Abstract: A reactor assembly is provided for destroying contaminants in fluids by the application of UV radiation to promote the destruction of the contaminants. The reactor assembly has a vertically orientated reactor chamber with a centrally located lamp emitting UV radiation and operating at temperatures in excess of 700.degree. C. A protective sheath transparent to the UV radiation encloses the lamp and isolates the lamp from reactor interior to define thereby an annular reactor space through which fluids to be treated flow. The fluids flowing through the annular reactor space and along the sheath effect a cooling of the sheath due to lamp heating. The lamp has a terminal portion at each end thereof. Each terminal portion has a temperature sensitive component. The lamp is of a sufficient length to extend the terminals beyond the end portions of the reactor which has a length equal to or greater than the arc length of the lamp.

Abstract: A method of treating a liquid effluent or groundwater containing organic contaminants is provided. The liquid effluent or groundwater containing the organic contaminants is contacted with hydrogen peroxide and transition metal ions. The hydrogen peroxide and transition metal ions are present in effective amounts based on the concentration of the organic contaminants in the liquid effluent or groundwater. The liquid effluent or groundwater is then irradiated with UV light having a poly- chromatic output between about 200 to 400 nm to decompose the organic contaminants. The ratio of hydrogen peroxide to transition metal ions is selected so as to favor the absorption of UV light by the hydrogen peroxide in the irradiation step.