Ultraviolet water purification/ sanitisation lamps generates UV-C or “germicidal UV” radiation which is of a much greater intensity/ concentration than usual sunlight UV. Virtually all of the UV lamp’s output is concentrated in a 254 Nano-meters (nm) area – so as to take full advantage of the germicidal properties of this unique wavelength. The majority of UV purification systems are combined with several forms of filtration – since UV radiation is only proficient in killing microbes like viruses, bacteria, moulds, algae, yeast, and oocysts like giardia and cryptosporidium.
UV radiation typically has no impact on chlorine, Volatile Organic Compounds (VOC’s), heavy metals, and other chemical impurities. Nonetheless – it is perhaps the most affordable and effective technology available to homeowners to eradicate a wide array of biological pollutants from their drinking water. Recent analysis has also shown that UV can be effective at terminating certain VOC’s – though I would not recommend the technology for complete VOC reduction.
Ultra-Violet water purification offers various advantages over other types of water treatment in terms of microbiological contaminants. First and foremost, it doesn’t add any chemicals to the water, it yields no by-products, and it does not alter the pH, taste, or any other properties of the water. In addition to producing healthy drinking water, it is not damaging to your plumbing and septic systems. Furthermore, it is very simple and cost-effective to install and maintain without any specialist training.
How it works: Ultra-Violet water purification employs a UV light source (lamp bulb) which is enclosed in a protective transparent sleeve (typically quartz-crystal). The lamp is mounted in such a way that the water passing through a flow chamber is exposed to the UV-C rays. Once the microbes are exposed to the UV rays, their nucleic acid absorbs the UV radiation – which in turn destroys the DNA structure of the micro-organism. Consequently – The cell is rendered sterile and can no longer reproduce, and is now considered dead and harmless.
Purpose: Ultra-Violet radiation treatment is a fantastic choice for eradicating biological contamination from most drinking water – whether your house is on a municipal water system or unprocessed private system (well, lake water, spring). Its sole purpose is to destroy dangerous biological impurities, and should always be combined with other methods of filtration (reverse osmosis, GAC /carbon block or KDF) for reduction of VOC’s, chlorine, heavy metals, and other chemical impurities.
What impurities does UV treatment remove: At present, there are no microbes known to be resistant to Ultra-Violet radiation, dissimilar from chlorine. UV is known to be highly efficient against viruses, bacteria, moulds, algae, and disease producing oocysts like giardia and cryptosporidium. In reality, viruses and bacteria are the chief cause of most waterborne pathogenic ailments. Of these enteric viruses, hepatitis and Legionella pneumophila have been revealed to survive for substantial periods in the presence of chlorine, but are effortlessly destroyed by UV radiation. The removal effectiveness of UV for microbiological contaminants such as viruses and bacteria usually exceeds 99.99%. The following are believed to have an efficiency of greater than 99.99%: E-coli, Typhoid fever, Gastroenteritis, Cholera, Tuberculosis, Legionnaires ‘ disease, Polio Virus and Influenza virus.
Countertop UV water purification systems are generally not recommended for removing oocysts, unless fitted with a 0.5 micron carbon block pre-filter, because the exposure time the contaminant receive is not always adequate to provide an sufficient UV dose for decontamination of these more complex microbes. Whole house UV purification systems on the other hand, are capable or killing waterborne oocysts if a properly sized model is selected for the application.