Supercritical Water Oxidation for Wastewater Treatment: Preliminary Study of Urea Destruction

Supercritical water oxidation is being investigated as a method of treating spacecraft wastewater for recycle. In this process, oxidation is conducted in an aqueous phase maintained above the critical temperature (374°C) and pressure (215 bar) of water. Organic materials are oxidized with efficiencies greater than 99.99% in residence times of less than 1 minute. This paper presents preliminary results for urea destruction. Above 650°C, urea can be completely broken down to nitrogen gas, carbon dioxide and water by supercritical water oxidation, without the use of a specific catalyst.