16th Canadian National Conference on Drinking Water – Intelligence Bulletin #3

Bulletin # 3 Tuesday October 28


With over 60 Sessions to be presented over the three-day Conference, yesterday started the Event with a vision for the coming years that “safe drinking water that meets all Regulatory Standards will not be enough to meet future needs.”

In this respect the incidence of Legionella was a theme in many different presentations, as was the importance of standards for maintaining a residual, regular monitoring and managing to a specified set of data requirements.

Some observations from those presentations in which AVIVE™ has strong interest:

Microbiology of Large Buildings

– presented by Susan Springthorpe, University of Ottawa

Large buildings pose unique challenges with respect to potable water management due to their complex air and water systems, repairs and changes to systems and the building itself, lack of understanding of systems, difficulties in maintaining consistent water temperatures within ideal ranges, and a greater number of dead legs. Note that every tap is a temporary dead leg where people regularly come into contact with water. Disinfection can sometimes select for the toughest, opportunistic bacteria species such as legionella in the water. In addition, dead bacteria can be a source of food for surviving bacteria. Legionella in particular have been shown to be adept at adapting and resisting interventions. Mycobacterial species can compete with legionella and an inverse relationship between concentrations of the two has been found.

Legionella: Experiences in Managing Pathogens in Large Buildings in Quebec

– presented by Michele Prevost, Ecole Polytechnique de Montreal

Quebec City has experienced outbreaks of Legionnaire’s disease on at least two occasions: 1996, 2012. An outbreak also occurred in Toronto at the Seven Oaks home for the aged. Cooling towers are a serious, potential source of Legionella in buildings. Proper monitoring should be performed and detailed records should be kept. Hot water systems also pose a risk. Temperatures would ideally be kept higher than 70°C, but this poses a scalding risk. Main recirculation water should be kept above 60°C and branches and point of use kept above 55°C. Trade-offs for energy conservation (i.e. lowering temperatures, or not heating recirculation water during the night) must be very carefully considered. Currently, a bi-weekly shock treatment of water or HVAC systems is often done using various chemical products. Good results are recorded immediately after such treatments, but bacteria levels quickly return to pre-treatment levels within approximately 48 hours. Electronically activated thermostatic faucets (motion sensor taps) are being installed more and more often because they reduce scalding risk. However, they should be designed with low mixing volumes to avoid large volumes of stagnant, warm water. The motto should be: keep it simple and small and only use these types of taps when absolutely necessary.

Considerations for Legionella in a Drinking Water Safety Plan

– presented by Nichloas Ashbolt, University of Alberta

Legionnaire’s Disease attack rate in hospitals is higher than most other pathogenic bacteria. This is made worse by the susceptibility of vulnerable populations. Legionnaire’s and non-tuberculous mycobacteriums (NTM) make up the lion’s share of drinking water related hospitalizations in the US. Stagnation of water can lead to amoebas which act as a Trojan Horse for Legionella. Amoebas, in turn, can be found within biofilm as it develops in plumbing.

Reducing risk:

  • Water temperature is important and should be kept lower than 25°C or higher than 60°C to reduce risk
  • Plastic plumbing is better than iron or copper
  • Maintaining proper residual concentration of disinfection chemicals
  • Point of use treatment units may be beneficial for at-risk populations
  • Total legionella concentration should be kept below 1000 colonies per litre

Legal Issues Surrounding Water Quality in Large Buildings

– presented by Jennifer Clancy, Corona Environmental Consulting, LLC

Legionella is the #1 waterborne disease in the US, and is often linked to management of drinking water after it enters a building. It is less often linked to the drinking water supply itself and this is not an adequate defense of poor building management practices if an outbreak occurs. Lawsuits connected to legionella-related illness are often settled out of court in order that defendant identities remain concealed and at the behest of insurance companies.

  • ASHRAE Guidelines 12-2000: best practices guideline for reduction of legionella risk. Currently working on a prevention guideline.
  • NSF: developed and teach a course on becoming a trainer for building water quality. The course is based on the HACCP plan. They are currently developing a standard for large buildings.
  • HACCP: has principles on a water safety plan
  • AWWA 2014: legionnaire’s disease communications document to help communication between utilities and their customers. Provide materials to cover a wide range of levels and education and for both large building and home owners.

State of Private Well Water Testing in Post-Walkerton Ontario

– presented by Allison Maier, Public Health Ontario

There are few well owners in Ontario who are bacteriologically testing their water as often as they should and the rates are declining. This poses an increased risk for outbreaks of waterborne illness. External factors appear to influence how often wells are tested (ex: owners with wells that test positive once will follow-through on subsequent, scheduled tests; those who don’t, won’t). General lack of compliance, variability in compliance, and insufficient support being offered through science indicates that more research and a better/stronger response are needed.

Today’s Sessions include a lunchtime presentation from Jim Shubat, SanEcoTec Founder and Chief Technology Officer; SanEcoTec’s Jay Whiteside and his presentation of AVIVE™ and the Future of Water; and Dr. Gordon Balch of Fleming College presenting AVIVE™’s use of HSP as a secondary disinfection agent for the reduction of potentially harmful DBPs. Other presentations will be looking at Emerging Issues and Challenges in Water Management – including Climate Change.

Look for reports on that and more in tomorrow’s Intelligence Bulletin.

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