“Closed Circuit TV” (CCTV) 
Over the next 12 years, the City of Atlanta will inspect, repair
and where necessary, replace every foot of the 2,200 miles of
sanitary sewers. This unprecedented $1.2 billion project is
an integral part of the City’s comprehensive efforts to
meet and surpass all federal and state water quality standards.
The successful completion of the Clean Water Atlanta projects
will benefit Atlanta’s citizens and ratepayers, and
our neighbors downstream and throughout the region by providing
the infrastructure necessary to improve water quality and
sustain Atlanta’s economic vitality.
The SSES project is the first step in bringing Atlanta’s
aging sewer system up to world class/modern-day standards
and protecting Atlanta ratepayers’ quality of life by
eliminating Sanitary Sewer Overflows (SSOs). Through the efforts
of the SSES, approximately 60,000 manholes and 2,200 miles
of sanitary sewers will be inspected for cracks, collapses,
and blockages. After extensive investigation and documentation
of defects is completed, a rehabilitation plan will be developed,
identifying necessary sewer repairs and replacement. In severe
situations, immediate repair may be required.
One of the methods being used to survey the sewer lines is
the use of CCTV (closed circuit television) systems. This
cutting edge technology uses a television camera mounted on
a robotic device that is connected to a video monitor, a videocassette
recorder and other recording devices connected by a long electric
cable. The robotic system is placed directly into the sewer
through a manhole. Once inside the sewer line, the robotic
device can be operated by remote control located inside a
truck. The operator can examine the entire length of sewer
line between two manholes. The camera’s “pan and
tilt” capabilities allow the operator to move the camera
in all directions. Sonar or ultra sound systems can also be
used to examine the sewer below the waterline if sewage flow
is too high.
The CCTV system relays live footage from within the sewer
to a high-resolution monitor in a mobile survey unit. The
footage is also recorded on videotape. Since the operator
has full control of the robotic system, if a defect is detected,
the operator can stop the camera and investigate the defect
in more detail. With the camera’s pan and tilt capabilities,
service connections can also be located and documented. An
electronic footage counter is connected to the camera, enabling
the operator to note the exact location of problem spots.
The operator creates a structural and service condition report
as the live footage is viewed, documenting all defects and
noting the general condition of the sewer section.
Once the footage is returned to the office, it is reviewed
again to verify the operator’s initial field report
according to quality assurance standards. The sewer sections
are then given a grade from 1 to 5, with 5 representing the
most severe conditions (e.g., a sewer on the verge of total
collapse). The video footage is then transferred to CD-Rom
for easy storage and retrieval.
Benefits of CCTV
Cost: CCTV inspections require only a small work crew,
therefore making efficient use of man-hours. CCTV also allows
efficient examination of the sewer footage and specific information
on the exact condition and location of defects, enabling crews
to strategically target and implement repairs or maintenance.
Saves Time: Knowing the exact location of
defects and blockages enables crews to quickly repair and
rehabilitate problem areas.
Safety: Sewers can often contain toxic,
odorless gases. Though gas tests are always conducted prior
to crew members entering the sewer, there is still the possibility
that gases could seep in from unknown sources. Using CCTV
alleviates the risk to workers.
Efficiency: Through the CCTV system, operators
are able to review miles and miles of sewer footage on a specialized
computer program, which allows them to revisit problem areas
as often as needed without actually having to be in the field.
Documentation of sewer network topography and connections;
Generation of high-quality data for development of long-term
wastewater management plans.
Effective focusing of capital resources on sewer repair,
replacement, and rehabilitation.
For additional SSES Project information, please
call the CWA Hotline at 404.529.9211
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