Photocatalytic disinfection of E coli in a UV/TiO2-immobilised optical-fibre reactor

Photocatalytic disinfection using TiO2 particles suspended in a reactor inv olves two major problems; the exponential decrease of light availability du e to the scattering of UV light by particles themselves and the difficulty of recycling particles. To resolve these problems, scratched optical-fibres , inserted in glass tubes were used to diffuse UV Light uniformly in a reac tor. Comparative disinfection studies using these optical-fibres were done in both cases of suspended and immobilised photocatalysts. Disinfection cap ability with the immobilised photocatalysts at 4.9 muE s(-1) dm(-3) was twi ce that of the slurry reactor. Survival ratios of less than 0.2 were obtain ed with a residence time of 50 min and an initial cell concentration of 100 00 cfu cm(-3) in the 6 dm(3) plug-flow type reactor. (C) 2000 Society of Ch emical Industry.