Effects of reaction conditions on the oxidation efficiency in the Fenton process

The purpose of this study is to efficiently operate Fenton's oxidation proc ess with quantitative analysis of the amount of the organic substances remo ved by oxidation and coagulation in treatment of the non-biodegradable land fill leachate by Fenton's reagents. The sample used was the biologically tr eated leachate in the Kimpo metropolitan landfill site in Korea and its GOD , BOD5, NH3-N and Cl- concentrations were about 1500, 30, 1300 and 1500 mg/ l, respectively. The COD removal by oxidation of the organic substances wit h hydrogen peroxide was most efficient in the pH range of 2.5-4. However, i t drastically decreased according to the pH value above 5. The COD removal efficiency by coagulation increased with the increase of the ferrous sulfat e dosage, but the overall efficiency over a minimum dosage of 500 mg/l was scarcely changed. The efficiency of hydrogen peroxide actually used in the oxidation of the organic substances was only about 45%. The optimum range o f the coagulation pH to maximize the COD removal efficiency by coagulation was 3-6, but that was slightly lower than the pH range of 6-9 generally kno wn in the literature. (C) 2000 Elsevier Science Ltd. All rights reserved.