Simultaneous removal of COD and color from municipal landfill leachate using Ozone/Zinc Sulphate oxidation process

Municipal landfill leachate generated from aged sites requires an efficient treatment to minimize the high level of refractory organic matters prior to final discharge. In the current study, the performance of combined ozonation and Zinc sulfate (ZnSO4) for anaerobic stabilized leachate treatment was investigated. The efficiency of Zn dosage [COD0/Zn ratio (g/g)], pH, and ozonation time was evaluated. The optimal removal efficiencies for COD and color were 90% and 99%, respectively at 1 g/6 g ZnSO4 dosage (COD0/Zn), pH 4, and 180 min reaction time. However, the performance of O3/Zn oxidation process in removing ammoniacal nitrogen from leachate was not efficient as less than 5% removal for ammonia was obtained. The results revealed that the performance of the new catalytic ozone method (i.e., O3/Zn) in removing removal organic substances from leachate was higher than another related oxidation process such as O3/Fenton and O3/persulfate.