Photocatalytic enhancement of solar water disinfection for application in developing regions

Solar water disinfection (SODIS) is an effective, simple, household level, point-of-use technology suitable for application in developing countries. Contaminated water is placed in a plastic container (typically a 2L PET bottle) and exposed to sunlight for at least 6 hours. Laboratory and field trials have demonstrated SODIS to effective against a wide range of waterborne pathogens with health impact assessments demonstrating significant benefits from consumption of SODIS treated water. Photocatalytic (PC) enhancement of the SODIS process could provide larger volumes of safe drinking water and reduce the sunlight exposure time.Pilot scale, modular PC-SODIS reactors were designed and constructed from low-cost materials and tested, under real sunlight the south of Spain, for their efficiency to disinfect water containing ~1 x106 Escherichia coil cells/mL. The inclusion of an immobilised nanostructured titanium dioxide coating within 1.25 L static batch and 7 L re-circulating reactors accelerated the rate of disinfection with 6-log kill observed in 3 hours. Complete disinfection was not observed in re-circulating SODIS reactors. Photocatalytic enhancement was observed during full sun and cloudy weather conditions.