Tunnel Dewatering Pump Station and Enhanced Clarification Facility

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Two key components of DC Water’s Nitrogen Removal/Wet-Weather Program include the Tunnel Dewatering Pump Station (TDPS) and Enhanced Clarification Facility (ECF). This project starts where the massive DC Clean Rivers Project tunnels end at Blue Plains. The Tunnel Dewatering Pump Station (TDPS) and Enhanced Clarification Facility (ECF) began accepting the millions of gallons of combined sewage that previously flowed into the District's waterways during heavy rainstorms. Principal components include complete treatment for a rate of up to 555 million gallons per day (mgd) for the first four hours during a wet weather event, and 511 mgd thereafter, a 225 mgd ECF constructed to treat captured wet-weather flows from the tunnel in addition to providing a higher level of treatment, and a new Tunnel Dewatering Pump Station equal to the capacity of the ECF with sufficient capacity to dewater the tunnel system.