By Martin Weil
Washington Post Staff Writer
Tuesday, October 23, 2007
Raw sewage is flowing into the Anacostia River from a leak in a major sewer line that carries untreated waste from a pumping station in Southeast Washington, D.C. Water and Sewer Authority officials said last night.
About 5 million gallons of sewage go through the pumping station each day. The size of the leak, which was discovered yesterday, was not immediately known, officials said. It is "not a gusher," said John Dunn, WASA's chief engineer and deputy general manager. But he said that "to my knowledge, it's the first time that we've had a break in one of these" main sewage transmission lines.
The line, estimated to be about four feet in diameter, feeds into one of three larger lines -- each about five feet in diameter -- that carry sewage across the Anacostia River on the way to the Blue Plains treatment plant.
The cause of the leak was not immediately known. It was discovered when workers repairing part of the riverbank spotted water churning nearby. Tests showed that sewage probably was flowing out of a buried line somewhere between the O Street pumping station and the riverbank.
Dunn said that the leak near the O Street station does not pose a threat to public health, noting that more untreated sewage flows into the river on rainy days, when runoff overwhelms the city's sewer system and treatment capacity.
As a first step in coping with the leak, officials said they will try to bypass the leaking pipe by connecting the O Street station with the city's main pumping station, which has a larger capacity.
The work might begin today and could be completed in about 24 hours, Dunn said. Repairing the leaking pipe was expected to take longer, he said.
Most of the sewage generated in parts of the District north and west of the Anacostia River passes through one of the two pumping stations. Of the two, the O Street station carries a considerably smaller volume.
Dunn said the O Street pumping station was designed to handle about 45 million gallons a day, but because of dry conditions, it has been pumping about 5 million gallons a day, about 11 percent of capacity.
He said the treatment plant at Blue Plains has been processing about 300 million gallons a day, so that less than 2 percent of its volume comes from O Street.
He said that the U.S. Environmental Protection Agency was told of the city's plan and that EPA officials "seem to think it's a reasonable approach."
Dunn said that the leak had produced no discoloration of the water in the Anacostia, which flows into the Potomac River near Hains Point.
"We have our fingers crossed it's not leaking much," he said of the sewer line.
He said determination of the leak's size would not be possible until workers dig down to the reinforced-concrete line.
He said it was about 19 feet underground and about seven feet lower than the surface of the river.