UV-TiO2 photocatalytic disinfection and photoreactivation of pathogenic bacterium in municipal wastewater

摘要

The disinfected bacteria will be a photoreactivation under the irradiation of the sunlight, and the light intensity plays an important role in the bacteria resurrection. The effect of light intensity on photoreactivation ofEscherichia coli(E. coli) and Enterococcus faecalis(E. faecalis) in secondary effluents which were disinfected respectively by pure UV and UV-TiO2was investigated. The results show that the disinfection efficiency of UV-TiO2 is much higher than that of the pure UV disinfection. The photoreactivation rate ofE. coli is much higher in pure UV disinfection than in UV-TiO2 photocatalytic disinfection. Under high light intensity in UV-TiO2 disinfection, high resurrection rate can be induced. However, a higher resurrection rate can be introduced even under low light intensity in pure UV disinfection alone. Meanwhile, UV-TiO2 disinfection has a strong inhibition effect on E. faecalisphotoreactivation. When the light intensity is lower than 21μW/cm2, nearly no resurrection ofE. faecalis occurs after 72 h resurrection irradiation, and a little resurrection rate is observed only under a strong photoreactivating light intensity.