A method of treating organic waste is provided which includes separating the liquid portion of the waste from the solid portion prior to reacting said solid portion in an accelerated wet oxidation reaction. The method includes using an internally-derived ash from the wet oxidation reaction to weight the organic waste, thereby increasing the rate at which the liquid phase can be separated from the solid phase. By first removing the liquid portion of the waste, the oxygen demand of the waste to be processed by wet oxidation is substantially lowered. Ammonia is removed from the liquid portion of the waste in a de-ammoniating step which is followed by biological decomposition to form a liquid stream having a greatly reduced oxygen demand. In one embodiment, the method includes further treating the liquid stream to substantially remove salts and using the resulting deionized stream as a diluent to dilute the solid portion of the waste prior to wet oxidation. The present invention also provides a method of treating organic waste which includes reacting said waste in accelerated wet oxidation reaction apparatus to produce a low-volume sterile ash, a liquid effluent portion and a mixture of reaction off gases. The liquid effluent portion is de-ammoniated then decomposed biologically to form a liquid stream having a greatly reduced oxygen demand. The liquid stream is then desalinated and used as a diluent to dilute the organic waste prior to its introduction into the wet oxidation reaction apparatus.