Catalytic ozonation has recently gained significant attention as an effective process used for the removal of organics from water. Unfortunately, despite increasing research efforts in the field of catalytic ozonation and the introduction of new catalysts, the mechanisms of catalytic processes are still largely unknown. An understanding of the mechanisms of catalytic ozonation is vital in order to introduce this technique in water treatment at an industrial scale. Therefore, the main aim of this paper is to provide a short overview of catalytic processes, their recent advances and to identify major directions taken to understand mechanisms governing catalytic processes utilised in water and wastewater treatment. Catalytic ozonation is considered to belong to Advanced Oxidation Processes. However, the results published by several research groups indicate that not all catalytic processes utilise the power of hydroxyl radicals. (C) 2010 Elsevier B.V. All rights reserved.