ALCOSAN - North End Expansion
Allegheny County Sanitary Authority
Pittsburgh, Pennsylvania
- 1,000 linear-foot king pile wall
- 32,000 cubic yards of concrete
- 1,480 auger cast piles
- 68 rock anchors
- 150,000 cubic yards of excavation
Project Details
Mascaro received the general construction contract for the first phase of a major plant expansion at the Woods Run Wastewater Treatment Plant. The project includes the addition of two new circular final clarifiers, a new chlorine contact tank, a new chemical storage building, and a new outfall that will discharge the daily plant-treated flows into the Ohio River. This work is critical to meet the need to increase capacity from 250 million gallons per day (MGD) to 295 MGD by 2025.
The ALCOSAN plant is landlocked at its north end. There is minimal space for expansion between the railroad to the east and the Ohio River to the west. To create the real estate needed to build the two new clarifiers and the new chlorine contact tank, a river wall was constructed expanding into the river. The river wall spans over 1,000 linear feet consisting of 108 king piles interlocked, each measuring from 60 to 70 inches in diameter, with sheet piles.
- River and tunnel work
- Tank and building construction
- Chlorine contact building (10,000-square-foot)
- Chlorine contact tank (38,000-square-foot)
- One 150-foot diameter clarifier tank
