the process of this invention destroys contaminants in a contaminant - containing aqueous stream . the subject process comprises providing a contaminant - containing aqueous feed stream including an initial amount of at least one of a group of contaminants including perchlorates , nitrates , and nitrites . the contaminant - containing aqueous feed stream includes a reducing agent . next the reducing agent - containing , contaminant - containing aqueous stream is heated . finally , the heated contaminant - containing aqueous stream is contacted with an oxidation - reduction catalyst for a period of time sufficient for reducing the excess amount of any of the perchlorates , nitrates , and nitrites contaminants by at least about 90 %.