Kokosing is proud to partner with the Allegheny County Sanitary Authority on the CSO Bypass and Disinfection Project. This initiative is aimed at addressing overflow challenges within Pittsburgh’s aging sewer system. The system combines stormwater and sanitary sewage in a single network. While this works in dry weather, heavy rainfall overwhelms the system, causing untreated sewage and stormwater to flow directly into the Ohio River. These combined sewer overflow events pose serious health and environmental risks, contaminating waterways and threatening aquatic life. 

The CSO Bypass and Disinfection Project is expected to significantly reduce untreated discharges during storms by increasing treatment capacity. Kokosing is implementing key improvements, including eight new flow control structures, a modified chlorine contact tank, and a new influent conduit. A dedicated building for sodium hypochlorite storage will enable rapid disinfection, allowing treatment of up to 305 million gallons per day during peak events.  

Kokosing is executing this complex work within an active facility, sequencing construction in four phases to maintain continuous flow, working toward completion by September 2026. Beyond cleaner water, this effort will enhance recreation and support economic growth along Pittsburgh’s riverfront—marking a major step toward a healthier, more sustainable future.