Winnipeg Water Treatment Plant
On December 10, 2009, the City of Winnipeg’s new $300 million, state-of-the-art drinking water treatment plant began sending treated water to homes and businesses. The water treatment plant is the largest infrastructure project the...
On December 10, 2009, the City of Winnipeg’s new $300 million, state-of-the-art drinking water treatment plant began sending treated water to homes and businesses. The water treatment plant is the largest infrastructure project the city’s Water and Waste Department has undertaken since the Shoal Lake aqueduct was constructed 92 years ago.
The plant is approximately 12,000 square metres in size, is expected to last about 75 years, and can treat up to 400 million litres of water per day. Built on a site adjacent to the Deacon Reservoir just outside Winnipeg, the facility was 10 years in planning, and six years in construction. AECOM’s Winnipeg office, in partnership with CH2M HILL’s Calgary office, provided pilot testing, conceptual and detail design, and construction management.
The city built the plant to protect against waterborne parasites, meet evolving Canadian Drinking Water Quality guidelines, reduce disinfection by-products, and improve the taste, odour and appearance of the water. The plant is achieving all these goals and is delivering high quality drinking water that meets provincial regulatory requirements and falls well within Health Canada guidelines.
Processing the Raw Water
Shoal Lake has been Winnipeg’s source of water since 1919. It is a large isolated lake located 136 kilometres from Winnipeg at the southeast corner of the Manitoba-Ontario border. Water flows downhill from Shoal Lake through an aqueduct into four large reservoirs next to the treatment plant and then is pumped into two parallel treatment trains. The trains supply eight 3-stage flocculation tanks and corresponding dissolved air flotation (DAF) tanks. Ferric chloride is injected as a coagulant prior to flocculation and the DAF process.
The water then flows through two contact tanks where ozone — which is generated on-site — is injected to provide disinfection, improve filter performance and improve taste and odour.
Sodium bisulphite is used to remove any residual ozone before the water enters eight biologically activated carbon (BAC) filters.
The BAC filters remove particulate material and promote the growth of beneficial microorganisms to further reduce contaminants. The water then flows into a chlorine contact chamber. Here sodium hypochlorite — also generated on site — is injected as a disinfectant. Finally the water moves through a clearwell to the existing pumping station and UV disinfection facility, ready for distribution to the city.
The plant has a highly automated system that monitors and controls a wide variety of instruments, mechanical equipment and electrical equipment, including 40 processors, 140 pumps, 2300 valves, and 1400 instruments.
To ensure that the water supply is safe and reliable, the plant has complete standby power with three diesel generators that can provide 6 MW of power for 24 hours without refuelling.
Recycling the Residuals and Freeze-Thaw Treatment
One of the most important environmental features is the plant’s capacity to treat or recycle almost all the residuals from the process on site. Supernatant from filter backwash water is recycled back to the raw water cells for re-treatment as drinking water. The overall treatment efficiency of the plant is very high, making it one of the most water-efficient treatment plants in the world.
The thickened residuals from the process train are treated in ponds by a freeze-thaw process taking advantage of the Manitoba climate. The cycle takes place over several seasons and uses no power or chemicals. It produces dewatered solids approaching 50% solids concentration.
Managing and constructing this large-scale project was a huge undertaking. First, the site posed challenges for the design of the plant foundations as it is surrounded by large raw water reservoirs, the Red River Floodway and a railway. The team worked with the provincial authorities and Manitoba Hydro on the site layout, and they built on the existing infrastructure. Four bridges were constructed over the Shoal Lake aqueduct to protect it from heavy traffic and loads.
The project involved 56 contracts and over 2,000 construction drawings. On average, over 60 cubic metres of concrete was poured every day and there were approximately 360 workers on site during the peak construction period. At the time Winnipeg was in the throes of a huge construction boom and the local labour market was stretched over a number of large projects, including the expanded Red River Floodway, the MTS Centre, Manitoba Hydro Office building and a new airport terminal.
In 2011, the project received the Consulting Engineers of Manitoba’s top award, the Keystone Award.cce
Owner: City of Winnipeg, Water
and Waste Department
Prime consultants, testing, design
and construction management:
AECOM, Winnipeg (Ray Bilevicius, P.Eng, Tom Wingrove, P.Eng, Doug Taniguchi, P.Eng, Albert Li, P.Eng,
Bill Richert, P.Eng, Till Freihammer, P.Eng, Neal Toulson); CH2M HILL, Calgary (Paul Wobma, P.Eng,
Dave Taylor, P.Eng, Bill Bellamy, P.E.,
Paul Swaim, P.E., Quirien Muylwyk, P.Eng, Ken Mains, P.Eng)
Other key players: Neil Cooper Architect