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 dioxi de (250 mg l(-1)) irradiated with either F40BL fluorescent lights or s unlight. Approximately 150 min were required to achieve two-log inacti vation of coliform bacteria under laboratory lights, while the two-log inactivation of poliovirus 1 occurred in approximately 30 min. No dif ferences in photocatalytic disinfection rates were found when the assa ys were conducted in the pH range of 5-8. The results show that poliov irus 1 was effectively inactivated by titanium dioxide photocatalysis, and the rates were more rapid than for the inactivation of coliform b acteria. However, the photocatalytic disinfection of effluents using t itanium dioxide under sunlight may be limited due to the relatively lo w inactivation rates and resulting long contact times compared to conv entional disinfection methods.