Ultraviolet water purification is considered as the most effective and environmentally friendly option to destroy microbes from municipal as well as rain, stream, spring, bore or lake water supplies. Ultraviolet rays are invisible and emitted by different light sources including the sun. UV rays penetrate the disease-causing organisms and destroy its DNA, rendering it incapable of reproducing.
An ultraviolet water purifier or disinfection systems employ a UV light source with an output of around 254nm, radiation of significantly greater intensity than that produced by sunlight. The UV light source and the filter that protects the lamp are mounted within a flow chamber through which the water passes.
Advantages of UV water purification:
- Effective against a wide range of microorganisms, and can eliminate 99.9% of bacteria, viruses, and chlorine resistant microbes like giardia and cryptosporidium. These pathogens are the cause of water-borne diseases like typhoid, gastroenteritis, Cholera, Flu, and Hepatitis. This is one of the four methods of water disinfection approved by the FDA.
- UV systems do not use any chemicals hence no by-products, as in the case of chlorine disinfection of water. It is an environment-friendly and safe method as no handling of dangerous chemicals are involved. There is no change in the color and taste of the water after treatment. Besides, UV radiation filters do not produce any harmful bi-products.
- It is cost-effective as it has low running costs and uses compact units, which are easy to maintain. A UV disinfection system works efficiently with little or no intervention. It is a fast and reliable method with low energy use. UV lamps need replacement yearly;there is no other equipment required like a holding tank or reaction time.
However, UV disinfection alone may not be effective in case of turbid water as the suspended organic and inorganic matter may absorb the UV light, shielding microbes.The percentage of organisms destroyed will depend on the intensity of UV light, contact time and efficiency of the unit. Moreover, UV light is ineffective in removing chlorine, heavy metals, and salts. Finally, UV water treatment systems require electricity. When used in conjunction with filtration, it can prove to be an excellent method to ensure healthy and clean drinking water.