What Contaminants Does UV Remove?

There are no micro-organisms known to be resistant to UV, unlike chlorination. UV is known to be highly effective against bacteria, viruses, algae, molds and yeasts, and disease causing oocysts like cryptosporidium and giardia. In practice, bacteria and viruses are the cause of most major waterborne pathogenic diseases. Of these enteric viruses, hepatitis virus and Legionella pneumophila have been shown to survive for considerable periods in the presence of chlorine, but are readily eliminated by UV treatment. For most microorganisms, the removal efficiency of UV for microbiological contaminants such as bacteria and viruses generally exceeds 99.99%. Specifically, the following are moved to an efficiency of greater than 99.99%: E-coli, Salmonella typhi (Typhoid fever), Salmonella enteritidis (Gastroenteritis), Vibrio cholerae (Cholera), Mycobacterium tuberculosis (Tuberculosis), Legionella pneumophila (Legionnaires' Disease), Influenza Virus, Polio Virus, and Hepatitis A Virus (better than 90%). Countertop UV systems are generally not recommended for removing oocysts such as giardia and cryptosporidium unless equipped with a 0.5 micron carbon block pre-filter since the exposure time the contaminant has to the UV ray is not always long enough to provide an adequate UV dose for disinfection of these more complex organisms. Whole house UV systems like the HC INNEST on the other hand, are capable or killing waterborne oocysts at household flow rates when a properly sized model is selected for the application.

Ultraviolet purification uses a UV light source (lamp) which is enclosed in a protective transparent sleeve (usually quartz). The lamp is mounted such that water passing through a flow chamber is exposed to the UV-C light rays. When harmful microbes are exposed to the UV rays, their nucleic acid absorbs the UV energy, which then scrambles the DNA structure of the organism. The cell is rendered sterile and can no longer reproduce. The cell is now considered dead and is no longer a threat.