Ultraviolet (UV) is a kind of disinfectant, it can kill bacteria and viruses, including microbial, although some microorganisms than other microorganisms on UV bear ability better. This process does not use chemical agent, but to allow water in the inner container subjected to high intensity of UV irradiation. Ultraviolet light can at the cell level to destroy microbes: kill them, or make them lose the ability to replicate. No replication-competent virus is harmless.