The disinfection process
Ultraviolet disinfection of water consists of a purely physical, chemical-free process. The bacteria in water that passes through UV light lose their reproductive capability and are destroyed. Even parasites such as Cryptosporidia or Giardia, which are extremely resistant to chemical disinfectants, are efficiently reduced. UV can also be used to remove chlorine and chlormaine species from water. UV disinfection does not remove dissolved organics, inorganic compounds or particles in the water.
UV water treatment devices can be used for well water and surface water disinfection. UV treatment compares favorably with other water disinfection systems in terms of cost, labor, while being perhaps the simplest to operate. Chlorine disinfection treats larger organisms and offers residual disinfection, but these systems are expensive and produce a steady supply of a potentially hazardous material. Finally, boiling water over a cook stove is the most reliable treatment method but it is not practical. UV treatment is rapid and, in terms of primary energy use, approximately 20,000 times more efficient than boiling.