Guest Column - October 2005
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Highlighting UV Technology


The sound of splashing, laughing children. The clear, glistening water of a swimming pool. All are wonderful sights and sounds not found often enough across America. In most cases operators fight daily to keep pools and spas crystal clear, odor-free and bacteria-free. For decades operators have used chemicals to neutralize the effects of chloramines and bacteria. A costly battle in time and material. There is a solution.

For years Europeans have enjoyed the comforts of a simple, proven technology to keep their pools and spas cleaner, safer and reduced-chemical swimming environments. What is this technology? It is simply light.

Ultraviolet light to be specific. UV technology has been widely used for decades to sanitize water in our daily life. In the last 10 years, this technology was adapted to the swimming pool/spa industry in Europe to not only sanitize but also to control chloramines.

Chloramines, or combined chlorine as it is often referred to, is the constant nemesis of pool operators. In high-bather-load facilities, swimmers leave hair, oils, skin, makeup and anything else that washes off the body in the water. Little children often urinate or enter with diapers that when soaked leave behind chemical fluids and bacteria. All of this matter is attacked by chlorine that is injected into the water by various means. As it does so, it forms chloramines. This most commonly is noticed in indoor facilities by the odor associated with it. Other by-products are red eye, skin irritation, cloudy water, headaches and trouble breathing. The chloramines are "gassed off" and therefore most notable in indoor facilities where the gas cannot dissipate easily. It attacks the entire pool environment, creating serious maintenance issues.

However, they are found in outdoor facilities as well. With the high cost of energy associated with pool operations, pool blankets are widely used in some areas of the country. They create an even more challenging problem for the pool operators, trapping the chloramines under the blanket only to be released like a giant cloud when the blanket is removed. Not a fun task for the operator. Filtration and chemicals alone cannot effectively treat these problems. For years operators used the shock treatment method to reduce chloramines. This required them to shut down the facility until acceptable levels of chlorine, mandated by state health departments, were again measurable to allow swimming. Even this method of "super chlorination" is not foolproof.

In addition, nasty bacteria are showing up more and more in swimming pools, therapy pools and spas. Cryptosporidium and giardia, two of the most well-known, are both resistant to chlorine. After extensive studies accepted by the U.S. Environmental Protection Agency and the U.S. Centers for Disease Control and Prevention, UV has proven to be 99.99 percent effective to permanently kill all known microorganisms.

The technology of UV is a process where light in a certain electromagnetic spectrum, in the range of 200 nm (nanometers) to 315 nm, breaks down the DNA of the cell. Once the DNA is altered, it ceases to be able to reproduce. Organisms are destroyed and unable to cause disease. All this is accomplished on the first pass, which is why UV systems are put in line on the return line of the pool, treating all the water returning to the pool, not in a side stream application.

This technology was made possible in swimming pools with the advent of medium pressure lamps, producing the required energy (200 nm to 315 nm), that remain unaffected by water temperature variance found in swimming pools and spas. Only medium-pressure lamps emit wavelengths suitable for chloramines destruction. The additional advent of medium pressure lamps with high-power outputs resulted in compact/ high-flow units suitable for the swimming pool industry.

The systems are safe and simple to operate and create no by-products. Just turn them on, and the results are almost immediate. Maintenance is simple: Change a light bulb, usually once a year, every 6,000 to 8,000 hours, and replace the wiper seals usually every six months. The energy costs are minimal. Most systems operate at full intensity only when the pools are open.

Side benefits are a more chemically balanced pool. Although UV kills chlorine, the result is more free chlorine available to do its job and in fact less chemicals used overall.

Testimonials abound; once installed, pool operators usually are elated at the immediate results and the ease of operation. Basically leave it alone and let it do its job.

UV is not one of the passing wonders. It is growing in acceptance dramatically across the U.S. aquatics industry. It seems not if but when a facility old or new will add it to protect their bathers, equipment and structures.

With demand comes a surge in potential suppliers. There are several important factors that need to be considered before you invest in a UV system:

  • Is the UV system designed for swimming pool applications?
  • Is it NF50 and UL-listed for swimming pool applications?
  • Each UV unit must be sized for that particular pool or spa, taking into account bather load and turnover rates.
  • Is there local availability of parts and trained service people to maintain the unit(s)?


Ron George is the national sales manager for Engineered Treatment Systems. For more information, visit