Ultra Violet Sterilization
Ultraviolet disinfection of water consists of a purely physical, chemical-free process. UV-C radiation in particular, with a wavelength in the 240nm to 280 nanometers range, attacks the vital DNA of the bacteria and viruses directly. When ultraviolet energy is absorbed by the reproductive mechanisms of bacteria and viruses, the radiation initiates a photochemical reaction that destroys the genetic information contained in the DNA. The bacteria and viruses 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, like distillation, disinfects water without adding chemicals, and therefore possesses some of the same benefits as distillation. It does not create new chemical complexes, nor does it change the taste or odor of the water, and does not remove any beneficial minerals in the water.
In circumstances, mostly with the very young, the elderly, or immune compromised individuals such as those on chemotherapy; where there is special concern for not having any chance of water born microbes in the drinking water, UV sanitation would be a consideration. City water is generally very sanitary to begin with, but sometimes this extra measure is necessary or prudent. Well water would also be a very good candidate for UV sanitation in the filter stream.
This UV stage may be used as the last stage on POU filter systems for well water in rural areas, or in towns and villages that have uncertain chlorination. A UV stage is available as a sub-assembly which can be added to an existing filter system.
Ultra Violet Lights Claim to Fame
- Ultraviolet light kills 99.9% of harmful bacteria in point-of-use filter systems and water coolers.
- Ultraviolet light is FDA approved for disinfecting filtered water.
- Adding a UV stage will reduce the need for cleaning and flushing filter systems.
How Ultra Violet Light Works: In Practice
The UV lamp stays on continuously. As the water flows around the lamp, it is irradiated by the ultraviolet light. Water flow is restricted to .5 GPM to allow time for the UV light to be effective. The lamp slides into a quartz tube which is sealed from the water and a purple color shows through the plastic flow fittings while it is working. An alarm in the power-pack sounds when the bulb burns out.
The easily replaceable bulb is housed in a stainless steel tube and has a 9000 hour life (over a year). Replacement lamps are available separately
Ultraviolet devices are most effective when the water has already been partially treated, and only the cleanest water passes through the UV flow chamber.
Ultraviolet light is a natural, cost effective, environmentally friendly disinfection process for use in homes where healthy water is a concern.