Project Info

  • Client DC Water
  • Location Washington, DC
  • Cost $208 M
  • Size 78,500 sf

Biosolids Management Program, Main Process Train

Under a design/build contract, GES provided a variety of mechanical, plumbing and fire protection services for the HVAC modifications to the Solids Blending Building, design of the new 13,000 sf Solids Screening Building, 50,000 sf Pre-dewatering Building, a bridge connecting the two buildings, and a 15,500 sf Digester Gas Building. The plumbing design included the process plumbing for handling waste, solids and disposal to other facilities, and controls for all of the designed systems.

This project is the first of its kind in the United States, and the includes the largest Cambi plant in the world. The $208 M project has helped DC Water become more energy efficient, reduce its carbon footprint and lowered operating costs. The system provides about 1/3 of DC water’s plant saving about $10 M in electrical costs yearly. The plant used to create over 1,200 tons of “Class B” biosolids daily which was hauled about 75 miles by 60 truckloads daily. The new system creates half that amount and is a cleaner “Class A” biosolid, saving $ 2 M annually on treatment chemicals and $11 M annually in trucking expenses.


  • 2016 American Council of Engineering/Engineer Excellence Honor Award