Optimization of US-Electropersulfate Process for Leachate Treatment by Response Surface Methodology

Abstract

Background and Objectives: Chemical Oxidation Demand (COD) is an important parameter in treatment of leachate. Leachate from solid waste has high pollutants that must be treated before discharge to environment. The aim of this study was optimization of US-Electro/persulfate process, predicate of optimum conditions by RSM for landfill leachate treatment. Methods: In this experimental study, a sonochemical reactor with one liter volume that equipped with 40 KHz and two Iron electrodes as an anode and two Copper electrodes as a cathode that connected to direct current supply source was used. In the final step of study, pH (2-4), S2O8 2-(1-2 g/L), direct electrical current (1.5-3 A) and reaction time parameters as an independent parameters were studied. In optimum condition, corrosion of the electrodes in anode and energy consumption were measured. Sludge properties before and after the process were analyzed by SEM/EDAX and FT-IR spectroscopy. Results: By using this software (design Expert), the optimum condition was done at PH=3.41, S2O8 2-dose=1.2 g/L, current density=2.41 A, and reaction time were 70 min. In this condition the efficiency of COD removal was 75 %. The R-squared and Adj R-squared process was 0.78 and 0.88 respectively. The electrodes corrosion in optimum condition were 0.77 g and energy consumption was 9.23 kW/kg COD. The results of analysis indicate that changes in sludge during the process has happened and elements structure in leachate has observed, the most obvious oxygen and iron increased in sludge after the process. Conclusion:The US-Electro/persulfate has a good efficiency in COD removal and with this model can be tested with a few run and high accuracy to optimize the process.