The Effect of Virus-Particle Interactions on UV Disinfection

Most of the existing ultraviolet (UV) dose-response data reported in the literature was obtained from bench-scale UV exposures of pure culture microorganisms in particle-free water. However this may not be representative of the inactivation of particle-associated microorganisms that may be encountered during water and wastewater treatment. Particle-association may protect pathogens from disinfection and result in lower microbial inactivation than would be predicted from established dose-response relationships. This study investigated the influence of virus-particle association on UV disinfection. Specifically, the objectives of the study were to determine whether colloidal particles could protect viruses from UV light and to determine which particle characteristics (i.e. size, organic content) enhance protection. It was shown that colloidal particles are able to protect viruses from UV disinfection and that particulate organic content enhances survival of particle-associated viruses.