UV light is electromagnetic radiation with wavelengths shorter than visible light. UV can be separated into various ranges, with short-wavelength UV (UVC) considered “germicidal UV” that is used for drinking water sanitation, among other things. At certain wavelengths, UV is mutagenic to bacteria, viruses and other microorganisms.
As you can’t see, smell, or taste microbes in water, a water test is all the more critical. But with microbiological contaminants, the water test is simply a snapshot in time. With hard or iron-containing waters, the level of these minerals is less likely to change over time. Microbiological contamination, however, can change unexpectedly. A sudden thaw, a torrential downpour, a septic tank that develops a leak – any of these can cause sudden microbiological contamination. Because bacterial contamination is not a constant, the water test result is often reported as not detected. FOR NOW. That can change tomorrow, which is why the public health recommendation for regular testing is at least annually.
For disinfection, it is not just about selling to the need. It’s about selling to the risk. Both constant chlorination and ultraviolet (UV) disinfection are recognized by authorities like the EPA and Health Canada as effective means of disinfection. UV adoption, though, is on the rise, because under normal operating conditions, it’s effective against a broader range of microorganisms, including protozoa, like Cryptosporidium and Giardia. It’s also a chemical-free, environmentally-friendly solution.
UV disinfection is as tried and true as chlorination.
UV disinfection is not new!
Chlorine has been widely used for public water treatment in the USA since the early 1900s, which speaks to the fundamental need for disinfection to protect health. But disinfection with sunlight has been recognized for centuries. The germicidal properties of sunlight were demonstrated by Downes and Blunt in 1877. Once it was understood that specific UV-C wavelengths are responsible for this germicidal activity, the technology was developed so that UV light could be used in a controlled and meaningful way. UV disinfection has been widely adopted in Europe and Canada for municipal and private water treatment. Advancements have continued making UV systems more compact and even more energy efficient over the years. Many municipalities around the world have overhauled their primary disinfection from chlorine-based to UV.
Furthermore, commercial pool operators, and private pool owners, are discovering the use of UV as an effective sanitizer. UV implementation on a pool or spa will allow the owner to drastically reduce the need for harmful chemicals, making the swimming environment safer and more pleasant.
UV technology is easy to explain!
Ultraviolet light is a sophisticated disinfection solution, but it doesn’t require an overly technical explanation. Light of a specific wavelength is passed through the water, inactivating any pathogens that are present. Because they are inactivated, microbes can no longer multiply, which means they can’t cause infection.
Pre-treatment requirements are straight forward!
For the best results and minimal maintenance, UV systems do require some pre-treatment. At the least, this includes a sediment filter, which is often included with the newer, high quality systems. Hardness, which is common in ground water, can be problematic and should be addressed by a water softener. There are many benefits to softening water, however, that can be readily appreciated by any homeowner. That leaves the matter of iron-bearing waters. For low levels, this may already be solved by the addition of a water softener. But beyond this, there are iron (and sulfur) treatment options that do not add noxious chemicals to the water. Oxidation does not have to mean chlorination. Even though residual chlorine can be easily addressed with Granular Activated Carbon (GAC) at the tap, more and more consumers are seeking chemical-free solutions. Why add something only to remove it again?
Multi-barrier approach addresses need for residual While generally not necessary for residential applications, there are times when regulations demand a residual disinfectant. Using a multi-barrier approach to disinfection can help reduce undesirable disinfection by-products (DBPs). The addition of UV will mean less chlorine is needed, reducing the potential for the formation of DBPs