Abstract: Reactor for the optimized ozonization of water intended for human consumption, in which the direct oxidizing action of the ozone is supplemented by the radical oxidizing action of the ozone, the latter being intensified by the introduction of hydrogen peroxide, characterized in that it comprises three contact tanks arranged in series: a first contact tank receiving the water to be treated and intended for the direct and rapid oxidizing action by the ozone which is introduced into the said tank and brought into contact with the liquid to be treated; a second contact tank intended to ensure the disinfection of the liquid and into which is injected the quantity of ozone necessary to maintain in the liquid to be treated the residual ozone concentration necessary for the disinfection of the water; and a third contact tank intended to ensure the radical action of the ozone, into which there is injected, besides the ozone, a quantity of hydrogen peroxide intended to increase the quantity of OH radicals available for