Massive Tunnel Form Underway

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Yet another milestone has been met on the site of the Tunnel Dewatering Pump Station and Enhanced Clarification Facility project at the Blue Plains Advanced Wastewater Treatment Plant in Washington, DC! Formwork was set into the screen shaft to extend the 23-foot-diameter tunnel, which conveys combined stormwater and sewage to the plant for treatment. PC crews extended the tunnel section 19 feet to bring flow through the screens and into the 156-inch suction manifold located in the Tunnel Dewatering Pump Station.

This $215 million design-build PC/CDM joint venture project includes the design and construction of a 500-mgd tunnel dewatering pump station and 225-mgd enhanced clarification facility. Work includes the conversion of a deep shaft measuring 132 feet in diameter by 159 feet deep; a ballasted flocculation clarification process including ACTIFLO® high-rate clarification process, fine screens, grit removal and disinfection and dechlorination facilities; installation of six 3,750-horsepower pumps; and conversion of a secondary shaft measuring 76 feet in diameter by 130 feet deep into a surge and screening structure.