A kinetic study was carried out to determine the effects of ozonation on the removal of iron(II) and manganese(II) at different pH values in the presence of model organic compounds possessing structural features of humic acid. The order of reaction for ozone oxidation of iron (II) in the presence of different model organic compounds varied from zero to three. In some cases the order of reaction appeared to be above three indicating the reaction to be too fast. The total organic carbon (TOC) decreased considerably as a result of ozonation.