Optimization of leachate treatment using persulfate/H₂O₂ based advanced oxidation process: case study: Deir El-Balah Landfill Site, Gaza Strip, Palestine

The objective of this study was to investigate the performance of employing H₂O₂ reagent in persulfate activation to treat stabilized landfill leachate. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as persulfate and H₂O₂ dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following two responses proved to be significant with very low probabilities (<0.0001): chemical oxygen demand (COD) and NH₃-N removal. The obtained optimum conditions included a reaction time of 116 min, 4.97 g S₂O₈²⁻, 7.29 g H₂O₂ dosage and pH 11. The experimental results were corresponding well with predicted models (COD and NH₃-N removal rates of 81% and 83%, respectively). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as persulfate only and H₂O₂ only, to evaluate its effectiveness. The combined method (i.e., /S₂O₈²⁻/H₂O₂) achieved higher removal efficiencies for COD and NH₃-N compared with other studied applications.