Optimization of Fenton Oxidation Process for Biodegradability Enhancement of a Mature Landfill Leachate Using Response Surface Methodology

摘要

Biological methods are not appropriate for mature leachate (5-10 years) due to the presence of bio refractory materials and toxic compounds such as heavy metals. Now-a-days advanced oxidation processes such as Fenton reagent are used for the treatmentor biodegradability enhancement of refractory wastewater. In this study, the biodegradability enhancement of mature landfill leachate using Fenton oxidation process in lab scale has been investigated. To optimize Fenton reaction for biodegradability enhancement of leachate, Response surface methodology was used. Design Expert7 was used for statistical analysis of experimental data. The leachate samples have been taken from a 10 years old landfill and oxidation experiments in lab scale were done in different conditions from operational points of view (reaction time, pH, Hydrogen peroxide to Fe (II) ratio). The BOD5, COD, pH, H202, Fe2+ oxidation time were evaluated in 32 runs, 12 run as pretests and 20 run for optimization. Results from numerical optimization showed that in pH = 3.3, H202/Fe2+ = 15.82 and oxidation time of 130 min, COD removal, BOD5 and BOD5/COD ratio variation were 93.1, 0.56 and 0.49%, respectively. In optimal condition that BOD5/COD ratio will be 0.45, the oxidation time is 130 min, pH = 3-3.5 and H202/Fe2++ ratio = 14-17. This study indicates that Fenton oxidation enhances the biodegradability of the mature leachate. In the optimal condition of Fenton oxidation the BODB/COD ratio increased to 80 times greater than initial ratio.Results from experiments will agree to results from model. This agreement confirms accuracy and approach of obtained model.