Landfill leachate post-treatment by the photoelectro-peroxone process using a baffled reactor

Abstract

As cities develop and the population grows, municipal waste management has become increasingly important. Sanitary landfilling is one of the most prevalent waste management methods, which produces leachate. Due to the presence of various pollutants in leachate, its leakage into water bodies and soil will cause many serious problems, such as public health threats and carcinogenesis. One of the novel advanced oxidation processes (AOPs) for treating leachate is the photoelectro-peroxone (PEP), a combination of ozonation, electrochemical production of hydrogen peroxide, and ultraviolet (UV) irradiation processes. This study aimed to post-treatment of leachate using the PEP process on a laboratory scale with an up-down, and vice versa, baffled reactor for the first time. Based on the obtained results, the ozonation rate of 0.82 gr/hr.L, the electric current intensity of 0.75 A, initial pH of 8.6 (natural leachate pH), UV radiation power of 24 W, and the anode-to-cathode surface ratio of 1:1 with a total area of 37.8 cm2 for each anode and cathode were chosen as the optimal conditions. After 240 min under these conditions, COD, TOC, and color removal efficiencies of 68.8 %, 61.4 %, and 100 % were obtained, respectively. Furthermore, the control experiments showed that the PEP process had a significantly synergistic effect on degrading contaminants in the leachate, improving its efficiency over the electro-peroxone (EP), UV/O3, and sole ozonation processes.