Project Categories

View More

Bonnybrook Treatment Plant (Combined)

Calgary, Alberta

Contract Value:

$604.6 million

Prime Consultant:


Project Owner:

City of Calgary

Contract Format:


Contract Duration:


Bonnybrook is the City of Calgary’s largest wastewater treatment plant with an average flow to treatment of 396 ML/d and a peak capacity of 1,096 ML/d. Graham is currently executing multiple upgrade projects including the recently completed Headworks Building and the Plant B and C Secondary Treatment Upgrades.

The new headworks is designed for incoming wastewater flows up to a maximum wet weather flow of 1,390 ML/d. The structure is 35 m x 55 m and houses new influent screens, grit removal, grit and screenings handling equipment, truck loading facilities and all process piping and appurtenances.

The Plant B & C Upgrades include the addition of six new secondary clarifiers, installation of eighteen secondary clarifier mechanisms and upgrades to the RAS, WAS, electrical and control systems throughout Plant B and C.

Graham is the Construction Manager for The Plant D Expansion Project that will increase Bonnybrook’s treatment capacity by more than 30%, accepting an additional 135 ML/d average flow and a 352 ML/d peak flow. The scope of work for this contract includes the construction and commissioning of new primary clarifiers, BNR plant, secondary clarifiers, final effluent filtration, Thermal Hydrolysis Process and a new outfall to the adjacent Bow River. Upgrades to the existing digesters, biogas management and ultraviolet disinfection are also required to provide the increase to the required treatment capacity.

The Bonnybrook plant serves over 600,000 citizens and processes approximately 376,000 m3 (491,789 cu. yd.) of sewage a day. Once treated, the water is released into the Bow River, and the separated waste is recycled. Completion of this project will ensure the City of Calgary continues to be a leader in the field of wastewater treatment.