In recent years, there has been a tremendous amount of research and development in the area of photocatalysis (heterogeneous and homogeneous), a process included in a special class of oxidation techniques defined as Advanced Oxidation Processes (AOPs), all characterized by the same chemical feature, production of (center dot)OH radicals. This paper reviews the use of sunlight to produce the (center dot)OH radicals by TiO(2) photocatalysis and photo-Fenton process. The reacting systems necessary for performing solar photocatalysis are described. The paper also summarizes most of the research carried out related to solar photocatalytic degradation of water contaminants, and how it could significantly contribute to the treatment of persistent toxic compounds. It outlines how to enhance the process efficiency by integration with biotreatment. Various solar reactors for photocatalytic water treatment mainly based on non-concentrating collectors built during the last few years are also described in detail in this review, as well as the use of the solar photocatalytic processes to inactivate microorganisms present in water, placing special emphasis on experimental systems made to optimize this disinfection technique. (C) 2009 Elsevier B.V. All rights reserved.