Abstract: This invention presents the set-up of a heterogeneous photo-Fenton system for the abatement of organic pollutants in liquid wastewater by means of heterogeneous perovskite-based catalysts, both in powder and in structured form. The proposed method employs, preferably, structured honeycomb monoliths consisting of a perovskite-based material (unsupported catalyst), or structured honeycomb monoliths made of a refractory carrier or a foam impregnated with a solution of salts corresponding to the desired perovskite (supported catalyst). The removal of organic substances is carried out at room temperature and atmospheric pressure, through an oxidation to gaseous CO2. The perovskite-based catalyst, in structured form, is more efficient in the degradation of organic pollutants than a homogeneous photo-Fenton catalyst. It allows to enlarge the operative range of pH in comparison to the limited operative range of pH of the homogeneous system, without the formation of sludge.