Clean water, healthy living!

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Depending on the application, a more complex water treatment system might be needed with the UV filter at right typically being the last component in the system.

By Leah Den Hartogh

Water quality is an ever-growing concern for Canadians. As more and more boil water advisories are posted, the industry is working to get the word out that there are solutions for consumers.

“By the time you have a boil water advisory, you have already consumed the contaminated water,” noted Pieter de Vries, president of UV Dynamics, London, Ont.

Water treatment in residential applications can include a water softener, sediment filter, de-chlorinator, and the final point of treatment – the ultra-violet (UV) system. The UV system has become more prevalent since the increase of boil water advisories, said Shelley Peters, operations manager for the Canadian Water Quality Association (CWQA). It is most commonly found in rural applications but there has been more interest in applying them on municipal water lately.

These systems are comprised of a stainless-steel chamber, quartz sleeve, and a special germicidal ultraviolet lamp. To simplify it even more – “it’s a light in a pipe,” said John Cardiff, executive vice president, business development, at Canature WaterGroup Inc., Regina, Sask.

The technology isn’t new. UV systems have been around for close to 50 years and have become an important part of water treatment for a residential system. Canada has some of the leading manufacturers, serving the water quality industry worldwide.

Science behind the lamp

The obvious benefit of installing a UV system is to protect the homeowner from bacteria and viruses that get into the plumbing system. The ultraviolet light emits energy close to 253.7 nm (nanometers) into the passing water, which is the most effective wavelength for disinfection, reported Vikas Thusoo, vice president, product management, for Rainfresh (Enviroguard Products Ltd.), Richmond Hill, Ont. Germicidal UV light inactivates bacteria and viruses by instantly destroying their DNA and RNA respectively.

A sediment filter removes anything that might prevent the UV light from reaching the bacteria.

“For residential use, UV systems should be able to deliver a minimum of 40 mJ/cm2 (millijoule per square centimetre) dose at all times. To put that into perspective against common pathogens, to achieve 99.99 per cent inactivation, E.coli requires only 5.6 mJ/cm2. Salmonella typhi that causes typhoid requires about 8.5 mJ/cm2. Cholera requires 2.9 mJ/cm2, and hepatitis A virus requires 30 mJ/cm2. This makes UV systems very effective in providing safe drinking water,” explained Thusoo.

The effectiveness of the UV lamps diminishes over time. Most manufacturers recommend they be changed once a year. Many homeowners will ask their plumber to do it, providing a reoccurring service call. The entire process isn’t difficult, providing they have been installed correctly.

“When you install these systems, you have to basically give double the length of the stainless-steel chamber in height to ensure that you can take the lamp out of the chamber because it comes out the top,” said Cardiff. “If you don’t give yourself this room, you will have to disconnect the whole unit in order to pull the lamp out of it.”

Plumbers should also disinfect all piping with chlorine after installation to ensure that the piping downstream is clean.

Heat can spell trouble

It is important to note that the lamp on these systems is running continuously. This means that the water temperature can rise when the water is stagnant.

If the water has a high level of hardness, the heat from the lamp will cause the hardness to create scale on the quartz sleeve. This will stop the UV energy from emitting through the sleeve and it won’t disinfect the water. Therefore, in hard water areas, a UV system should be preceded by a water softener. Other water treatment products such as iron or tannin filters may be required as pre-treatment, depending upon the quality of the water. Regardless a 5-micron sediment filter should always be installed before the UV.

Size matters

There is a bit of leeway with sizing UV systems, but it is important to size it properly. Contractors need to know the maximum flow rate, the dose required, and the UV transmittance of the water.

In this system, the UV lamp is isolated so the bulb can be replaced without shutting off the water.

If the system is oversized, there is a bit more forgiveness. This will result in more contact time with the ultraviolet rays. The issue with this is that the flow meter might not detect flow and the light will be less effective. This occurs only when a dimmer is connected to the lamp, explained Paul Ethier, manager of water quality products for Watts Water Technology, Burlington, Ont.

Under-sizing is more troublesome. The water’s contact time with the ultraviolet lamp will be too little and the system wouldn’t be effective, allowing unsafe water to pass the lamp. Bacteria also has the ability to swim and migrate upstream. The UV, for all intents and purposes, in an oversized system will do the job. There might be a higher cost to the consumer and the consumables are going to be more expensive on a larger system,” added Ethier.

PEX versus copper

UV systems can work with any type of pipe. “In terms of PEX or copper, you can use both. The one thing that you will see on the UV is that it’s a good idea to maybe not use all plastic, especially on the elbow joints leading into the system, because it can degrade the PEX over time,” said Brock Lupal, vice president of business development at Luminor, Guelph, Ont. He adds that there are pros and cons to each type of pipe.

When it comes to getting rid of these lamps, it is important to go through the proper channels to ensure that they aren’t just ending up in landfill sites. The lamps, when recycled, “needs to go someplace they will crush them up and collect the metals out of the system,” explains de Vries.

UV systems currently fit into the NSF/ANSI 55, class A or B, and CSA B483.1 codes in Canada. Class A are the products found on private water supply lines typically used in well or surface water; Class B are products used with municipal or previously treated water. CSA B483.1 is the standard in Canada for drinking water treatment systems.

Getting smarter

The future of UV systems appears to be good. Like so many things in this industry, the products are making their way into smart technology – which includes smart home monitoring and alarms. “Canada is already a world leader in UV technology. While the fundamentals of the technology will remain the same, I think manufacturers will continue to make systems more energy-efficient and improve the customer interface,” said Thusoo.

The takeaway that plumbers should always remember is to test the water before running the UV system. Minerals and sediment can affect overall performance. It is also important to make sure the other parts of the water treatment unit are working properly.

“Any plumber who adopts water treatment in their suite of services will find it is greatly rewarding and gets you one more point of contact with your customers,” added Ethier.

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