Regional District of Nanaimo will spend close to $1 million to upgrade wastewater treatment tanks at the Greater Nanaimo Pollution Control Centre.
At their board meeting Tuesday, July 26, RDN directors approved a contract for $958,000 to Brentwood Industries Inc., to contribute replacement parts for three “grit and sedimentation tanks” at the facility on Hammond Bay Road in Nanaimo, according to a staff report.
The tanks have been in use since they were installed in the 1970s and ’80s, and serve to “settle and remove grit and other heavy materials from the screened raw sewage as part of the primary treatment … process,” said the report. Components are susceptible to abrasion and corrosion, necessitating replacement “to ensure continued asset reliability and plant performance.”
In an e-mail, Duncan Taylor, RDN engineering services manager, said the work is a planned “major maintenance refit,” which will include replacement of sedimentation and grit collecting mechanisms and restoration work for the tanks, which are made partially of concrete.
“Sewer gas (H2S) that is carried into the facility with the untreated wastewater is corrosive and erodes the concrete surfaces in the tanks,” he said. “The weakened concrete surface is removed and replaced to protect the liquid from penetrating the concrete and corroding the reinforcing steel. Once the steel is corroded and compromised, the repair cost is substantially more.”
Due to issues with procuring materials, the RDN is being proactive, with work scheduled for next year, according to Taylor.
“With long lead times for major equipment currently being experienced, we are purchasing the mechanical mechanism components to ensure they are on-site prior to the concrete restoration, which will take place in 2023 and 2024, as the work needs to take place in the summer months when the flow is reduced,” he said.
As per the RDN’s purchasing authority bylaw, the board had to give approval the expenditure as it had a price tag of more than $500,000.