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: A wet oxidation process is used to control the concentration of reduced sulfur compounds from a viscose process. The wet oxidation process oxidizes the reduced sulfur compounds to convert such reduced sulfur compounds to an alkali sulfate and/or thiosulfate species. The alkali sulfate stream is recycled to the viscose process. Oxidation is performed under elevated temperature and pressure conditions such that the offgas has an oxygen concentration of between about 2% to 18% and the alkali sulfate stream has a pH of about 2 to 10.