UV photo-oxidation system for oxidizing contaminates in a contaminated fluid on the basis of hydrogen peroxide comprising: a cylindrical housing for containing a contaminated fluid, the housing comprising a first base side and a second base side , the first base side and second base side forming two opposite ends of the housing ; said housing comprising a main inlet and an outlet both at the first base side , said main inlet being located on or close to the centre of the first base side ; a plurality of tube-shaped UV light sources mounted in said housing , the longitudinal axis of each of the plurality of tube-shaped UV light sources arranged substantially parallel to the longitudinal axis of the cylindrical housing ; the plurality of tube-shaped UV light sources including a first set of UV sources mounted close to the longitudinal axis of the housing and a second set of UV sources mounted away from the longitudinal axis , wherein, when in use, the first set of UV light sources form a first region in said housing of a first average UV light intensity and the second set of UV light sources form a second region of a second average UV light intensity arranged around the first region ; a pumping system connected via a pipe system to the inlet for pumping a contaminated fluid under force in said housing ; an oxidation agent release system including a container comprising hydrogen peroxide connected via a controllable valve to said pipe system for mixing hydrogen peroxide with the contaminated fluid before the fluid is injected into the housing via the inlet ; wherein the main inlet comprises a nozzle for injecting the mixture of hydrogen peroxide and the contaminated fluid under high pressure into the cylindrical housing in a direction towards the second base side . a cylindrical housing for containing a contaminated fluid, the housing comprising a first base side and a second base side , the first base side and second base side forming two opposite ends of the housing ; said housing comprising a main inlet and an outlet both at the first base side , said main inlet being located on or close to the centre of the first base side ; a plurality of tube-shaped UV light sources mounted in said housing , the longitudinal axis of each of the plurality of tube-shaped UV light sources arranged substantially parallel to the longitudinal axis of the cylindrical housing ; the plurality of tube-shaped UV light sources including a first set of UV sources mounted close to the longitudinal axis of the housing and a second set of UV sources mounted away from the longitudinal axis , wherein, when in use, the first set of UV light sources form a first region in said housing of a first average UV light intensity and the second set of UV light sources form a second region of a second average UV light intensity arranged around the first region ; a pumping system connected via a pipe system to the inlet for pumping a contaminated fluid under force in said housing ; an oxidation agent release system including a container comprising hydrogen peroxide connected via a controllable valve to said pipe system for mixing hydrogen peroxide with the contaminated fluid before the fluid is injected into the housing via the inlet ; wherein the main inlet comprises a nozzle for injecting the mixture of hydrogen peroxide and the contaminated fluid under high pressure into the cylindrical housing in a direction towards the second base side . <EOS>