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.

“Both of these plants are aged infrastructure,” said Dick Talley, area manager for Stantec in Portland. “The 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.”

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.

“They’re big projects in terms of capital dollars,” 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.

“A lot of the electrical switchgear is 1950s, 1960s vintage,” 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.

“The end result is the plant will have little more capacity, a lot more efficiency and be more resilient,” 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 “we 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,” bureau program manager Muriel Gueissaz-Teufel stated in a news release.

Stantec is based in Edmonton, Alberta.

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One thousand new Portlanders each month. One million new residents by 2035.

Those are the official estimates. Now the region’s public officials must answer questions: Where will all these people live? How will they get to work? How will they get the services they need?

Right now, on a busy jobsite below a tangle of infrastructure where Interstate 405 meets Interstate 5 at the South Waterfront District, Portland General Electric is engaged in a major effort to support the massive growth expected. It involves complex methods and a tight timeline – a boring project in name only.

High power

PGE‘s power originates from a variety of sources. Wind turbines in the Columbia River Gorge, for instance, send power to plants, which transmit it to the edge of the city. There, the voltage is dropped to smaller amounts to serve smaller customers. Portland’s downtown and South Waterfront areas are currently fed power by a substation near OMSI on the east side of the river via underwater cables.

But four of PGE’s substations were built in the 1950s, and intended to last only 30 years. Also dating to the post-WWII era are four of the eight cross-river cables running from the Stephens Substation near OMSI to the west side of the Willamette River. But their age isn’t their only problem; water currents shifting the silts on the bottom of the river reduce stability and increase the chance of an outage. Maintenance on these cables – via SCUBA-wearing technicians – is also costly and difficult.

“It’s outdated equipment fed by aging lines to a real critical area, in terms of business activity, government, education, transportation,” PGE spokesman Stan Sittser said.

At $60 million, the Marquam Substation on Southwest Water Avenue will be Portland General Electric’s most expensive substation ever. It will be an open-air facility surrounded by a 12-foot wall. The equipment inside will be between 20 and 25 feet tall and visible from the street. The station will replace equipment that is 60 years old.

The project is, in a way, part of the Tilikum Crossing project completed last year. The span was built with transmission cables embedded inside, awaiting completion of the substation.

Two of the four 235-foot tunnels – or “feeder gateways” – have been bored to accommodate underground transmission lines, with work on the third ongoing. The tunnels are 48 inches wide and, when complete, will house the conduit and feeder cables that will hook to the PGE grid serving downtown.

At the site, there are two other major work areas – holes and the wall.

The holes and the wall

Electrical specialists Black & Veatch engineered the project prior to winning the $60 million bid. It’s their first time working with PGE.

Construction started in June, with work scheduled for completion in March 2018, and the substation expected to be online sometime in the second quarter of that year. PGE is considering another project component that would power Oregon Health and Science University; work on that would start immediately after construction at Marquam wraps.

The site has presented a few challenges so far, according to PGE project manager Ezra Richards. It formerly housed a Greyhound bus station and a hotel. In excavating the two pits, crews encountered soil contaminated by diesel from the gas station. That froze work for several days so testing could be performed and proper disposal of leaded materials could take place. Digging further down, crews ran into remnants from the old hotel, so they had to bring in an archaeologist to evaluate the materials.

“It turned out to be debris that could be disposed of,” Richards said.

With the pits dug, the task of tunneling 235 feet up the freeway hill could commence. Road realignments have buried a number of buildings and foundations along the former path of Sheridan Street, creating grist for Gonzalez Boring and Tunneling’s 48-inch drill bit.

“We’re now hitting foundations and drill piers and other concrete remnants, and that slowed the boring significantly as we’ve tried to go up,” Richards said.

The boring crew’s methods are surprisingly old school.

At 40 feet below ground, GPS technology is ineffective to position a bore. Instead, Gonzalez has been using a plumb bob and dead reckoning – no lasers or electronics. The first of the four bore holes came in just 3/4 of an inch off, and the second was just several inches off.

The head of the bore machine has a number of teeth. It literally cuts through soil and concrete and spins it out of the hole through an auger. Then an excavator is used to load it into a dump truck for removal. Earlier this month, workers were running into concrete pieces on hole three and were preparing to send a man up the hole to jackhammer the tunnel out and break that stuff up. The blockages were about 180 feet up the hole; the crewman would need oxygen pumped in.

“It’s kind of like deep sea diving,” Sittser said.

Vision zero

Safety is a buzzword across the entire construction industry, but due to the complexity and difficulty of this project, it’s a constant, overriding theme – as important as any of the other project goals, said Randy Franks, project manager for Black & Veatch.

“No one’s got hurt,” he said when asked how the project was going.

All site visitors – even journalists on a short visit – are required to take part in a 15-minute safety demonstration and sign a release form. There are daily safety meetings for all workers and weekly “tailgate” sessions with themed lessons. The only entrance to the jobsite, on Southwest Water Avenue, is kept chained during work hours; only authorized personnel are allowed in.

PGE requires visitors to wear the full gamut of personal protective equipment. Items include tough shoes with ankle support, but not necessarily steel-toe boots. Those can clip toes clean off when driven over by large equipment, explained Aubrey Hennigan, safety manager for Black and Veatch.

He tells workers to never walk past an unsafe situation, and to “make a difference today.” Every employee, from a laborer to a foreman, has the authority to stop work at the jobsite, Hennigan said. Being conscious of one’s surroundings is even more important on a crowded jobsite like the Marquam Substation, he said.

“There are pinch points everywhere,” he said. “If you’re at the edge of a track hoe, you’re going to explode before they know you’re under it.”

Rob Kirkland, safety director for Weitman Excavation, said the Vision Zero ethos – based on the plan to eliminate traffic fatalities – has spread to construction and is alive on this project.

“This is a change of mindset, a change of heart,” he said. “Zero – that’s the goal. We’re getting to zero.”

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