Treatment of landfill leachate from Fez city (Morocco) using Fenton and photo-Fenton processes

Abstract

In the present work, the treatment of a leachate from Fez city urban sanitary landfill (Morocco) was evaluated using different advanced oxidation processes (AOPs), such as, Fenton (Fe2+/H2O2), photo-Fenton (Fe2+/H2O2/UV-A), UV-A and UV-A/H2O2. The leachate was characterized by high chemical oxygen demand (COD), low biodegradability and intense dark color. The treatment efficiency was evaluated as a function of different operation variables ([H2O2], [Fe2+], UV-A irradiance), resulting in COD removals between 30% and 77%. Removal efficiencies decreased in the following order: photo-Fenton> Fenton> UV-A/H2O2> UV-A. Thus, a detailed experimental analysis was carried out to analyze the effect of hydrogen peroxide and iron concentration in the photo-Fenton process. It was observed that: (a) COD removal ranged from 4% to 84% depending on the H2O2 dose, (b) COD removal increased by adding the H2O2 dose in multiple steps (84%) and (c) iron concentration corresponding to a Fe2+/COD mass ratio = 0.35 was found to be the most favorable. At optimum conditions, COD removal was 70% and 84% for Fenton and photo–Fenton processes, respectively. In addition, the optimum contact time for both processes was 1 hr. Finally, the results of this study showed that the Fenton and photo-Fenton process is capable of achieving high levels of COD removal.