A study was conducted to determine the effects of ozonation on the removal of iron(II) and manganese(II) at different pH values in a pure water system. It has been found that the rates of oxidation of iron(II) and manganese(II) follow a 7.ero‐order reaction. The respective values of detention time and applied ozone dosage for removal of 4 mg/L of iron(II) were 10–15 min and 3–5 mg/L, as compared to 20–30 min and 4–6 mg/L for the removal of 4 mg/L of manganese(II). No iron(II) and manganese(II) were detected in the pure water system above the pH values of 7 and 9, respectively.