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Major infrastructure upgrades are in the works for the city of Portland’s two major wastewater treatment plants in a project that’s expected to last for six years.

Canada-based Stantec is serving as owner’s representative on behalf of the Bureau of Environmental Services for the work at the Columbia Boulevard Wastewater Treatment Plant and the Tryon Creek Wastewater Treatment Plant. Both plants are more than 50 years old and in need of reliability, efficiency and capacity improvements, according to Stantec engineers and city officials.

鈥淏oth of these plants are aged infrastructure,鈥� said Dick Talley, area manager for Stantec in Portland. 鈥淭he Bureau (of Environmental Services) here five or six years ago did an assessment in terms of age and reliability, and in terms of their treatment efficiency and capacity. What came out of that was a series of capital improvements the facilities were needing.鈥�

The Columbia Boulevard plant, near Heron Lakes Golf Club and Portland International Raceway, is the larger of the two plants and was completed in 1952. The Tryon Creek plant was built within the city limits of Lake Oswego and completed in 1965.

The two plants treat all of the city of Portland’s wastewater. Columbia Boulevard treats an average of 76 million gallons a day with a capacity of 450 million gallons per day, while Tryon Creek treats 6.5 million gallons per day on average, with capacity to treat 8.3 million gallons per day.

Talley compared the system to a root and branch map. Each building discharges to small pipes, which join larger pipes and eventually the wastewater treatment plants. The Columbia Boulevard facility discharges into the Columbia River, while Tryon Creek goes to the Willamette.

Stantec began working with the BES in August to oversee the projects. At Tryon Creek, a joint venture of Slayden and James W. Fowler Co. is serving as construction manager-general contractor. Black & Veatch and Carollo Engineers are the design engineering firms.

At Columbia Boulevard, Jacobs is on board as the design engineering firm. A CM-GC has yet to be selected.

Budgets have not been finalized, but hard construction costs are expected to reach approximately $80 million at Columbia Boulevard and $50 million at Tryon Creek, Talley said.

鈥淭hey’re big projects in terms of capital dollars,鈥� he said.

Construction isn’t expected to begin until mid-2020. Both project teams will face the complication of working while the plants run. Neither one can be taken offline.

At Columbia Boulevard, anticipated work includes improving secondary water treatment, rebuilding the odor control system and upgrading electrical systems.

鈥淎 lot of the electrical switchgear is 1950s, 1960s vintage,鈥� Talley said.

Tryon Creek needs a more thorough rebuild, including replacement of the headworks and primary treatment equipment, improvement of the secondary treatment and odor control processes and replacement of electrical components.

鈥淭he end result is the plant will have little more capacity, a lot more efficiency and be more resilient,鈥� Talley said.

Seismic work will also be done at both plants to ensure they can survive a sizable earthquake intact.

Stantec was selected to oversee the projects because 鈥渨e felt their team and the firm’s experiences around the world in supporting the delivery of large capital programs using alternative delivery will provide the highest value to BES,鈥� bureau program manager Muriel Gueissaz-Teufel stated in a news release.

Stantec is based in Edmonton, Alberta.