Know about the functions of the ultraviolet water filtration

Know about the functions of the ultraviolet water filtration

Ultraviolet water filtration is the process that offers one of the most cost-effective ways to purify water, thereby protecting drinking water against biological contaminants. Ultraviolet or UV protect against water-borne viruses, bacteria, molds, and other pathogenic diseases. Viruses such as hepatitis virus that is known to be highly resistant to chlorine treatment can be relatively eliminated through UV treatment.

Let us have a look at how UV water filtration works

  • Invisible Ultraviolet light is emitted from a UV light source that has an output of roughly 254 nanometers, producing radiation that has a significantly greater density than the radiation in the sunlight.
  • The flow chamber contains the light source through which water passes. This exposes the water to the UV light. The light source used in such water filtration system is usually a mercury vapor lamp, also called as the germicidal lamp.
  • An electric arc present in the filtration system vaporizes the mercury present in the lamp. The mercury present inside the lamp vaporizes, thus producing UV rays of short wavelength.
  • These lamps are made out of special quartz glass that permits short UV rays of around 2530 A (Armstrong unit). The wavelength of such short magnitude is achieved due to the low pressure inside the lamp.
  • Before purifying the water through UV filtration system, the water is passed through a separate filter to remove any turbidity present in the water. This is because clear water allows better penetration of UV light. Most water filtration systems use a filter of 5-micron before passing it through the mercury vapor lamp.

Pros and cons of using UV water filtration systems

  • The primary advantage of using a UV filtration system is that it is cost-effective and kills a majority of harmful microbes that cause water-borne illnesses.
  • These water filtration system starts at just about $250 if you intend to use it as a localized filtration system. Whole house water filtration system costs around $1500.
  • UV water filtration system doesn’t consume much electricity and requires as low as 100 watts of power to function.
  • Easy to install and maintain, these water purifiers do not damage the septic tanks or plumbing of the household.


  • Even if these water purifiers consume less power, they still require some amount of electricity. Hence these water purifiers cannot work in the event of power outage.
  • UV rays cannot be seen by the naked eye because of their short wavelength, hence it is hard to determine if the UV apparatus in the purifier is still working. Thus, it becomes necessary to change the filters twice every year.