High-performance, low-cost solar collectors for disinfection of contaminated water

Although the germicidal action of sunlight has long been recognized, its po tential for practical applications has to be researched more thoroughly. Th is paper summarizes the progress made toward a commercially practical colle ctor for solar disinfection applications. Nontracking compound parabolic co llectors (CPCs), developed originally for capturing solar photons for therm al energy applications, were examined as potential solar photoreactors. A f ield demonstration of solar disinfection treatment using commercially manuf actured solar reactors was conducted. Field tests showed successful destruc tion of Escherichia coti and Enterococcus faecalis and have provided data f or full-scale design of water treatment systems. From above observations, a throughput value of 50 L/m(2).h for the low-cost CPC reactor tested was es timated. For a 190 m(2)/d (0.05 MGD) facility. the estimated total costs fo r disinfection using UV-A is U.S. $0.19/m(3) ($0.70/1000 gal). The use of n ear-UV sunlight to disinfect water supplies seems promising in rural commun ities of developing countries where treated water is unavailable.