UV water purification is a method of water filtration which uses ultra-violet light to kill all germs, bacteria, microbes, cysts, etc. in water. Ultraviolet water purification is a simple but effective process that destroys around 99.99% of the harmful organisms in water.
There is a mercury vapor lamp, also called germicidal lamp inside the UV water purifiers. This lamp is connected to an electric arc that produces heat to vaporize the small amount of mercury inside the lamp. The vaporized mercury becomes ionized which in turn gives off short wave ultra violet radiations. These UV radiations irradiate the water and penetrate the cells of bacteria and viruses, destroying their ability to reproduce. These organisms fail to multiply and eventually die. This purification method only kills the germs but the bodies of the dead germs remain in the water. Separate filters are required to remove the germs physically. UV water purification is usually done in conjunction with other forms of filtration such as reverse osmosis or activated carbon filters.
Pros of UV water purifiers
- A normal UV purifier requires very less energy for operation, approximately the same amount of energy as a 60 watt bulb
- UV rays do not damage septic tank or plumbing systems
- UV filters do not introduce chemicals or bi-products in water due to which the taste and odor of water remains unaltered
- UV purifiers are easy to maintain as the mercury lamp is replaced only once a year
- They are affordable and easy to install
Cons of UV water purifiers
UV purifiers work well when the water is clear. They are not very effective when the water is muddy and contains sediments. Also UV rays only kill the germs but the bodies of the dead germs remain suspended in water. Therefore separate filters are required to remove the germs and sediments physically.
UV method works best when used with RO purifiers. UV rays kill the harmful microbes and RO process filters them out. Also the dissolved salts and suspended particles which the UV purifiers cannot remove are taken care by the RO filters and membrane.