Washington Aqueduct chief Thomas Jacobus has again extended the public comment period on a plan to build a dewatering tower at the Dalecarlia Water Treatment Plant and haul away residuals by truck. The dewatering tower, a building about 80 feet high, would take sediment from the water treatment process and, using a centrifuge, squeeze out the water to create a topsoil-like byproduct.

The new deadline is July 6. The original June 6 deadline was first extended 15 days in response to appeals from local leaders. Last week, after further discussions with D.C. Council member Carol Schwartz, Jacobus issued another extension.

The Washington Aqueduct plans to stop dumping residuals into the Potomac River by 2009. Proposals to achieve that were outlined in a draft environmental impact statement published in April by the Army Corps of Engineers. The course of action recommended in the draft statement has met strong resistance from neighbors who are alarmed by the projected number of trucks -- 8 to 66 a day -- that could trundle down their streets if the plan were implemented.

Local political leaders, including Del. Eleanor Holmes Norton (D-D.C.), Maryland Democratic Senators Paul S. Sarbanes and Barbara A. Mikulski and Rep. Chris Van Hollen (D-Md.), previously asked for a delay in the publication of the environmental impact statement, because that would allow the public more time to study it before the public comment period closed.