Developments in Residential UV Water Treatment Systems

Posted on March 27, 2014

Residential UV systems have seen significant changes over the past 15 years. Not only to the systems and the technology, but to the laws, regulations, and certifications that now apply to residential UV systems.


UV Water Filtration inactivates cryptosporidium

 cryptosporidiumIn the late 1970’s and through the 80’s and 90’s, residential UV systems were primarily used in recreational and some special applications where chlorine was not acceptable. In those days, UV systems were basically a light in a pipe and most UV companies lacked the scientific knowhow to test the systems properly.

In the early 1990’s, NSF International began to develop a protocol for testing and certifying residential UV systems. This was known as Standard 55. This standard had 2 parts to it and as of 1999, no company had been able to provide a system for testing that would meet the stringent requirements of the Class A protocol. Up until this time there were very few manufacturers of UV systems in North America for residential use.

In 1999, a UV task group was formed at NSF to update NSF Standard 55, changing the test organisms and the test protocol to provide more consistent execution of the protocol by multiple accredited labs. Although this was a good improvement, there are still inconsistencies in the execution of the protocol between various testing agencies.

In May of 2000, the Walkerton Ontario E. coli outbreak changed the UV market in Canada and the US forever. Seven people died and about 2,500 became ill when a chlorination system failed, causing concern for people both on and off the grid. People that knew they had well water and knew they were not treating their water had quickly decided they needed to have a UV system. The news of the Walkerton tragedy spread across North America, much like the Milwaukee cryptosporidium outbreak had done in 1993, where up-to 100 people in the Milwaukee area with compromised immune systems are believed to have died prematurely after being infected with Cryptosporidium. From this point forward, UV was looked upon more seriously as a solution to potential well contamination from bacteria and viruses.

About the same time, Trojan Technologies was completing some ground breaking research involving Duke, North Carolina and McGill Universities which would show that UV was effective against Cryptosporidium and Giardia, two protozoan cysts that had been previously considered resistant to UV and chlorine. Cryptosporidium and Giardia is still resistant to Chlorine. With UV water treatment, the research headed by Dr. Mark Sobsey and Dr. Karl Linden, proved that although the organisms were still alive, they were no longer able to cause illness – they deactivated the organisms. This news was revolutionary for the UV industry and all sizes of UV systems were being developed to meet the growing need of municipalities and residences alike. Dr. Sobsey and Trojan Technologies shared this information with over 100 people at the WQA convention in Long Beach California in March of 2001 and the interest in UV for residential applications in North America began to grow even faster.

During this hectic time, Trojan had been developing the latest advancement in UV technology for residential systems, the LPHO lamp. This was a lamp that would give 2 times the amount of UV germicidal light of the lamps previously used in the residential application. Trojan had used computational fluid dynamics to determine that by changing the flow pattern, increasing the chamber diameter and by using the LPHO lamp, a typical UV system could be reduced in length by 50% or more. This also meant that Trojan could achieve higher UV dose at typical residential flow rates. In November of 2001, Trojan became the first UV manufacturer to have a UV system certified to NSF Standard 55 Class A. In fact the Trojan UVMax Pro 7 and Pro 15 were both certified and later became the only two UV systems ever listed on the California Approved Devices list.

Jurisdictions like Ontario were now requiring NSF Standard 55 Class A UV systems to be installed in all places where the public may get water. This caused Ontario B&B owners, camps and other small businesses, to align with Safe Drinking Water Act (2002) regulation. In fact, the early regulations specified that the UV system needed to provide a certified UV dose trojan uvmaxof 40 mJ/cm2, which happened to be the level specified in NSF Standard 55 Class A. Now that there were UV systems certified to NSF Standard 55 Class A many jurisdictions like Ohio, New York and others began to adopt this as a requirement for applications where disinfection was needed and UV was the chosen technology. Not long after, a few competitors developed their own systems based on the design of the Trojan UVMax and there became more companies with NSF Standard 55 Class A certified systems.

Trojan again developing another leap forward in the residential UV system began development of a system with an even more powerful UV lamp, the amalgam PIP lamp. This lamp was revolutionary in that the amalgam was held in a cup at the base of the lamp and it had the ability to provide constant output over a wide temperature range for 24 months. The new lamp produced 4 times the amount of UV germicidal light of the original UV lamp. This meant even smaller systems, but more heat to manage. Trojan developed two temperature management systems. One that would allow air to travel by convection through the lamp sleeve during operation and a second one that would attach to the chamber to take the heat away through the use of a heat sink and a fan.

Trojan had not finished yet with their new Pro Series systems. They developed a device that would allow the end user to see the minimum UV dose the system was producing. Not only did it give a dose indication, this information could be collected on an SD card to allow a review of the system performance over a long period of time. They also introduced a software program that would allow users to view the performance on a graph, allowing them to predict when the sleeves would need to be cleaned to prevent alarms. After years of development, the new Trojan UVMax Pro 10, Pro 20 and Pro 30 NSF Standard 55 Class A certified system were introduced to the market.

In the past few years, many competitors have entered the North American residential UV market, leading to concerns by health officials that these systems may not be providing adequate disinfection, or may not have the appropriate controls in place to ensure the customer is aware of the system performance. Manufacturers have installed reminder systems to let end users know when they should change the lamp and some have monitors to let people know when the sleeve may need cleaning. This is still an issue for Health Canada and there is an ongoing discussion between manufacturers and Health Canada to determine the right balance of safety and affordability. In Canada, CSA B483.1, which regulates water treatment devices, has recently been included in the national plumbing code.

Meanwhile, Trojan’s residential business unit, VIQUA, continues to pursue the technical innovation of the past, recently adding to the UVMAX Pro Series. VIQUA have developed a flow meter to monitor the flow rate in the UV system. The computer system, built in, takes the flow rate information and the intensity monitor information to provide a “real time” UV dose tsterilight-cobalt-170x3002hat will always be above 40 mJ/cm2 or the system will go into alarm. Again, the end user can see the UV dose on the Commcenter and can gage when the sleeve will need to be cleaned. This will lengthen the time between cleaning for systems that have minimal flow rates.

Future Thoughts on UV

What will the next 15 years bring. One can only speculate, but LED’s are on the horizon and how they will be incorporated into residential UV systems has yet to be determined. Intensity monitors will continue to improve. Companies with research and development groups that are capable of new and different ways to innovate will surely lead the way as they have done in the past.

This post was written by Bruce Laing as he prepared to retire from VIQUA.

Bio for Bruce Laing

VIQUA's Bruce Laing discusses Trojan UVMAX and SterilightBruce was with VIQUA for 14 years and during that time was involved in many facets of product and standards development. He has been the Chairperson of the NSF Standard 55 UV Task Group for the past 11 years and works closely with many industry leaders on the NSF Joint Committee. He is also a member of the CSA B483.1 committee. Over the past 11 years he has made 8 educational presentations at WQA Conventions on various topics and has written many articles for Industry publications. Bruce enjoys his 4 grandchildren, photography, golf and cycling.