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Bonnybrook Wastewater Treatment Plant Upgrades and Expansion


Photo Gallery - Unclassified

  • Rendering of the cogeneration plant expansion (based on preliminary design).
  • Aerial view of the proposed expansion and upgrade to the Bonnybrook Wastewater Treatment Plant
  • A S.W. panorama view of the proposed expansion and upgrade to the Bonnybrook Wastewater Treatment Plant
  • The proposed filtration treatment facility will improve the filtered effluent quality
  • The thermal hydrolysis process building will heat and pressurize solids to reduce the amount of solids generated by the plant. This plant is the first of its kind in Canada, and the second in North America

Project updates:

  • Flood protection berm construction begins spring 2017.


The Bonnybrook Wastewater Treatment Plant is the largest of Calgary's three wastewater treatment plants, with a capacity to treat the wastewater from approximately one million people. Learn more about the wastewater treatment process.

In recent years, Calgary and the surrounding regions have experienced population growth, which has increased the amount of wastewater requiring treatment by the plant.

Improvements to the plant

To meet the demand, the plant requires upgrades and expansion to increase the treatment capacity while maintaining the current level of wastewater treatment. Some enhancements area also being completed to improve the long-term environmental performance which will help protect the Bow River for future generations.

We are investing in a number of infrastructure improvements at the plant through 2022, including:

  • Lifecycle replacement of some existing equipment.
  • Upgrades to improve energy efficiency and environmental performance.
  • Expansion of treatment capacity through the addition of new infrastructure.
  • A flood resiliency component to prevent river back up and overland flow into the plant during high water events.

Overall project timeline

Construction will take place from 2015 to 2023.

  • Summer 2017 - construction for dewatering building.
  • Fall 2016 - flood protection berm work begins.
  • Summer 2016 - digester upgrades begins, with anticipated completion in summer 2022.

Project updates

Flood protection berm

To protect the plant from a potential future Bow River flooding event we are constructing a flood protection berm.

  • Construction of the berm, landscaping and construction of a new pathway adjacent to the plant on the west side of the Bow River will begin between spring 2017 - fall 2017.
  • There will be ongoing construction phases until 2022 to complete the project.

Dewatering building

A dewatering building is being constructed west of 15 Street S.E. This facility will dewater anaerobically digested biosolids. This will then be transported to the new Shepard Composting Facility being built in collaboration with Waste & Recycling Services. Approximately 10,000 dry tons of biosolids will be processed annually.

The commissioning of the dewatering building is scheduled to start in August 2017.

Electricity cogeneration facility expansion

One of the improvements to the plant, pending approvals from the Alberta Utilities Commission (AUC) and Alberta Environment and Parks (AEP), is the expansion of the existing power generating and heating plant that produces electricity and heat for the Bonnybrook Wastewater Treatment Plant. The applications to the AUC and AEP for approvals are anticipated to be submitted in March 2017.

The existing electricity cogeneration plant consists of three 1.6 megawatt (MW) reciprocating engine generators.

The expansion includes the addition of a new 4.5 MW gas combustion turbine and 0.4 MW steam turbine. This new cogeneration plant (named cogeneration as it will generate both electricity and steam from the same fuel source), will have a total generation capacity of approximately 9 MW.

Benefits of the expansion:

  • Results in a highly efficient and flexible system that will enable the plant to approach energy self-sufficiency.
  • Significant step forward in the use of biogas to efficiently generate steam and electricity for the plant.
  • Biogas is a renewable energy source that is produced as a by-product of the wastewater treatment process.
  • Use all current and future amounts of biogas fuel produced by the plant to generate steam and electricity.
  • It is expected to produce enough electricity to meet most of the electrical demands of the plant, and during low demand periods may export electricity to Alberta’s power grid.
  • A significant reduction in the emission of greenhouse gas (GHG) substances resulting from operation of the plant.


The new cogeneration facility will be located adjacent to the existing power generating and heating plant building and will fit entirely within the fence line of the Bonnybrook Wastewater Treatment Plant.


For general inquiries please call 311. For media inquiries please call 403-828-2954 or email