Advanced oxidation comprises a range of similar but different chemical processes aimed at tackling pollution in water, air and soil. Over the past few decades, multidisciplinary research has been carried out to study a broad spectrum of topics such as understanding of process fundamentals, elucidation of kinetics and mechanisms, development of new materials, modelling, process integration and scale-up. This article identifies and discusses certain directions that seem to advance R&D on advanced oxidation for water/wastewater treatment. (c) 2008 Society of Chemical Industry.