Landfill leachates contain various refractory contaminants that pose potential threats to the environment and human health. In this study, Cu/Mg/Al-chitosan was synthesized by decorating chitosan with Cu (0.89 mmol/L), Mg (4 mmol/L), and Al (2 mmol/L) using a precipitation method. The catalytic potential of Cu/Mg/Al-chitosan for ozonation of real landfill leachate was examined (COD = 40,700 mg/L; BOD5 = 2100 mg/L; pH 9.1; BOD5/COD = 0.052). A significant catalytic potential of 51% was obtained for chemical oxygen demand (COD) removal in the catalytic ozonation process (COP) with 20 mg/L of catalyst and a reaction time of 50 min. The COD removal rate of the COP with Cu/Mg/Al-chitosan was 5.3 and 3.77 times greater than that with the established catalysts activated carbon and MgO, respectively. A pseudo first order kinetic model fit the heterogeneous decays of ozone the best. The tert-butanol was employed as a radical scavenger in the experiments. GC/MS analysis was used to determine the organic compounds before and after the treatment. Thus, Cu/Mg/Al-chitosan is a promising and affordable catalyst for use in COPs to attenuate the COD of landfill leachates. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.