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Citywide Orthophosphate Treatment Starts in August Public Meetings Planned

Release Date: 8/5/2004
Contact Information: David Sternberg, EPA, 215-814-5548, Karen Dewitt, D.C. WASA 202-787-2200, Tom Jacobus, Washington Aqueduct 202-764-2753

WASHINGTON – The U. S. Environmental Protection Agency has approved the system-wide use of orthophosphate as the next step in preventing lead from leaching into Washington, D.C. drinking water.

The Washington Aqueduct expects to feed the orthophosphate at both treatment plants, Dalecarlia and McMillan, for system-wide distribution on or about August 23. It is expected that it will take six months or longer for lead levels to decrease after implementation of the orthophosphate treatment.

The decision comes two months after EPA and technical experts from the Washington Aqueduct and D.C. WASA began adding orthophosphate to a limited part of northwest Washington’s water supply to eliminate lead corrosion.

Frequent sampling since the orthophosphate trial began in June has found no significant increase in bacteria, or occurrence of reddish brown water due to dissolved iron in the application area.

“It will take six months to a year to be sure that a protective film is building up in the pipes to block further lead corrosion. But as we are not seeing undesirable side effects from the partial application, the Technical Expert Working Group recommends applying the orthophosphate solution systemwide,” said Rick Rogers, drinking water chief for EPA’s mid-Atlantic region

Orthophosphate is a tasteless, odorless, food-grade additive used by many water systems nationwide to control corrosion in metal pipes. It works by building up a thin film of insoluble mineral scale in lead, copper and iron pipes and fixtures. Inside the pipe, the film serves as a liner that keeps corrosive elements in water from dissolving some of the metal.

System-wide application is the next step in the plan to eliminate lead corrosion in the million customer D.C. water system, which also serves Arlington County and Falls Church, Va.

Residents should continue to follow the flushing guidance until the new treatment can be shown to reduce the leaching of lead.

The Technical Expert Working Group was formed in February to coordinate research and recommend treatment strategies to reduce elevated lead levels in district water and includes representatives of the Washington Aqueduct (U.S. Army Corps of Engineers), EPA, D.C. WASA, the D.C. Department of Health, the Centers for Disease Control and Prevention, and the Virginia communities.

The group will hold two public meetings to explain the treatment plan. The first will be held on August 19, at Congress Heights United Methodist Church (Basement) 421 Alabama Ave., S.E. It will include an open house from 6:00 to 7:30 p.m. and a formal presentation followed by a question and answer session from 7:30 to 8:30 p.m.

The second public meeting will be held Tuesday, August 24, at the Martin Luther King Library (Meeting Room A-5) 901 G. Street, N.W. It will also include an open house from 6:30 to 7:30 p.m. and a formal presentation followed by a question and answer session from 7:30 to 8:30 p.m.

The meetings are part of a citywide outreach campaign to inform residents about the new water treatment and what they can expect. Before the Washington Aqueduct feeds orthophosphate into the District’s water distribution system, D.C. WASA is scheduled to send a letter to all D.C. residents providing details about the citywide application. D.C. WASA has indicated that they will continue to update D.C. residents on the progress of the treatment and provide tips on what residents can do to counter the potential temporary side effect of the treatment - reddish brown water.

DC WASA and the Washington Aqueduct are preparing for the new treatment by developing additional monitoring plans and taking actions to ensure prompt responses to any customer concerns that may be reported. A citywide flushing program will also be underway at the time of treatment to minimize problems.