Solar detoxification

T0544 National Renewable Energy Laboratory, Solar Detoxification of Water... 

Titanium dioxide, which is known to be effective in solar detoxification, only adsorbs about 3% of solar radiation and has a low yield of hydroxyl radicals. Solaqua has been demonstrated to be at least 25 times more effective for the destruction of organic molecules than sunlight/titanium dioxide. 

Researchers claim the following advantages of solar detoxification ... 

Halide-saturated hydrocarbons such as carbon tetrachloride degrade very slowly, if at all, when exposed to solar detoxification treatment. Bicarbonate, a common constituent of groundwater, acts as a scavenger of hydroxyl radicals and can significantly hinder solar detoxification treatment. The presence of nontargeted contaminants in process infiuent can lower process efficiency. 

A cost analysis was performed in 1991 for a solar detoxification system at Livermore, California, capable of processing an average of 4.4 liters/sec of water with a peak flow of 30 liters/sec. The system would be processing water containing 400 parts per billion (ppb) trichloroethylene to a treated concentration of 5 ppb. Costs were estimated at 16.00 per 1000 gal. Data from the field test using a one-sun mode of operation reduced the estimated cost to roughly 7.00/gal (D12953N, p. 203). 

A similar estimate at the Radian Corporation estimated costs at 15.40 per 1000 gal. This estimate was higher than for alternative technologies ultraviolet oxidation ( 4.00 per 1000 gal) and granular activated carbon treatment ( 5.00 per 1000 gal). It was predicted, however, that costs of solar detoxification could be lowered to 3.00 per 1000 gal. The Radian study noted that costs at the Livermore site may be higher than for most applications of solar detoxification technology. It estimated the cost of conventional treatment would range from 1.40 to 3.00 per 1000 gal (D12953N, pp. 203). 

Sensitivity studies have shown that costs are likely to be contaminant specific and depend on plant size and location. The design of a commercial facility has not been finalized. Solar collectors are the largest cost component of solar detoxification systems, and some research indicates that a one-sun system (in a one-sun system, solar energy is not concentrated by reflectors or solar panels) that does not use a solar collector may be more efficient in accessing diffuse ultraviolet light. Another design concern that may impact process costs is the use of a fixed catalyst versus a slurry feed (D12953N, pp.190-203). 

Blanco J, et al. Compound parabolic concentrator technology development to commercial solar detoxification applications. Sol Energy 1999 67 317-330. 

Prairie M. R., Pacheco J. and Evans L. R. Solar Detoxification of Water Containing Chlorinated solvents and Heavy Metals via Ti02 Photocatalysis, Prepared for the 1992 ASME Inti. Solar Energy Conf., April, SAND91-1285C, Sandia National Laboratory, Albuquerque, NM (1992). 

Xi W, Geissen S-U, Vogelpohl A (2000) Solar Detoxification of Wastewater in a Novel Aerated Cascade Photoreactor (AGP), Proceedings of the 2 International Conference on Oxidation Technologies for Water and Wastewater Treatment, Clausthal-Zellerfeld, Germany, 28-31 May 2000, Wat. 

Platband potential Haloge-Solar detoxification Titanium... 

Jorgensen, G. and Rangaprasad, G., Ultraviolet Reflector Materials for Solar Detoxification of Hazardous Waste, SERI/TP-257-4418, SERI, Golden, CO, 1991. 

Bockelmami, D., Goslich, R., Weichgreb, D.,aiid Bahiiemaiiii, D., 1993, Solar detoxification of polluted water Comparing the efficiencies of a parabolic reactor and a novel thin-film fixed-bed reactor, in Photocatalytic purification and treatment of water, Ollis, D., and Al-Ekabi, H., eds., Elsevier, New York, pp. 639-644. 

Crittenden, J. C., Zhang, Y., Hand, D. W., 1996, Solar detoxification of fuel-contaminated groundwater using fixed-bed photocatalysts. Wat. Environ. Res. 68(3) 270-278. 

Muradov, N. Z., 1994, Solar detoxification of nitroglycerine-contaminated water using immobilized titariia. Solar Energy, 52 283-288. 

Blanco, J. Malato, S. Solar Detoxification. World Solar Progr. 1996-2005 Natural Sciences UNESCO, 2001. (http /Avww.un co.org/science/wsp)... 

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