Pittsburgh, PA - The Pittsburgh Water and Sewer Authority (PWSA) recently rehabilitated one of the largest sewers in its system, ensuring reliable wastewater service for portions of the East End of the City of Pittsburgh. This project, part of the Large Diameter Sewer Rehab program, used non-invasive technology to rehabilitate the pipe from the inside and prolong its life by approximately 50 years.
The 78-inch sewer, located near the Pittsburgh Zoo, was selected for rehab work due to the degraded condition of the pipe, observed during camera inspections. Carrying approximately 16 million gallons of wastewater per day, this sewer is important to the health of the overall system. The crews worked their way down the interior of the pipe, using manholes as access points, installing the liner and completing inspections of their work as they moved along. Lining sewers avoids costly excavations, especially on large-diameter sewers like this one, which is buried 75-feet underground.
PWSA documented the contractor team and their progress in this short video.
Rehabilitating PWSA's Largest Sewer Pipes
Large Diameter Sewer Rehab workers prepare pipe lining.
Sewer rehabilitation of this scale requires specialty expertise as well as a tolerance for small spaces and depths. Crew members are lowered into the pipe via manhole or other access point to apply the liner, with temporary retaining walls and bypasses located upstream of the work to stop any wastewater flows from interfering with their progress.
The Large Diameter Sewer Rehab Program involves trenchless rehabilitation of 36" diameter or greater sewer mains to restore structural integrity, reduce root intrusion, infiltration, and document the status of the pipe with camera and visual inspection. The pipe located near the Pittsburgh Zoo was one of three sites that received rehab work as part of this $1.4 million contract. Large diameter sewers are critical as they convey all the combined sewage from the upstream drainage area. Should they fail, the sewers can result in backups upstream or sewer overflows. They are very difficult to repair if they fail as they are typically much deeper than the upstream pipes and often run under critical infrastructure and environmental features, like busways, railroads, or streams.
“Essential sewer infrastructure can be located in deep and challenging locations, requiring our team to be innovative” said PWSA CEO Will Pickering. “This project is just one example of how PWSA can use new approaches to add life to the sewer and ensure that it continues to protect the environment and public health,” he said.
To learn more about PWSA’s sewer system and how you can do your part to protect these critical pieces of infrastructure, visit pgh2o.com/sewer.
