“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 more information, please contact the Project Hotline at 404.546.3200.