How does an Uv Ir-radiator function in the context of water treatment?

In the context of water treatment, a UV-irradiator functions primarily by using ultraviolet light to inactivate or kill microorganisms such as bacteria, viruses, and protozoa. The process involves the absorption of UV light by the DNA or RNA of these pathogens, which causes damage that prevents them from replicating. This mechanism is effective because once the genetic material is altered, the microorganisms can no longer function or reproduce, thereby rendering them harmless.

This method of disinfection is advantageous as it does not introduce any chemicals into the water, making it an environmentally friendly option. Additionally, UV treatment does not affect the taste or odor of the water, and it can be used effectively in a variety of water sources.

In contrast, other methods mentioned in the options do not apply to how a UV-irradiator works. For instance, filtering out impurities through membranes refers to physical filtration processes like reverse osmosis; adding chemicals involves chemical disinfection methods such as chlorine or ozone; and cooling the water might reduce the growth rates of some pathogens but does not directly eliminate them in the manner that UV irradiation does.