Optimization of persulfate/iron(II)/UV-A irradiation process for the treatment of landfill leachate from Fez City (Morocco)

The objective of this study is to investigate the efficiency of the advanced oxidation process using persulfate ions S2O82- (PS), Fe2+, and UV-A irradiation for the treatment of stabilized leachate from the urban sanitary landfill of Fez city (Morocco). In fact, in the presence of an activating agent, S2O82- generates sulfate radicals (SO4-.) which are powerful oxidizers for organic matter. The effect of reaction time, PS and Fe2+ dosage on the raw landfill leachate treatment was evaluated to define the optimum operational conditions according to chemical oxygen demand (COD) and color removal. Hence, the optimization of these process parameters led to a maximal removal of COD (70%) and color (94%) using S2O82- dose = 14,000 mg L-1, Fe2+ dose = 1600 mg L-1, and pH = 3 under 60 min of UV-A irradiation. The application of UV-A had a positive effect on the treatment efficiency, PS/Fe2+/UV-A has indeed enhanced COD removal by (+10%) compared with PS/Fe2+ only. The results of this study showed that the oxidative system (PS/Fe2+/UV-A) can achieve a high level of COD and color removal from landfill leachate. Consequently, the high efficiency, the easy use, and the fast mechanism could make this system as a promising and alternative process for landfill leachate and wastewater treatment.