Inactivation of particle-associated viruses by UV

Ultraviolet (UV) disinfection of bacteriophage MS2 in different waters containing particles was studied and a two-stage survival phenomenon was observed. It was found that turbidity had a negative impact on UV disinfection. In addition, the presence of fecal coliforms (E. coli C) was discovered to have an adverse effect on the virucidal efficiency of UV disinfection. It was also noted that the efficiency of UV disinfection was affected by particle size, number of particles, and particle size distribution. It was assumed that the indicator organisms in the water could be classified into two main categories, namely protected and less-protected to UV irradiation. In the less-protected group, viruses were assumed to exist in a dispersed state. In the protected group, on the other hand, viruses were assumed to exist in a particle-associated state. Based on this assumption, a model was derived for describing the measured inactivation of particle-associated viruses exposed to UV light. The results predicted by the proposed model were in good agreement with the experimental data.