Solar disinfection of poliovirus and Acanthamoeba polyphaga cysts in water – a laboratory study using simulated sunlight

Aims:  To determine the efficacy of solar disinfection (SODIS) in disinfecting water contaminated with poliovirus and Acanthamoeba polyphaga cysts. Methods and Results:  Organisms were subjected to a simulated global solar irradiance of 850 Wm−2 in water temperatures between 25 and 55°C. SODIS at 25°C totally inactivated poliovirus after 6-h exposure (reduction of 4·4 log units). No SODIS-induced reduction in A. polyphaga cyst viability was observed for sample temperatures below 45°C. Total cyst inactivation was only observed after 6-h SODIS exposure at 50°C (3·6 log unit reduction) and after 4 h at 55°C (3·3 log unit reduction). Conclusions:  SODIS is an effective means of disinfecting water contaminated with poliovirus and A. polyphaga cysts, provided water temperatures of 50–55°C are attained in the latter case. Significance and Impact of the Study:  This research presents the first SODIS inactivation curve for poliovirus and provides further evidence that batch SODIS provides effective protection against waterborne protozoan cysts.