Final answer:
Bromate is a toxic disinfection byproduct sometimes formed when natural waters containing bromide ions are treated with ozone disinfection. Ozone acts as a powerful oxidizing agent, but does not leave a residual disinfectant, leading to potential bromate formation.
Step-by-step explanation:
When natural waters are subjected to ozone disinfection, a disinfection byproduct called bromate is sometimes formed. Ozone disinfection, also known as ozonation, is a process where ozone, an unstable molecule that readily gives up one atom of oxygen, acts as a powerful oxidizing agent. This method is toxic to most waterborne organisms and is effective against a wide range of pathogens, including protozoa that form cysts.
Ozone is generated on-site by passing oxygen through ultraviolet light or via a 'cold' electrical discharge, and it is added to water through bubble contact. While offering advantages such as fewer dangerous by-products and no taste or odor issues compared to chlorine, it does not leave a residual disinfectant in the water. Thus, sometimes chlorine or chloramine is added to the distribution system to ensure the inactivation of any potential pathogens.
However, when natural waters with bromide ions undergo ozonation, there is a risk of bromate formation, a toxic compound. The issue of bromate formation is of particular concern because of its potential health risks.