Pollution of aquatic water became one serious environmental problem. However photochemical processes have been widely used in water decontamination process whether coupled or not with Ultraviolet (UV) light. The aim of the following study is to test the ability of some photochemical processes (photolysis at 254 nm and some Advanced Oxidation Technics (AOTs) in absence of light (Fenton) and in its presence (photo-Fenton) to eliminate the Bromocresol Purple (BCP, anionic structure) in aqueous solution. The obtained results showed that the best conditions were found to be pH of 3, hydrogen peroxide-to-iron (II) molar ratio of 10:1 and artificial light (254 nm and 365 nm). Influence of some parameters was also studied like: pH, concentration of H2O2 and the irradiation wavelength. The efficiency of the processes studied decreases in the following order: Photo-Fenton 254 nm>Fenton>photolysis 254 nm.