinated products increased with time and the ratio to the total organic halide reached to 38% (as chlorine equivalent) after 6 days.
In the chlorination using 1, 3-dihydroxybenzene, 1, 3-dihydroxynaphthalene, or their derivatives as the model compound, the main product was always chloroform. On the other hand, TCA was often produced as the main species when other monohydroxy or dihydroxy aromatic compounds were chlorinated.
