A method for oxidizing an organic material includes the steps of (a) forming a preoxidation mixture comprising the organic material and water, and (b) causing the preoxidation mixture to react with a liquid oxidizer in a continuous flow reactor supercritical conditions for water, including a pressure of at least 3206 psia and a temperature of at least 705.degree. F., to form a post-oxidation mixture containing condensible material and non-condensible material, wherein substantially all of the organic material has been oxidized.