Glenmore and Bearspaw Plant Upgrades, Calgary, Canada


Bearspaw

Completed in 2011, the seven-year programme of upgrades at Calgary's two water treatment plants, Bearspaw and Glenmore, will now enable the city to meet the needs of its projected population to 2025 and beyond. The Glenmore water treatment plant was commissioned in early 2011.

The project involved improvements to the pre-treatment, filtration and chemical systems at both plants, together with upgrading residuals handling. At the Bearspaw WTP, the programme included the addition of ultra-violet disinfection, while at Glenmore the liquid chlorine and de-chlorination systems, taste and odour controls were modernised and upgraded.

The project cost was C$300m; Bearspaw accounted for C$170m of the budget, with the work at Glenmore accounting for the remaining amount of C$130m.

Project drivers - regulatory standards, rising population

The two main drivers on the project were the increasingly stringent federal and provincial Canadian regulatory standards, coupled with the area's rising population, making an upgrade to the existing facilities inevitable.

"Clarified water from waste is recycled to the pre-treatment phase, where solids are dewatered by centrifuge, before being shipped."

In addition, the city was committed to achieving a policy of zero discharge into the Elbow and Bow rivers by 2010, with waste streams treated and recycled on-site and residual solids removed to landfill.

The Glenmore facility - located on the Elbow River - was originally constructed in 1933 and subsequently expanded twice, in 1957 and then again in 1965. Set beside the Bow River, Bearspaw, the city's second WTP, was built in 1972 - seven years after Glenmore's second expansion - and was last extended in 1984.

High turbidity during spring runoff had historically been a particular problem for both plants, with levels in excess of 1000 NTU often causing a temporary overload of the sedimentation basins and filters, forcing the reduction of treatment capacity to preserve drinking water quality.

Between 2001 and 2003, a comprehensive review of the water supply infrastructure determined that extensive work was needed at both plants to meet future needs. The seven-year scheme of upgrades began with the provision of a new sodium bisulphite de-chlorination facility and the installation of potassium permanganate oxidation at Glenmore, while at Bearspaw improvements were made to the residuals and filter-to-waste systems.

Bearspaw WTP upgrade details

"The project involved improvements to the pre-treatment, filtration and chemical systems at both plants."

The Bearspaw plant upgradation was completed in 2009. The upgradation work comprised of six elements - a residuals treatment facility, a filter-to-waste-recycling system, potassium permanganate dosing, a pre-treatment facility, filter upgrades and UV disinfection. The upgradation has increased the plant's treatment capacity to 550 million litres a day (mld).

The residuals treatment facility, which entered service in 2007, significantly enhanced the treatment of waste streams from the treatment process.

Clarified water from the waste is recycled to the pre-treatment phase, where solids are dewatered by centrifuge, before being shipped off to landfill.

A new de-chlorination facility has been installed to avoid the possible need to discharge chlorinated water into the river in the event of an emergency.

The new potassium permanganate system provides an alternative to chlorination prior to pre-treatment, oxidising raw water compounds and helping overcome taste and odour problems, while filter upgrades were upgraded to improve both backwash efficiency and performance.

Upgrades to the Glenmore water treatment plant

Glenmore's upgrade encompassed eight components, five of which - residuals treatment facility, filter-to-waste-recycling system, potassium permanganate system, a pre-treatment facility and filter upgrades - it shares in common with Bearspaw. The remaining project elements at Glenmore called for treatment stages employing sodium bisulphite, sodium hypochlorite and powdered activated carbon.


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Installing both sodium bisulphite and sodium hypochlorite systems at the plant is principally to improve employee safety and enhance environmental protection, by removing the on-site need for sulphur dioxide and chlorine gases respectively.

The final part of the planned scheme - the powdered activated carbon (PAC) system, which entered into service in late 2009 - was selected to complement potassium permanganate dosing as a further method to deal with the taste and odour issues specific to Glenmore water.

By 2010, the penstock and Dow Valve refurbishments at the Glenmore plant were completed. The filtered water pumping station and renovation of office buildings have also been completed.

Both plants have adopted the same solution for the turbidity problem, using sand ballasted clarification - opting for Veolia's Actiflo system, based on its high settling rate and compact footprint. Microsand acts as a seed for floc formation, simultaneously enhancing flocculation while adding ballast to encourage fast settlement, leading to a turbidity removal efficiency, which typically exceeds 90%.

Bearspaw has six clarifiers installed with a total capacity of 586,000m³/d. Glenmore was equipped in two phases, the first installing four units with a capacity of 400,000m³/d, followed by two more to bring this up to an eventual 550,000m³/d. These systems, which are part of the new pre-treatment facilities, will effectively remove turbidity and organics prior to the filtration process.

Key players involved with Calgary's project

The plants are owned and operated by the city of Calgary. The main contractor on the upgrade project is PCL Construction, with Associated Engineering acting as the principal consultant. Veolia provided the clarifier technology, with John Meunier supplying the clarifiers to the project.

The city also works with groups such as the Elbow River Partnership and the Bow River Basin Council to protect and restore the watersheds and ensure the high quality of the raw water sources.


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