WASHINGTON — Repairs on a pipe rupture that has sent sewage flowing into the Potomac River northwest of Washington, D.C., will take weeks more to repair because of an unexpected blockage, according to the local water authority.
In a release posted on its website Thursday, DC Water, which operates the sewer system, said a video inspection of the pipeline revealed the blockage inside the collapsed sewer line ''is far more significant'' than originally thought. It said it discovered a large rock dam about 30 feet (9 meters) from the breach in the sewage line, which requires treatment before the current spill can be addressed.
It will take an estimated 4 to 6 weeks longer than initially anticipated to get a system in place, including bringing in bigger equipment, to address the problem and begin removing the large rocks and boulders inside the sewer line, DC Water said.
The 72-inch (183-centimeter) pipeline, called the Potomac Interceptor, collapsed Jan. 19, shooting sewage out of the ground and into the river just north of Washington in Montgomery County, Maryland. In its initial announcement, DC Water said the leak was causing an estimated 40 million gallons (about 150 million liters) a day of wastewater — enough to fill about 66 Olympic-size swimming pools— to escape into the Potomac River.
DC Water said it knew the pipe, first installed in the 1960s, was deteriorating, and rehabilitation work on a section about a quarter-mile (400 meters) from the break began in September and was recently completed.
The agency has been assessing water quality for bacteria contamination and said that while E. Coli levels are well beyond safe levels at the site of the leak, the levels are within safe levels at other sampling sites downstream into Washington.
The Washington Department of Energy and Environment said in an emailed statement that it was continuing to advise that the public and their pets avoid contact with the water until the situation is fully resolved and bacteria levels are reported as safe. ''DC drinking water remains safe for everyone to drink and use.''
Sherri Lewis, a spokesperson for DC Water, said the overflow was initially 40 million gallons a day and stayed at that level for five days. Since then there have been limited overflows when pumps are taken out of service because of clogs caused by items such as wipes and grease that reduce pumping capacity.
