- P-ISSN 1225-0163
- E-ISSN 2288-8985
Chemical degradation of aqueous humic acid by ozonation was studied with respect to the direct reactions of ozone and the indirect reactions due to its preliminary decomposition to secondary oxidant, OH radical. This was characterized by analyzing TOC, <TEX>$UV_{254}$</TEX> and ozone consumption measured in different experimental conditions in which ozone reacted in the presence of various concentrations of <TEX>$H_2O_2$</TEX> and <TEX>$HCO_3{^-}$</TEX> concentrations ranging from 20 to 100 mg/L. and different pH (5-9). The results suggest that the TOC removal is mainly dependent on indirect reactions of OH radical whereas <TEX>$UV_{254}$</TEX> reduction is mainly dependent on direct reactions of ozone with humic acid molecules. It has been also found that ozone consumption was most likely to be affected by pH and alkalinity in the solution.