Evaluation of the main parameters affecting the Fenton oxidation process in municipal landfill leachate treatment

The aim of this study was to investigate the use of the Fenton oxidation process for treating leachate from a municipal solid waste landfill collected from Aradkooh site, Tehran, Iran. The focus of the study was to evaluate the process performance by COD removal efficiency. Results indicate that the optimum amounts of oxidation parameters in the Fenton process were as follows: oxidation pH = 4, H2O2/Fe2+ molar ratio = 4-5, Fe2+ ion dosage = 11 200-19 600mg L-1 and oxidation time = 20-30 min. In addition, the maximum amount of COD that it was possible to remove by the Fenton process was about 47% of the initial value (i.e. 35 000 mg L-1). This level of removal was achieved by using 19 600mg of Fe2+ per litre of leachate with (HO2)-O-2/Fe2+ molar ratio of 4.5, for the following operational conditions: oxidation pH = 4; coagulation pH = 7.5; oxidation time = 100 min; coagulation time 30 min. Furthermore, it was found that 90% of oxidation occurred during the first 20 min of the oxidation stage. All the experiments, except for oxidation time, were conducted in two rounds for better optimization.