Multi-billion-dollar ALCOSAN wastewater project finally underway

A multi-billion-dollar project to clean up Pittsburgh's rivers and streams has been talked about for decades. Now it's finally moving forward.

After two decades of debates and delays, it's about to become a reality: an expanded treatment plant and 16 miles of tunnels, catching billions of gallons of sewage-laced rainwater before it flows into rivers and streams. At $3.5 billion, when completed, it will be the largest public works project in the Pittsburgh region's history. 

"It is finally moving forward. We are out to bid for the Ohio River tunnel," said Kimberly Kennedy, ALCOSAN's director of engineering and construction.

Every time it rains, Pittsburgh's combined storm and sanitary sewers get overwhelmed and spill raw sewage into waterways. The catchment tunnels are designed to capture that waste during wet weather events and pump it to ALCOSAN's newly expanded treatment plant. 

Eventually, the tunnels will stretch up and down all three rivers, but the authority is now seeking bids on the first phase of the project, which is a 3.8-mile tunnel under the Allegheny and Ohio rivers from the 16th Bridge to the treatment plant. 

The bids will be opened in November and construction is expected to begin early next year. This phase is estimated to cost $800 million and will use a giant boring machine to tunnel 150 feet below ground, but will proceed along the route unnoticed by the general public. 

"Other than looking at it on our website and following our progress, you won't have any effects," Kennedy said. 

But there will be an impact on your wallet. The federal government is demanding the project, but the cost will be borne by the ratepayer. ALCOSAN has been raising rates 7% every year since 2019. The cost to the average household has gone from $381 annually to a projected $612 next year. 

The rates will continue to rise through the length of the project and don't include expected increases from your host water and sewer authority. But Kennedy says it will be worth it in cleaning and reclaiming our rivers and streams.  

"Sewer infrastructure is not necessarily something you think about every day but it's a really important component to the health of the community and our daily lives," Kennedy said.