Method for the degradation of harmful substances in water by means of hydrogen peroxide under UV irradiation

A method for degradation of a harmful substance in water, comprising:

• adding a sufficient quantity of hydrogen peroxide to the water, wherein the hydrogen peroxide provides a source of hydroxyl radicals, so as to achieve a desired degree of degradation of the harmful substance contained in the water;
• passing the water and hydrogen peroxide through a reaction zone;
• irradiating the water and hydrogen peroxide in the reaction zone with ultraviolet radiation from at least one ultraviolet radiator, such that the hydrogen peroxide forms hydroxyl radicals which oxidize the harmful substance in the water, and wherein a ratio of the non-irradiated volume to the irradiated volume, as determined at a wavelength of 265 nm, is greater than 2;
• wherein the reaction zone has a specific volume of at least 40 liters per kilowatt of electric power of the at least one ultraviolet radiator, and wherein an amount of water treated per hour is equivalent to 0.5 to 5 times an intrinsic volume of the reaction zone.