Abstract : Pilot plant of an integrated water processing system has been developed. The Water Processing System treats nonsanitary wastewaters of the U.S. Army field hospitals either for nonpotable reuse or for surface discharge to the environment and purifies natural fresh and brackish waters for potable use. The Water Processing System Consists of four units: (1) a Water Treatment Unit, (2) a Water Purification Unit, (3) a UV/Ozone Oxidation (O3/UV) Unit and (4) an Automatic Instrumentation Unit. This report describes the development of the O3/UV Unit. Emphasis has been placed on the UV/ozone oxidation technology developed for the design of the O3/UV unit.