Project Info

  • Client DC Water
  • Location Washington DC
  • Cost $215 M

Tunnel Dewatering Pump Station and Enhanced Clarification Facility

GES provided mechanical, plumbing, fire protection, and process engineering for the new Tunnel Dewatering Pump Station (TDPS) and Enhanced Clarification Facility (ECF). GES is part of the PC Construction/CDM Smith Joint Venture, which brings together the industry-leading expertise in water treatment facility design and construction.

The $215 million design-build project will be constructed at the Blue Plains advanced wastewater treatment plant in Washington, DC. The TDPS-ECF are part of the larger DC Clean Rivers Project, mandated under a federal consent decree between the United States, 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-square-mile service area can overwhelm the system and treatment facilities with a diluted mix of rainwater and sewage, resulting in overflows into the Anacostia and Potomac rivers as well as Rock Creek.

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.

Major project components include the construction of a 250 mgd 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 TDPS will interface with the Blue Plains Tunnel and will include a building structure, building equipment and systems, utility services, odor control, pumping and other process equipment, a bridge crane, and piping, an electrical control building with equipment, and instrumentation and controls.

The ECF will be comprised of a building structure, building equipment and systems, utility services, odor control, process treatment structures, process equipment and piping, a low head pump station, and instrumentation and  controls, an electrical control building with equipment, process piping interconnections to existing Blue Plains Advanced Wastewater Treatment Plant.