Some phase one renovations to the Arthur wastewater treatment plant are going forward, ahead of the completion of an environmental assessment (EA).
The Wellington North public works committee approved two recommendations from public work director Matt Aston after an update on the EA on Feb. 9.
The Arthur plant is currently undergoing an EA to upgrade the facility, which is currently running over capacity.
“Phase one (of the upgrades) would be increasing the Arthur wastewater plant to a design capacity of 1,860 cubic metres per day and phase two would be to move the Arthur wastewater treatment plant to a design capacity of 2,300 cubic metres,” said Aston.
Phase one requires four capital upgrades or modifications to re-rate the plant, including sludge management, upgrading the liquid train process, replacing a sanitary force-main and constructing an equalization tank.
Phase one and two upgrades have a conceptual cost of around $12.9 million but could be higher, explained Aston.
The EA is expected to be completed this spring, he said.
Sludge management
Aston presented a report to the committee to ask for approval of part of the phase one upgrades. This includes improving sludge management.
Sludge is currently land-applied for disposal in the area, explained Aston, but the facilities are inadequate to hold sludge for both the interim capacity and the final capacity once upgrades are complete.
Four options were given to the committee from XCG Consultants, the company hired to complete the EA. Three options include capital projects that could bring a five-year cost between $2.4 and $5.3 million. The last option was to haul the sludge to Lystek International Inc. in Dundalk, at a five-year cost of almost $500,000.
The last option was recommended by staff and approved by council.
“It was recommended by XCG because there was no capital costs associated with that option,” said Aston.
While it was largely a financial decision, the selection “doesn’t preclude us from looking at investing in storage on site if we so choose, but we would have to go through a class EA process to add that additional storage,” said Aston.
The current EA does not have sludge storage within its scope, he explained.
Aston recommended to council that 50 per cent of the sludge generated at the Arthur plant be hauled to Lystek. This 50/50 split would mean approximately $35,000 per year in operating costs.
Fine aeration
In a second report, Aston asked the committee to move forward on a second improvement project as part of the upgrade.
The report asked for a fine bubble aeration system to be installed at the plant. The price tag is unknown at the present time, but is estimated to be over $75,000 and included in the total cost estimate of $681,000 for phase one common upgrades.
“The Arthur (treatment plant) has what they call aeration bays as part of its process … Right now today is what they call coarse bubble aeration, which injects some oxygen,” explained Aston.
“Basically fine aeration, what it will end up doing, is put more oxygen into the aeration bays and sort of encourage more micro organism activity to eat the sewage. It will basically just improve those aeration bays’ treatment capability.”
The committee approved Aston’s request to move forward with the detailed design work with Triton Engineering at a cost of $20,000.
Aston explained to the Advertiser that both the sludge management and fine bubble aeration upgrades could be done at the plant “because there’s no sort of capacity or change to the tanks, it’s not something we have to wait necessarily for the class EA to be completed.”
The other processes, however, would have to wait for the completion of the EA.
Capital work
Aston also submitted an EA update report for information. The report contained the results of the XCG evaluations of two pumping stations in Arthur.
“They concluded that the Wells Street pumping station had adequate capacity to handle expected sewage flows to 2031, and they concluded that the Frederick Street sanitary pumping station does not have adequate capacity to handle projected or forecast sewage flows to 2031,” said Aston.
“They’re recommending about a $2.9-million upgrade project to the Frederick Street pumping station to meet those 2031 flows.”
This expense would be beyond the costs estimated for the upgrades to the WWTP, he explained.
