Laboratory tests were conducted to determine the feasibility of electro-oxidation as a means of removal of ammonia from wastewaters. It was determined that, under conditions of ammonia concentration and pH typical of treatment effluents, the electro-oxidation reaction proceeded stoichiometrically to nitrogen and no other oxidation products. Oxidation occurred in concentrations as low as 2 mg/l of ammonia. Using platinized platinum as an electrode, ammonia decomposition occurred in a narrow potential rnage with high coulombic efficiency, assuming a three-electron exchange per ammonia molecule. Conversion of nitrogen to the elemental form was demonstrated by analysis of the gas from the anode. No detectable quantities of nitrite, nitrate hydrazine, and hydroxylamine were discovered in the gas. Electric power costs were estimated at $.01/1000 gallons, but cost of the platinum electrodes was prohibitive. Experiments with other electrodes were unsuccessful. Unless less expensive electrodes are developed, the process cannot be economically competetive with other methods.

"17010EED07/70." Prepared under contract no. 14-12-800. Includes bibliographical references. Microfiche.