Decomposition of organic substances in water by combined O/sub 3//TiO/sub 2//UV process for the reuse of wastewater

A combined process using ozone and titanium dioxide under the illumination of UV light (O/sub 3/TiO/sub 2//UV) was tested to decompose refractory organic substances in wastewater. A synergistic effect was observed between ozone and illuminated TiO/sub 3/, and more than 60 percent of total organic carbon (TOC) in wastewater was removed by the O/sub 3//TiO/sub 2//UV process. The quantum yield for the reaction in the O/sub 3//TiO/sub 2//UV process was obtained, and trial calculations were made of the energy and cost required for the decomposition of organic substances. If a black-light lamp is used as the light source, trial calculations based on the results show that TOC can be removed at the rate of 1 mg/L at an electric energy of 0.59 kW/spl middot/hr/m/sup 3/, which indicates that a low-cost circulation system can be created with the use of the O/sub 3//TiO/sub 2//UV process.