PHOTOCATALYTIC INACTIVATION OF COLIFORM BACTERIA AND VIRUSES IN SECONDARY WASTE-WATER EFFLUENT

The inactivation of coliform bacteria and poliovirus 1 was studied in secondary wastewater effluent containing suspensions of titanium dioxide (250 mg l(-1)) irradiated with either F40BL fluorescent lights or sunlight. Approximately 150 min were required to achieve two-log inactivation of coliform bacteria under laboratory lights, while the two-log inactivation of poliovirus 1 occurred in approximately 30 min. No differences in photocatalytic disinfection rates were found when the assays were conducted in the pH range of 5-8. The results show that poliovirus 1 was effectively inactivated by titanium dioxide photocatalysis, and the rates were more rapid than for the inactivation of coliform bacteria. However, the photocatalytic disinfection of effluents using titanium dioxide under sunlight may be limited due to the relatively low inactivation rates and resulting long contact times compared to conventional disinfection methods.