The City of Castlegar has come up with a short-term solution for problems plaguing its south sewage treatment plant while it looks for a longer-term fix.
Council awarded two contracts this week: $181,000 plus tax to Fournier Industries for immediate biosolids dewatering and $271,000 plus tax to Kerr Wood Leidal Associates Ltd. to come up with something permanent.
In 2022, the Ministry of Environment told the city its stockpile of biosolids at the treatment plant didn’t comply with its permit. So the city installed something called a geotube system. Despite what project manager Anne Simonen called “a year of troubleshooting with the consultant and supplier,” it never worked properly.
While it was thought the geotubes would also do away with odours from the plant that irritated Woodland Park residents, the system actually made the smell worse. The city has since reverted to mixing partially dewatered biosolids with wood waste before hauling them away for disposal.
This year the city put out a call for consultants to provide short-term biosolids dewatering systems. They received four bids. Fournier, a Quebec company, had the low bid. The contract is for three months with the possibility of three six-month extensions. The prices that bidders provided were based on a three-month term plus a single six-month extension.
Fournier will provide a rotary fan press dewatering system, which relies on pressure and friction to squeeze water out of the sludge.
Simonen said the company has tested its system on a sludge sample the city provided and was produced a much lighter biosolid. “The results indicated excellent potential for successful dewatering with the use of a rotary fan press,” she wrote.
The trailer-mounted system can be installed on site without other upgrades and can unload dewatered biosolids into a bin, Simonen added.
She said the data they gather during the project will help inform a longer-term solution. If the short-term fix goes well, the permanent solution may employ similar equipment.
“Rather than jump into the next fix, we wanted to take a step back and figure out the best solution,” she told council.
Kerr Wood Leidal Associates of Nelson was the winner out of five companies that submitted bids on designing the longer-term solution. The same company is expected to carry out their design at a cost to be determined later.
City manager Chris Barlow stressed that while the project may result in reduced odours, that isn’t its primary purpose.
“This project, first and foremost, is a biosolids handling project,” he said. “In no way are we saying this is an odor mitigation project. That hopefully is a downstream impact, but we can’t be sure until we’ve seen the technology work.”
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