Catalytic formulations based on manganese oxides supported on inorganic oxides were developed for the treatment of methylamine-containing aqueous effluents via catalytic wet air oxidation (CWAO). Under the applied reaction conditions (190 degrees C, 50 bar total pressure) in the presence of heterogeneous beta-MnO2-supported catalysts, formate and ammonium ions were detected as primary products. As the reaction proceeded, a complete mineralization of formate ions was observed while ammonium ions accumulated in the reaction media. The catalytic formulations elaborated in this work were shown to be stable under the applied reaction conditions without any significant leaching of the active phase. (C) 2015 Elsevier B.V. All rights reserved.