Ultraviolet (UV) Water Purifier

Water purification is the method of removing harmful chemicals, microorganisms, and other particulate matter from water. According to the U.S. Environmental Protection Agency, about 90 percent of water is contaminated with pollutants. Hence, purification of water is essential before using it for drinking, medicinal purposes, or industrial purposes.

There are several water purification systems that are effective in removing undesirable substances from the water. Methods of purification can be physical (filtration) or chemical (chlorination). In addition, there are ultraviolet water purifiers that use electromagnetic radiations in order to effectively kill the bacteria, viruses, fungi, algae, and other microbes present in water.

In an ultraviolet water purifier, a UV light source of higher intensity than sunlight--also called germicidal radiation--is used to kill biological contaminants. The spectrum that renders germicidal properties is the short-wave ultraviolet, which is produced by converting electrical energy.

In a UV purifier, a germicidal lamp source with low pressure enclosed in a special quartz glass is used to generate short-wave UV light energy. The lamp is configured in such a manner that passing water is exposed to ultraviolet rays.

The microbes present in the water undergo a change in their nucleic acid (DNA) structure after the exposure to UV rays. Thus, microorganisms are killed by using this kind of water purifier. The effectiveness of killing microbes is directly related to the intensity and time of the germicidal radiation the microbes are exposed to.

For example, a low intensity radiation requires a long exposure of the microbes; whereas, a high intensity radiation is effective to kill biological contaminants even within a short exposure.

A UV purifier offers several advantages over other water purification methods. In fact, it is the most efficient and cost-effective technology available for purification of water. There are no such biological water contaminants that are resistant to UV light.

• It disinfects water without introducing any chemical additives or application of heat.
• It disinfects water within a few minutes, making it much faster than chemical water purification systems.
• It does not alter the chemical composition of water.

• The pH, taste, odor, and other properties of the water remain the same after purification.
• A superior quality ultraviolet water purifier is 99.9 percent effective in removing the harmful microbes.
• Unlike chlorine treatment, a UV purifier is effective against Giardia and Cryptosporidium.

Energy efficient UV purifiers that run on solar energy are available. Easy-to-use and portable purifiers are also available for camping, hiking, traveling, and other recreational activities.

One of the major disadvantages is that a UV purifier is only effective for treating biological water contaminants. Hence, it is necessary to use other water purification systems for physical and chemical treatment of water. The effectiveness of this kind of purifier is lower if the water contains a high amount of suspended particles.

For cloudy water, initial sedimentation or filtration treatment is necessary prior to purification with a UV purifier. The germicidal lamp used in these purifiers should be cleaned and replaced regularly before it burns out. Considering these factors, an ultraviolet water purifier requires high maintenance costs in comparison to other water purification systems.