TiO₂-Mediated Photochemical Disinfection of Escherichia coli Using Optical Fibers

We have constructed a system for photochemical disinfection of bacteria using a suspension of titanium dioxide and diffuse-light emitting optical fibers (DLEOFs). Disinfection of bacteria at high Ti02 concentrations was light-limited when conventional optical fibers were used to supply light to the cell suspension. However, when using DLEOFs that emit light laterally from their surface, light distribution throughout a suspension of Escherichia coliwas greatly improved even in the presence of high TiO₂ concentrations. A 4-fold increase in photochemical disinfection was obtained at high TiO₂ concentrations using DLEOFs rather than conventional optical fibers for light supply. The use of DLEOFs should provide a generally applicable method for photodisinfection of water supplies.