Dawson sewage plant failing water tests

Dawson City's new sewage plant won't be handed over to the town just yet because treated water is not passing all of the required tests.

Dawson City’s new sewage plant won’t be handed over to the town just yet because treated water is not passing all of the required tests.

Operations of the one-year-old plant were scheduled to transfer from Corix, the contractor hired to build the plant, to the town last week.

But Corix has to pass water quality tests consistently for three months before it can say its work is done, according to the original $25-million contract with the company.

“Some of the parameters that are being tested are being met, and some aren’t,” said Catherine Harwood, who manages the project for the Yukon government.

The toxicity tests, including toxicity to fish, have been passed consistently, she said.

“We’re very happy about that. There have been no failures at all.”

The other tests judge the overall quality of the treated water, and include, among other things, a measure of the amount of suspended solids in the liquid.

“If it’s not floating or settled within five or six hours in its trip across the clarifier tank, then the solids want to flow out the back end of the plant, and that’s where we have the test problems.”

The contractor has made tweaks in the system over the summer in hopes that the problems would be worked out, but it’s a complex system, said Harwood.

“There were some modifications to the plant in June to make it run better in the long term, but that caused some short-term upsets, which again, because of the biological systems, means there is not an immediate fix available. We sort of have to manage the bugs and the sludge and the stuff that’s flowing around in the plant.”

Instead of a traditional lagoon system, the plant uses deep shafts drilled into the ground to process sewage.

Back when options were being considered for the new plant, some worried that this design was untested for the North, and had shown limited success elsewhere in Canada.

But there’s no point in second guessing choices that were made years ago, said Dawson Mayor Wayne Potoroka.

“You don’t get a mulligan on a capital project this big. It is what it is, and we have to make sure that it works.”

The city will take over the costs of operating the plant once it has shown three months of water quality tests with no issues.

Until then, Corix will pay for operations under the terms of the original contract.

The town has passed a council resolution expressing intent to hire the company to continue to run the plant under a new contract with Dawson.

The plant will likely be transferred to the town in the winter, when loads on the system are lower. Issues with the operation may pop again in the summer, when the population is higher and tourists are in town.

But there is also a two-year performance guarantee in the contract that would safeguard the city in case of ongoing problems, said Potoroka.

The Yukon government has been supportive in ensuring the transfer of operations goes smoothly, he said.

“We’re happy to have the assistance of the Yukon government. They have been helping quite a lot. They’re not walking away. We’re hearing that from those officials, they’re not going to walk away on us. They want as much as anyone to make sure that they leave behind a plant that works and a plant that’s affordable. It’s nice to have that on your side.”

Corix could not be reached for comment by press time.

Contact Jacqueline Ronson at


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