Corix is cutting its teeth on Dawson City’s new sewage system.
Last week, the Yukon government signed a $24.8-million contract with the BC company to install a deep-shaft wastewater system in the town by 2011.
It’s a first for Corix.
“We own and operate upwards of 100 wastewater plants around North America,” said Corix director of sales and marketing, David Speed.
But none of those plants use deep-shaft technology, he said.
“This is the first one.”
Usually, sewage is stored in lagoons.
But Corix is going to pump Dawson’s waste underground.
The sewage shafts are 100 metres deep, said Speed.
“Wastewater treatment stems on getting oxygen into the wastewater so it can feed the bugs that eat up the bad stuff and create the sludge,” he said.
“The way the system is designed, instead of having a whole bunch of high-powered blowers that bubble air through a big basin on the surface, we just use a compressor that bubbles air into the bottom of the shaft.”
Because the shafts are underground, the sewage system has “a much smaller footprint,” said Speed.
Deep-shaft technology has been around for more than 30 years, but there are very few of these plants in North America.
“There’s some in central Canada—just in Manitoba,” he said.
But the one in Portage la Prairie was shut down.
“There were design issues,” said Speed.
“McCain (Foods Ltd.) put in a potato plant and it overloaded the system.”
The other deep-shaft sewage treatment plant is in Virden, Manitoba.
“With Virden there were some other problems,” said Speed.
Virden’s deep-shaft system, installed in the late 1970s, only worked for a few years, said Virden’s manager of works and utilities, Cornie Peters, in a previous interview with the News.
Virden is in the process of replacing the system with more conventional sewage treatment, said Peters.
The deep-shaft technology sounded promising, and Virden hoped it would be cheaper to operate, he added.
But it just can’t meet Canada’s waste-effluent standards.
“It’s way over,” said Peters.
Virden’s deep-shaft system can’t even remove the nitrates and phosphates from dish soaps, he said.
“This system is incapable of it.”
Corix wasn’t involved with that project, said Speed.
It was Noram.
Noram has partnered with Corix for the Dawson project.
“Noram would be better able to speak to it, but my understanding is that the (Virden) plant ran fine for the first 20 years of its life, and then there were some maintenance issues,” said Speed.
“I really don’t know the story firsthand.”
The fact that Corix has never built a deep-shaft sewage system is not an issue, said Yukon Public Works project manager Catharine Harwood.
“It’s not a worry to me because it’s a team approach,” she said, from Dawson.
“Noram is such a large partner, and Corix has things Noram doesn’t, so they complement each other.”
Noram’s shoddy track record in Manitoba is not a concern either.
“There are over 500 (deep-shaft) installations around the world,” said Harwood.
“Canadians tend to want to see something in their country because we know what our effluent standards are—we don’t know what the Chinese and Finnish ones are—but that doesn’t mean that the technology can’t be shown that it will do what we require.”
The technology is complex, said Harwood.
“So we can’t just make the blanket statement and say, ‘If it works in Finland, it works in China and in Canada,’ because you need to tailor each system to the place and the permit requirements.”
The deep-shaft technology is flexible, she said.
“It’s not something that rolls off a truck and is plunked down in Dawson; this is something that needs a high level of development, and what we’re going to be doing now is finishing off the design and making sure it matches our needs.”
Whitehorse’s Ketza Construction Corp. was the only other company that bid on the Dawson sewage project.
It proposed a $16.5-million biological treatment plant that uses micro-organisms to digest the contents of sewage.
There are 800 of these biological treatment plants in operation, and 100 of them are in the North.
But the local construction company failed to meet the technical requirements, according to a rejection letter from Public Works.
Ketza, which spent six months and more than $100,000 preparing its bid, immediately appealed the government decision.
“Every week I called to follow up on the appeal,” said Ketza owner Peter Densmore on Tuesday.
And every week, Densmore was told it was being processed.
But on Friday, several months after filing the appeal, Densmore was informed there was a conflict with the appeal board and the process was starting over.
“We have to make sure that the bid-challenge committee is made up of private, upper-sector people who don’t have any conflict in the project,” said Harwood.
Although the deep-shaft system is going to cost $10 million more than the biological treatment plant Ketza proposed, it might save in energy costs.
“It uses up to 50 per cent less energy than a conventional wastewater treatment system, just because of the way air is introduced,” said Speed.
“And with a smaller building footprint, you also end up using less energy.”
The yearly operating costs are estimated at $280,000, said Speed. “And a big chunk of that is the cost of having a city person on staff.”
“It would have been way cheaper to install an MBR system for about $5 million,” said Mike Harkin of Pinnacle Environmental Technologies Inc., a Canadian company that specializes in wastewater treatment.
Harkin installed a sewage treatment system in Eagle Plains last fall.
“Dawson’s not very big,” he said.
With an MBR (membrane biological reactor) system wastewater is cleaned and then pumped into the river.
“It would be cleaner than the river water,” said Harkin.
But the Yukon government didn’t go that route, said Harwood.
Membrane biological reactor technology “produces a very high-quality water,” she said.
“You can produce wastewater that’s drinkable—but that’s not where we are.
“We have a great proposal and a great team and the confidence this is going to go really well.
“I think everyone is excited this is finally moving forward—attempts to derail it or cast aspersions on the evaluation team are unfounded—the Yukon government and the city of Dawson have done a fantastic job managing this project.
“I think it’s just disappointing that people in this small territory like to cast stones.”
Contact Genesee Keevil at