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Pump station and clarification facility to pump and treat combined sewer overflows
The PC/CDM Joint Venture, which brings together the industry-leading expertise in water treatment facility design and construction of PC Construction and CDM Smith, has been awarded the approximately $215 million Tunnel Dewatering Pump Station & Enhanced Clarification Facility project for DC Water.
The design-build project will be constructed at the Blue Plains Advanced Wastewater Treatment Plant in Washington, D.C. The tunnel dewatering pump station (TDPS) and the enhanced clarification facility (ECF) are part of the larger DC Clean Rivers Project, mandated under a Federal Consent Decree between the U.S., the District Government and DC Water, to build tunnels to temporarily store combined sewer (sanitary and storm) overflows until they can be pumped to the treatment facility. Currently, rainwater from DC Water’s 725-sq-mile service area can overwhelm the system and treatment facilities with a diluted mix of rainwater and sewage, resulting in potential overflow into the Anacostia and Potomac rivers as well as Rock Creek.
Major project components include the construction of a 250 million gal per day (MG) TDPS which will pump a diluted mix of rainwater and sewage to the ECF. The new, 250 MGD ECF will utilize a ballasted high-rate clarification process. Treated water will be disinfected before discharge to the Potomac River. The TDPS and ECF will be expandable to 500 MGD in the future.
The design phase of this project will begin in August, with construction following shortly thereafter. The overall tunnel project for DC Water is expected to be completed by March 2018.
Since 2010, PC Construction has worked on four other projects for DC Water with a total estimated value of $375 million.
“The projects that make up the wet weather plan achieve both nitrogen reduction and CSO abatement, improving the health of our waterways and saving hundreds of millions of dollars,” said DC Water General Manager George Hawkins.