Repression of photoreactivation and dark repair of coliform bacteria by TiO2-modified UV-C disinfection

摘要: Abstract Photoreactivation and dark repair of damaged DNA can occur after some bacteria are disinfected with UV-C irradiation thus reduce the disinfection efficiency. We have discovered that provision 1 mg/L titanium dioxide (TiO 2 ) in suspension during at normal doses repressed photoreactivation repair. The repressive effect was also observed when a TiO -coated plate used exposure but removed thereafter, indicating does not require presence post-UV event. consistently changes species, temperature, salinities, UV sources, intensities, with/without nutrients. is likely associated additional radical attack UV-TiO and/or formation small amount stable residual oxidants (primarily hydrogen peroxide). -modified represents an innovative means to disinfect water. It particularly useful situations where additions chlorine or chloramines allowed possible. Nevertheless, shall be properly included, by either using optimum dose immobilizing it onto surface, since too little cannot provide repression while much gives detrimental on disinfection.