Solar photocatalysis for detoxification and disinfection of contaminated water: pilot plant studies

Photocatalytic processes in the presence of titanium dioxide provide an int eresting route to destroy hazardous organic contaminants, being operational in the UV-A domain with a potential use of solar radiation. A preliminary evaluation of a photocatalytic process for water purification has been made to assess its effectiveness in reducing contaminant concentrations of drin king water standards. Studies reported in this paper also evaluate the perf ormance of a low-cost compound parabolic concentrator (CPC) prototype built along this work and explore the feasibility of this concept as the basis f or the solar photocatalytic oxidation facilities of water supplies. From ou r observations, a solar throughput value of 42 l/h m(2) for the low-cost CP C reactor tested at our facilities has been obtained. These calculations ar e based on the time required for the destruction of 500 mu g/l of selected pesticides to maximum permitted levels (0.1 mu g/l) and four-log inactivati on of microorganisms. From the research performed, cost analyses have been made for a full-scale commercial system using the data available in this pr oject. For a 500 m2 facility, the estimated total costs for photocatalytic degradation is competitive with conventional technologies and estimated to be ca. 0.7 $/m(3). (C) 1999 Elsevier Science B.V. All rights reserved.