Combined Sewer System Long Term Control Plan - DC Water

Responses to Comments
In the Draft LTCP, WASA has taken advantage of CSO reduction benefits of NMCrelated
measures. The two measures which have the most significant benefit are cleaning
of the Eastside Interceptor and replacement of the inflatable dams. These components
were assumed to be in place during the evaluation of alternatives. The benefits of these
elements are shown on page 6-2 of the LTCP. Implementation of these measures has
allowed for reduction in the size of capital facilities proposed in the Draft LTCP.
Regarding trash and floatables control, WASA will continue to:
Operate the Anacostia River Floatable Debris Program on the Anacostia River.
This is a skimmer boat program which removes floating debris on the river. Note
that this program removes debris from storm water and upstream Maryland
sources in addition to CSO sources.
Continue to operate the end of pipe netting system on CSO 018 on the Anacostia
River
Continue the increased frequency of catch basin cleaning recommended in the
NMC Summary Report.
Operate the screening facility at the Northeast Boundary Sewer and the bar racks
at the pumped overflows at the Main and ‘O’ Street Pumping Stations
Regarding a warning system to advise of overflows, WASA has proposed a warning light
system to advise the public in the Final LTCP.
3. COMMENTS ON ALTERNATIVES EVALUATION
3.1 Some commenters suggested moving toward decentralized treatment systems such as
composting toilets in lieu of centralized treatment systems (1,2). One commenter
suggested constructing holding tanks for sanitary wastewater at individual properties such
that wastewater could be held back during rain events so that overflows during rain
events would not contain sanitary sewage (8).
There are two basic options for the management of decentralized treatment systems:
operation by the utility such as WASA or operation by private individuals. Due to the
large number of properties, operation by a utility would not be cost effective or practical.
The large number required would be difficult to install, manage, maintain and operate.
Operation by individual properties would not be reliable in that a significant percentage
would likely be inoperable due to lack of maintenance. It is also unlikely that such a
system would be accepted by the populace due to the space requirements of such
systems, the need to enter private property to install them, and the disruption to private
properties.
\\Gh-wash\ENG 1160\LTCP\LTCP Final\App F-Resp to Com\Resp to Com.doc F-3 FINAL - July 2002