A 700-page report and the results of a 2021 municipal class environmental assessment for the Payette water system were presented to Penetanguishene committee of the whole recently.
A short slide presentation and overview of the findings and recommendations were provided in council chambers by environmental engineer Jane Wilson, of J.L. Richards & Associates.
While the town’s water system consists of three well fields, only the Payette Drive and Lepage wells are active.
In 1991, unsafe levels of trichloroethylene (TCE) discovered at the Robert Street wells forced the town to decommission the contaminated supply, where they have been carefully monitored since.
A 2022 report showed those contamination levels were decreasing and were expected to be safe for consumption in the next decade, which Penetanguishene council members were pleased to hear.
“The overall purpose of this study was to look at both near- and long-term ways of improving the security and redundancy of the town’s water supply,” Wilson told committee members.
“A key point about (the Payette and Lepage systems) is that they are located in relatively near proximity to the town’s industrial area. Also, there is a concern about potential contamination of the spill, were it ever to occur there.”
Five alternatives were shortlisted, but the recommendation of best option was ultimately narrowed to providing treatment at the Robert Street well field, up to the permit-to-take-water limit of 3,275 cubic metres per day.
“(One) key advantage of this option, compared to the option to construct treatment at Robert up to 6,500 metres cubed per day,” explained Wilson, “is that it could be subsequently expanded in the future. So, this option can be implemented now and then augmented by either additional treatment at this well … or even in the future, connection to Midland if that was something that wanted to be pursued by both municipalities as growth triggers required it.
“The capital cost associated with this option is $8.3 million … and the 50-year life cycle costing of $12 million.”
Wilson added the potential maximum day yield of the Payette water system is about 11,000 cubic metres per day, and that the Robert Street site “has the potential to supply that same amount in the future.”
Ontario Drinking Water Standards stipulate five micrograms per litre (μg/L) of volatile organic compounds, including TCE, is the threshold between safe and unsafe drinking water. And although levels are declining at the Robert Street site, TCE remains measured as outside the safety zone.
“The concentration of TCE contamination has declined over the last 20 years,” said Wilson, “from a high of around 50 μg/L to, in the most recent testing, less than 10 μg/L. The limit for drinking water is five μg/L, and so it is expected that over time this concentration would continue to decline naturally to below the maximum acceptable concentration.”
The proposed recommendation to treat for TCE would involve an advanced oxidation process to break the compound into less harmful molecules like carbon dioxide and water, while also treating other contaminants.
Wilson added the technology would be capable of reducing the TCE concentration to two μg/L and even lower, but chasing safer levels would require resizing of equipment from the recommendations in the report.
The presentation concluded with thanks from the committee of the whole, where the report was received and is expected to be addressed at an upcoming meeting of regular council.
The Payette water system secondary water supply class environmental assessment report can be located on the agenda page of the Town of Penetanguishene website.
The Robert Street well field pumping tests results report from July 13, 2022, with the thorough fall 2021 TCE and yield testing program report by Golder Associates, can be located on the agenda page of the Town of Penetanguishene website.
Information on comparable water quality summaries for previous years at the Payette supply can be found through the water page of the Town of Penetanguishene website.
Meetings of Penetanguishene council are held on the second Wednesday of each month, and can be watched live on Rogers TV cable 53, or on the Rogers TV website.
Archives of council meetings are located on the Town of Penetanguishene YouTube channel.
