Disinfection of drinking water using photocatalytic technique

High surface-area TiO2 photocatalysts; supported on a glass tube and a stainless steel plate were prepared and evaluated for their bactericidal effect using water primed with Escherichia coli, in a quartz reactor using 350 nm light and solar light. E. coli concentration decreased to a safe level from initial concentration of 500-100,000 bacteria/ml during 4 h of photolysis using 350 nm light and solar light. Time required for disinfection of water was found to increase with increase in the concentration of bacteria. Dissolved inorganic impurity (1 wt% NaCl) did not have any adverse effect on bactericidal activity. However, small amount of dissolved organic impurity (10 ppm nutrient agar) decreased bactericidal activity by similar to 40%. The technique was found to be effective when 1 l of water was photolysed by solar light in a plastic tray containing TiO2 photocatalyst coated on a stainless plate. Our study indicates that the technique can be used for disinfection of similar to 20 l water daily using solar light. Based on the photocatalytic technique using solar light, a viable, simple and easy-to-use device for disinfection of drinking water on litre scale is reported.