The city will spend $300,000 on an upgrade to its main sanitary sewer system.
The lift station, which is adjacent to Home Depot, is the largest in the city’s sewer network and handles the majority of the city’s sewage.
The lift station has three pumps which are controlled by the amount of sewage that flows into them and are operated by on/off controls.
Jason Hartley, the city’s capital works manager, said that type of control regime is limiting the ability to control the discharge rate into the city’s Norm Wood Environmental Centre where the waste is treated.
“The pumping system is not operating in an efficient manner as the pumps are cycled on/off at set points that can result in large surges being sent to the treatment facility,” Hartley said. “This surging flow…during high peak can cause effluent to be released to the marine environment without adequate treatment.”
The $300,167 upgrade will add an additional jockey pump and install variable frequency drives which will allow the city to control and adjust the speed of the waste being pumped to the treatment centre.
“Overall this project will result in increased system efficiency, reduced component wear and optimized energy consumption,” Hartley said.
At last week’s Monday meeting, city council awarded the project to Ridgeline Mechanical Ltd., with the money to come from the city’s sewer reserves. The project is budgeted for in the city’s 2015-2019 capital plan, in the amount of $500,000.
Council chose Ridgeline to undertake the work after city staff recommended against giving the contract to the lowest bidder. Hartley said the recommendation was made following a review by the project team that included independent legal advice from Peter D. Johnson Law Corporation.
“It was concluded that the lowest priced tender from Archie Johnstone Plumbing & Heating (at $283,750) was found to be materially non-compliant with the tender requirements,” Hartley said. “The next lowest tender from Ridgeline Mechanical was found to be compliant with the tender requirements.”
The budget for the project includes the $300,167 to Ridgeline for construction, as well as $109,953 for engineering, contract administration and inspection, and another $61,518 (15 per cent of the project’s value) to be set aside as contingency in the event of cost overruns.
All totalled, the project comes in at $471,638, slightly less than the $500,000 budgeted for the lift station upgrades.
The project is expected to take 26 weeks to complete.
Hartley said installation of the pumps and frequency drives is scheduled to begin in the second quarter of 2016 when sewage flows begin to ease because of reduced impact from winter storms and inflow and infiltration of storm water.