Floating TrashTrap on the Anacostia River in Washington DC

Project Profile: Anacostia Watershed, the Takoma Branch had high levels of pollution. About 20,000 tons of trash were flowing into Anacostia annually according data collected by National Oceanic. Cleanup and restoration efforts for the Anacostia watershed began nearly two decades ago. Formal cooperation between government agencies came in 1987 with the signing of the landmark Anacostia Watershed Agreement and the formation of the Anacostia Watershed Restoration Committee (AWRC). One of their main objectives was to “promote the greater introduction and use of effective trash reduction technologies and approaches.” Which included the investigation of different Best Available Technologies (BATs). A floating Netting TrashTrap System was selected for this project because it provided a simple, cost effective, and direct solution to the problem.

Challenges: The water flow through this outfall was too high (more than 10 feet per second) to install a standard in-line or end-of pipe system. Because of that, a floating system was chosen for this project. The system was placed into the receiving body of water in such a way as to dissipate the velocity before it enters the net. A floating gangplank (walkway) was also added to enable people to access the Floating Netting TrashTrap from the shore.

Solutions: A Netting TrashTrap System containing two ½” mesh nets was designed and installed to capture trash that washes off the streets around the Washington Naval Yard into catch basins, which, in turn, feed into the sanitary sewer. The system operates unattended and utilizes the energy of stormwater flow to drive trash into the nets. Upon reaching its capacity of approximately 1 ton, the nets are disposed of and replaced with new ones. A crane is used to lift the full bags, into a dump truck, which then hauls them to a local landfill.