Abstract: A system and method for the treatment of process streams is provided. A catalyst mediates a wet oxidation process at elevated temperatures and pressures for treating at least one undesirable constituent in an aqueous mixture. A catalyst may be selected for its solubility at a detected pH level of the aqueous mixture. Alternatively, a pH level of the aqueous mixture may be adjusted to solubilize a selected catalyst and/or maintain the selected catalyst in a soluble form. A controller in communication with a pH sensor may be configured to generate a control signal to adjust the pH level of the aqueous mixture in response to the pH sensor registering a pH level outside a predetermined pH solubility range for a selected catalyst.

Abstract: Systems and methods for process stream treatment. The treatment system may generally include an oxidation unit coupled to a downstream demineralization unit. The oxidation unit may oxidize organic and reduced sulfur contaminants in the process stream to facilitate downstream treatment. The demineralization unit may convert a product of the oxidation unit to generate a mineral stream. In some examples, the process stream may be a spent caustic stream from an industrial operation, such as an ethylene production facility or a petroleum refinery. A fresh caustic stream, such as a sodium hydroxide stream, may be isolated in the demineralization step and returned to the industrial operation for use.

Abstract: A system and method for the treating at least one undesirable constituent in an aqueous mixture utilizing a particulate solids catalyst. The aqueous mixture and the particulate solids catalyst form a slurry which is wet oxidized.