UV effectively inactivates microorganisms
Disinfection with UV is a fast process that effectively inactivates microorganisms. When virus, bacteria and protozoa are exposed to UV, the DNA of the cells get altered so they will not be able to reproduce anymore and they will hence be harmless. The highest amount of energy from UV are emitted at wavelength 254nm and it is found in the electromagnetic spectrum between the spectrum of x-rays and visible light. For the UV light to kill microorganisms, the cell of the organism must be exposed to the rays. The energy in the UV light will penetrate the outer cell membrane, will pass through the cell body and then hit and alter the cell DNA. Treatment with UV will hence not change the water chemically since nothing is added except energy. The microorganisms that are killed will hence not be removed from the water. Disinfection with UV will not remove dissolved organics, inorganics or any particles in the water.