COLMAR MANOR – Clean up of the imperiled Anacostia River is getting a boost from the latest in trash collection technology: a $350,000 giant garden rake.
The rake, officially a mechanical bar screen collector, was recently installed at the Colmar Manor pumping station. It’s expected to keep tons of debris from entering the river through the pumps, Prince George’s County officials said.
The Anacostia is one of the nation’s most environmentally threatened rivers. It was the fourth-most endangered river in 1993 and in the top-10 in 1994 on American Rivers’ annual report card. While it hasn’t made subsequent top lists from the conservation organization, the group still considers the Anacostia’s health tenuous.
Trash is one of the river’s chief threats. The filth collects at pumping stations after storms wash it down from urban areas. Until the rake was installed, that detritus was screened out by hand.
Now the rake pulls debris from storm water drain pipes up a vertical bar screen and dumps it into a bin. Bottles by far dominate the rubbish collected.
Hundreds of thousands of bottles float down the river every year, said Robert Boone, president of the Anacostia Watershed Society. Trash, he said, is the most underestimated problem threatening the river.
“It’s the least understood and still considerably serious,” he said.
Trash is a psychological toxin for the river, Boone said, explaining that the more trash people see in a river, the less they want to go by it.
“That’s what has happened with the Anacostia for many years. People see it and they never want to come by the river.”
Dry weather has meant there is little for the new rake to collect, but that will change with the first hard rain.
“I’ll guarantee you those pipes are still packed full of crud,” said Ed Womer, a capital projects inspector with Prince George’s County.
Trash builds up in the 60-inch pipe until a storm. When it does rain, a huge amount of runoff pushes the debris down to the pumping station at a very fast speed.
Prince George’s County Department of Public Works employees used to go down to the pumping stations during a storm to rake the trash away so the pipes wouldn’t get overrun with trash that would flow into the river, Womer said.
During a rainstorm, as much as 25,000 to 50,000 gallons of water is pumped at a controlled rate into the river. As much as 20,000 tons of trash flow into the river each year, the Maryland Department of the Environment estimates.
Two 13-foot-deep pits flank the pumping station at the end of the storm water pipes in both directions. Vertical bars about two inches apart stretch to the bottom of the pits, allowing water through and screening out trash.
About every 15 minutes, a rake drags the pit bottoms, pulling up the debris and depositing it in bins.
Since the rake began operating this July, there haven’t been any large rain storms to test it, said Dan Rybak, county capital projects section chief, so its productivity is unknown. He estimates five to 10 tons of trash will be captured a year.
Despite its unproven nature, county officials are hoping to install the devices at each of the eight other pumping stations along the river. The cost at other stations will be higher because of differences in the land and the pipes, Rybak said.
The best solution to the trash problem is still educating people, Rybak said.
“People are more environmentally sensitive now, but since more people are here, the volume of trash has increased,” he said. “People don’t really know what exactly happens to a Styrofoam cup that they throw out the window and how far it can travel.”