Abstract: A method for avoiding the precipitation of salts from a salt containing water stream prior to the stream reaching a supercritical water reactor is presented. The salt containing water stream is preferably kept at temperatures below supercritical conditions as the stream is transferred to the reactor. After the salt stream reaches the reactor the temperature of the salt stream is preferably raised to the appropriate temperature by mixing the salt stream, within the reactor, with a second stream that has been heated above the supercritical temperature of water. Alternatively, a method for preventing the clogging of the conduits upstream from the reactor may involve the mixing of two subcritical waste streams. One stream may include salts, the other preferably includes oxidizable material.

Abstract: A method for treating waste water streams by introducing a mixture of pre-heated waste water and an amount of oxidant lower than that required to oxidize all the organic matter in the waste stream into the front port of an elongate tubular reaction chamber. The amount of oxidant is preferably high enough, however, to raise the temperature of the stream in the reaction chamber to 750.degree.-1,200.degree. F. A first injection side port is preferably located downstream from the front port of the reaction chamber at a distance at which the temperature has reached a maximum value, and 90-100% of the available oxidant has been consumed. Oxidant and water may be simultaneously injected through the first port, in a manner that the amount of oxidant is adequate to oxidize a specified amount of organic matter, and the amount of water is effective to counterbalance the heat produced by the reaction of the co-injected oxidant with the respective organic matter.