Problem: Trash pollution impairs the Anacostia River in Washington, D.C.
Solution: Installation of a floating litter-collecting device on a tributary to the river and engaging the community in removal of the litter from the waterway.
The Anacostia River, coursing through Washington, D.C., has been cited as the most polluted river in the United States, with 18,000 Mg/yr (20,000 ton/yr) of trash entering the waterway. While a variety of pollutants affect its water quality, trash is the most visible, negatively affecting aesthetics, habitat, and environmental functions of the river, according to John Wasiutynski, environmental protection specialist for the District Department of the Environment (DDOE).
Instituting a Plan
To respond to this blight, DDOE instituted the Anacostia Trash Reduction Plan, which incorporates remediation, education, and interagency cooperation activities. The plan is a part of the District of Columbia’s “green” agenda, with the goal of creating a swimmable and fishable Anacostia by 2032.
For the initiative, the department is testing a variety of technologies for effective and efficient trash reduction. The agency is experimenting with curb-inlet screens and retrofitting catch basins and other types of in-stream traps in the separated sewer systems to clean the Anacostia.
DDOE and the Anacostia Riverkeeper (Washington, D.C.) discovered the Bandalong Litter Trap and decided to test the system, with DDOE providing support and the Anacostia Riverkeeper taking the role of project leader. The Anacostia Riverkeeper awarded a grant to the Earth Conservation Corps (ECC; Washington, D.C.) for the purchase, installation, and maintenance of the system and catch-basin inserts and curb-inlet grates, installed as additional measures to remove pollution in the area. The grant is a part of a 2-year cost analysis and effectiveness comparison.
Removing the litter from the trap, and, therefore, placement of the trap, was an important consideration for DDOE and ECC. ECC members manually remove the litter during low tide as part of their contract to maintain the trap. DDOE will take over maintenance of the trap at the end of the contract.
The trap was installed in April 2009 in a hot spot for trash in the Watts Branch tributary, which flows through some of the most urban and impoverished sections of Washington, D.C.
Customization and Operation of The Litter Trap
DDOE worked closely with Storm Water Systems (Cleveland, Ga.), manufacturer of the trap, to customize the trap to span the 12-m-wide (40-ft-wide) tributary. The system is constructed of aluminum and high-density polyethylene booms that float on the surface of the tributary. The booms form a large V-shape that directs floating trash to a rectangular trap for storage until the unit is cleaned.
Poles at the front of each boom are attached to an overpass, allowing the device to remain in place and still rise and descend with the water levels. Cables tethered to the ground also assist in keeping the system stable.
The trap allows fish and water to pass safely under the trap unobstructed while catching trash that floats on the surface of the water. The forward booms use the water current to guide floating litter and debris into the rectangular trap, where a gate secures it even during tidal changes or high wind.
In the future, existing public works equipment may be employed to empty the trap. For example, truck-mounted jib cranes could lift out removable aluminum baskets, or a vacuum truck’s extended boom may be lowered into the trap. For outreach, ECC utilizes local youth volunteers to help clean the litter trap and spread the public service message to dispose of trash properly.
The system quietly collects litter throughout the year and has a life expectancy of more than 20 years. It requires little regular maintenance, which includes inspection of anchor cables for obstructions after extreme rainfall events and servicing the grease fittings on the gate once a year. Because of the unit’s life expectancy, the capital expenditure is spread over many years with low maintenance costs and no energy requirements.
“In our program to test available litter collection tools, the [trap] has performed well to this point and at this site,” Wasiutynski said. Within the first 6 months of the Bandalong installation, more than 2268 kg (5000 lb) of trash have been removed from the Anacostia River, consisting of plastic bottles, balls, and bags, as well as several tires and a shopping cart, according to an ECC report.
Gary Hopkins, president of Storm Water Systems, said there is a direct correlation between rainfall and the amount of trash collected. “When we compare collection reports from the ECC with rainfall in the area, the data shows what is expected — when the litter is on the move, the [trap] is doing its work, collecting trash and preventing it from moving downstream,” he said. Some submerged trash, such as clothing, will bypass the trap.
The system also serves as an educational tool; the floating trap holds a sign with an antilittering message from the participating community organizations to raise public awareness of the issue. It also has the potential to be used for water quality testing and water filtering media. To date, 192 Bandalong Litter Traps are in use in eight countries internationally, including Australia, Indonesia, Singapore, and the Philippines.
©2010 Water Environment Federation. All rights reserved.