Solar detoxification of hazardous waste : an overview of the U.S. Department of Energy program

Abstract To move the application of solar concentrating systems into the marketplace, the U.S. Department of Energy's (DOE) Office of Assistant Secretary for Conservation and Renewable Energy recently began a Solar Industrial Program. The primary emphasis within this program is to accelerate the development and testing of the solar detoxification systems for hazardous wastes and to reach commercial applications in the mid-1990s. Leading the implementation of this program, the Solar Energy Research Institute in Golden, Colorado, is working in conjunction with Sandia National Laboratories in Albuquerque, New Mexico. The program includes development of technology for solar detoxification of hazardous waste and advanced industrial applications. The solar detoxification investigations are in two different processes for destroying toxic wastes: solar detoxification of water at near ambient temperature using low solar concentration, and solar destruction of chemical wastes using high temperature and higher solar concentration. In the first area, a typical photocatalytic process is used, where water containing organic wastes is exposed to sunlight in the presence of a semiconductor catalyst such as titanium dioxide. Wastes are destroyed in a single step without first removing them from the water and the entire operation takes place on site. The second process is a high-temperature, high-flux process for destroying hazardous and toxic compounds which is a promising alternative to thermal treatments such as incineration. For solar detoxification technologies to have an impact on this timeframe they must move quickly from the laboratory to actual waste sites. The program is designed to propel these technologies from the laboratory to field experiments and into the hands of industry within the next five to seven years.