SUSTAINABILITY SPOTLIGHT
ALCOSAN Takes Major Step Towards Increasing Treatment Capacity
October 14, 2025
Work is underway at the Allegheny County Sanitary Authority (ALCOSAN) to significantly reduce the flow of sewage-contaminated stormwater into the Allegheny, Monongahela, and Ohio rivers during rainfall. A crucial step in addressing this challenge is to expand the treatment capacity beyond the current level of 250 million gallons per day (MGD) at the 59-acre wastewater treatment plant located on Pittsburgh’s North Side. By expanding this capacity, we can better protect our rivers and improve the overall health of our environment.
A comprehensive $2 billion Clean Water Plan has been developed to enhance treatment capacity. Earlier this year, upgrades were made to the North End of the treatment plant to better manage increased water flows during rain events. The upgrades included the addition of two final clarifiers, a new chlorine contact tank, and a chemical storage building.
In January, ALCOSAN decommissioned its iconic original outfall, which was in operation since 1959. This celebratory, pivotal moment marked the transition to a new and improved final effluent location at the north end of the plant.
“The brand-new East Headworks Facility, which contains grit tanks and bar screens to help us separate the solids from liquid, is also a large part of increasing our capacity,” said Kim Kennedy, Director of the Engineering and Construction Division.
The treatment capacity will be increased to 480 MGD by the end of 2025 and to 600 MGD by the end of 2029. The work we do at ALCOSAN, Kennedy says, is a huge win for the region and for the health of our rivers.
“By increasing treatment capacity, more stormwater that has been mixed with sewage will stay within the system, reducing overflows in the region’s rivers and streams. Additionally, the more wastewater that is conveyed to the treatment plant means less overflows in the rivers during wet weather events, leading to a cleaner and healthier river system.”
While she recognizes the significant progress we've made, she emphasizes that there is still important work to do.
“Looking ahead, we will build and implement a new wet weather pump station, which will convey about 120 MGD from the proposed regional tunnel system to our plant during wet weather events. We will also build another primary sedimentation tank to be prepared for the additional flows.”
The Construction and Engineering Division is responsible for the planning, design and project management of construction projects, as well as record-keeping and bidding procedures. She noted that her division is responsible for projects both inside and outside the plant, so their work truly touches all pillars of the Clean Water Plan.
“ALCOSAN’s commitment to cleaner rivers and a brighter future for Allegheny County is a team effort, and it wouldn’t be possible without our partners in the 83 municipalities we serve,” stressed Kennedy, who earned a BS in Civil Engineering from Bradley University and MS in Civil & Environmental Engineering from the University of Pittsburgh.
ALCOSAN received the Employer of the Year award on February 22, 2025, from the American Society of Civil Engineers (ASCE) Pittsburgh. On March 20, 2025, the Environmental Compliance Facility (ECF) and Garage at ALCOSAN won the 2024 Environmental Project of the Year award from the Engineers Society of Western PA (ESWP).
Leave A Comment