Editor’s note: a previous version of this story had the wrong number of years that the South Treatment Plant in Renton has been in permit compliance. It has been updated.
The sewage pipe project on Logan Avenue North might get smelly soon, but it’s not too likely.
After several weeks of prepping the site, which closed the intersection of Burnett Avenue North and North Sixth Street, the project will start pumping millions of gallons of wastewater that goes through the Eastside Interceptor, above ground in a temporary pressurized bypass.
Meanwhile, the interceptor, an eight-foot corroded sewage pipe that carries wastewater from the Eastside cities under Logan Avenue, will be repaired to extend the life of the pipe.
Because of its size it would be nearly impossible to replace due to the size of the line and disruption it would cause, which is why it’s being restored.
The bypass is scheduled to start running June 17, Stantec Project Manager and Principal Chris Ruiz said.
At that point, he said, that’s when odor would be most obvious. That’s why there are specific odor control facilities in place. One includes a misting facility which acts like rain to knock down pollution and tamp down odor, which can cover a broad area.
The bypass pumping will then continue until mid-October.
Stantec is a global firm, with an office located in Bellevue and is leading construction management of the interceptor project. The team at the office consists of environmental engineers, geologists and surveyors, and rehabilitate sewers, according to the company’s website.
Ruiz has been with the Bellevue office for 20 years and said this will be his largest underground project to-date.
“The key is to have all your ducks lined in a row and be ready to execute a well-written plan,” Ruiz said, adding they’ve been preparing since October.
At the May 20 Renton City Council Meeting, Vice President of the North Renton Neighborhood Association Nora Schultz said there have been a few bumps in the road.
“I don’t think this project was on anyone’s bucket list,” Schultz said.
But Schultz said the neighborhood association appreciated King County’s attempts to reach out to residents.
The project has a noise variance that allows them to work around the clock, except for Sundays. But Ruiz said he still wants to make sure they’re within the working hours. The current schedule looks like 7 a.m. to 7 p.m., with some work underground at night.
Inspectors will be onsite 24/7 in the event of damage to the pipe or the possibility of being overwhelmed with heavy rainfall. The inspector can then take immediate action to shut down the bypass, Ruiz said.
According to a weekly update provided through King County, the crews are finishing melding the temporary bypass. There will be multi-lane night closures from now until early June and a few temporary bus stop closures at North 10th Street and Logan Avenue North.
The bike lane along Logan Avenue North is also closed between Park Avenue North and North Sixth Street.
Burnett Avenue North will remain closed for the duration of most of the project, the Renton Reporter previously reported.
There’s a lot of steps involved in prepping the line; making sure the bypass can hold 45 million gallons a day and strong enough to withstand the pressure, and then to hold up against outside conditions.
The top of the eight-foot sewer pipe has been exposed, but required careful inspection, being so close to the Burlington Northern Railroad tracks.
After that, electrical pumps keeping the sewage moving require its own temporary power and backup systems. Then crews need to test it all before taking the interceptor out of service.
There will be three crews down in the interceptor pipe, and a few inspectors above ground.
Most of the bypass is above ground, but some street intersections and Boeing driveways required shallow excavation so the line could be buried below and covered with steel plates or asphalt, Ruiz said.
At the end of the project, Ruiz said they will restore the roadways, sidewalks, crosswalk markings or signage, curbing, gutters and landscapes disrupted.
“Everything will be restored to the previous condition or better,” he said.
This interceptor is critical to the King County sewage system, which recently received an award for the South Treatment Plant in Renton and the Vashon Treatment Plant.