2008 Annual Report - DC Water

Sewer inspection and design activity
in FY 2008 included the following projects:
•yA detailed analysis of the sewer system in Northeast
Washington, using remote closed-circuit video
equipment, resulted in a plan to install new manholes
for better access, remove heavy root intrusion into the
sewer and repair cracks.
•yA similar detailed investigation was conducted in the
Northwest area, where cleaning and repairs were done
after an assessment of the storm sewer system.
•yAn evaluation is underway of a 10-inch sanitary sewer
that crosses Highway 295 near Barry Road, SE, to
improve flow conditions.
•yDesign work was completed for tide gate replacements
in order to begin construction in 2009. Tide gates are the
structures at various outfalls that prevent the river from
flowing into the combined sewer system during high tides.
•yNinety percent of the design work was completed
for the rehabilitation of the Blue Plains Influent Outfall
Sewers—the large-diameter sewers that receive
discharges from the major pumping stations and convey
flow to Blue Plains for treatment. The rehabilitated
sewers will be upgraded and in service by April 2011, as
required in an agreement with the federal government.
•yDesign work began in FY 2008 on Watts Branch
and Pope Branch sewer rehabilitation and stream
restoration programs. Both projects are examples of
government interagency cooperation in addressing
two key problems at the same time – the degradation
of the streams that these sewer lines cross and the
replacement of aging pipes.
Improved odor and corrosion control
technologies are priorities
The Potomac Interceptor conveys wastewater from Dulles
International Airport in Chantilly, VA, along the Potomac
River to the DC border and on to Blue Plains. The pipeline
serves the airport, Loudoun and Fairfax counties (VA), and
Washington Suburban Sanitary Commission (MD). This 50-
mile sewer has vents along the way to Blue Plains to allow
sewage to flow naturally. These vents can become the source
of odor; especially in warmer weather. DC WASA began
design and planning for a program to abate these odors in
1999 with six odor control buildings along the pipeline. The
$13 million program calls for the installation of a permanent
odor control system that includes a forced air/activated
carbon filter system. In FY 2008, building issues with the
National Park Service were resolved. Required zoning
changes in Northern Virginia are pending.
above: In addition to work on pipelines and pumping stations, sewer services includes the operations of skimmer boats,
which remove an average of 400 tons of floating trash and debris annually from the Anacostia and Potomac rivers.
dcwasa essential to Life. 20
2008 a n n u a l re p o r t