A method for wet oxidation of organic material, characterized by the utilization of the heat generated by the oxidation of the pollutants that are present in a first preheated wastewater introduced at the base of the reactor in order to provide the energy sufficient to trigger the oxidation reaction in a second wastewater, which is introduced in a higher point with respect to the base of the reactor and has a temperature that is proximate to the ambient temperature and a high concentration of pollutants; and an apparatus adapted to provide this innovative wet oxidation method.