Landfill leachate treatment with Mn and Ce oxides impregnated GAC–ozone treatment process

•Eight types of Mn and Ce oxides impregnated GAC (MnCe-ACs) are developed.•Liquid film diffusion model is the best fitted model for MnCe-AC/O3 process.•MnCe-AC can be used for at least four cycles.•MnCe-AC/O3 can effectively remove organic compounds in landfill leachate.

Mn and Ce oxides impregnated granular activated carbons (MnCe-ACs) with ozone process (MnCe-AC/O3) are developed in this research for the treatment of landfill leachate. Most of the landfills fail to meet the COD discharge limit (200 mg/L) in Taiwan due to the high contents of humic acids (HAs) in leachates. Experimental results indicate that MnCe-AC/O3 processes could effectively remove HA, COD and TOC from landfill leachate. Parameters affecting the HAs removal efficiencies, such as types of MnCe-AC, pH, Cu(II), salts and t-butanol are investigated. In general, the removal efficiencies are in the order of MnCe-AC/O3 > GAC/O3 > O3 > MnCe-AC > GAC. MnCe-AC can be used for at least four cycles without significant reduction in performance. The main removal mechanisms of HAs by the MnCe-AC/O3 processes involved hydroxyl radicals based on the addition of t-butanol experiments. Liquid film diffusion model is the best fitted model for the MnCe-AC/O3 process. In conclusion, the MnCe-AC/O3 process can effectively remove organic compounds in landfill leachate to meet the requirement of COD discharge limit with minimal amount of sludge production.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideRemoval of HA, TOC and COD of landfill leachate by various treatment processes.