Fabrication of pilot-scale photocatalytic disinfection device by installing TiO2 coated helical support into UV annular reactor for strengthening sterilization

Abstract

Herein, a continuous-flow-mode photocatalytic disinfection device with the capacity of 1m3/h was presented. The core reactor of the photocatalytic device was structured by installing a TiO2 (Degussa P25) coated helical support around a UV lamp into an annular reactor. This photocatalytic device exhibited superior disinfection capability to UV technology. After 2.42×106CFU/L of Escherichia coli (E. coli) suspension flowed through the photocatalytic device, 3.05log10 reduction of E. coli was removed, while only 2.57log10 reduction of E. coli was removed by UV disinfection device. The residual E. coli in the effluent decreased to only 2.16×103CFU/L for photocatalytic device, which was distinctly lower than 6.44×103CFU/L for UV disinfection process. Photocatalytic disinfection also displayed prominent ability in restraining E. coli reactivation. After 24h of preservation, concentration of E. coli in effluent for UV process was found as 1.20×104CFU/L (0.74log10 of increase), 16 times less than 1.99×105CFU/L (1.49log10 of increase) of UV process. Moreover, the photocatalytic device exhibited high endurance to flux fluctuation and E. coli concentration change. These results demonstrated an access of applying photocatalytic technology to applying for disinfection of wastewater.