Dr. Yaldeh Azimi with the POTs group of OCWA presented a review of options to address water treatment challenges for the Whitewater Region treatment plants, as a report of the functionality of the Cobden Water treatment plant.
They said the Cobden treatment plant is operating at about 50%.
The study was prompted due to a number of compliance issues with water quality, including community complaints about water quality.
“In July 2021 we’ve had some community complaints about coloured water issues, this was yellow-brown colour issues.” they said. “We’ve had some pink colour incidents that also resulted in a water colour incident.”
They said their comprehensive sampling of the water showed that the turbidity, or clarity, of the water had decreased and was “typical of sourcewater quality across the Ottawa Valley”.
“The plant could benefit from optimizing, that included the coagulants for organics removal.” Azimi said. “Current coagulents show optimal organics removal when dose is adjusted based on source water quality.”
They said that monthly jar testing of the water showed that they were ‘bang on’ with their adjustments of the coagulants.
They said manganese and iron, as well as algae can lead to discolouration and recommended frequent jar testing of the water.
“Manganese isn’t really an issue every year.” They said. “Every few years the manganese is at the elevated levels that you actually need to start the premanganate system to oxidize and remove it with the filters. This is not a system that needs to be continuously used.”
They recommended to reduce organics and reduce chlorine numbers after initial disinfection, both of which are currently being implemented since December of 2022.
After December 2023, they recommend testing to see if there are still elevated levels in the water, before going to long-term solutions, including removing precursors to discolouration.
Councillor Moore said it was “nice to see that OCWA is moving ahead and showing the solution.”
“I think it’s important to let the public know just what is happening.” Councillor Chris Olmstead said. “
Councillor Joey Trimm asked what could cause the decreased turbidity.
“When I think about it, it’s more about water entry and where it flows into the lake. There’s a lot of factors.
“Very slight oxygen level changes within your can affect whether your the manganese can show up in its particulate form, which can affect your turbidity number.” Sangeeta Choppra, Director with OCWA, said. “If you have a dryer season, it can impact both algae and manganese.”
Mayor Nicholson asked how the average amounts for the provincial standards were determined, which Azimi said that the averages were determined on a quarterly basis annually.
Mayor Nicholson asked the earliest they could implement a longterm decision once it was determined the short-term solutions weren’t working.
“It may take up to a year to implement.” They said. “Some of these need a little bit more investigation, but also implementing them will take a little bit longer because they will be categorized as capital projects.”
“A lot of these long-term ventures are capital expenditures.” Public Works Manager Lane Cleroux said. “We’ll ask if the POTs team and the local team maybe we can evaluate prior to our budget cycle, so we can start the process prior to our budget period.”
“If they don’t work, I want to immediately take the next step.” Mayor Nicholson said. “Can we have a plan in place for January so we don’t have to take a year?”
“Staff are working on departmental work plans for May so we can look at that.” CAO Ivan Burton said.
Chopra said that OCWA had experience with manganese
The report was received.
