Collection System

Discover Chattanooga's wastewater collection system, its history, maintenance, and divisions ensuring efficient wastewater management and environmental protection.

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Wastewater Maintenance Overview

The wastewater collection system conveys used water from residential and commercial sources to the Moccasin Bend Wastewater Treatment Plant. The collection system consists of gravity flow sewer lines, pressurized force mains, manholes, and pumping facilities. Constant maintenance of the collection system is necessary to ensure proper operation.

Collection System Components

  • Gravity Flow Sewer Lines
  • Pressurized Force Mains
  • Manholes
  • Pumping Facilities

The wastewater system contains approximately 1,263 miles of sewer lines ranging in size from six inches to 84 inches in diameter, and 26,000 manholes.

Maintenance Activities

Collection system maintenance personnel are responsible for:

  • Excavating and repairing existing lines
  • Constructing new lines
  • Using television cameras to inspect lines daily
  • Cleaning lines

History of the Collection System

Early Development (1890s)

Chattanooga's sewer "collection system" refers to the network of pipes, manholes, and pump stations required to transport wastewater from homes, businesses, and industries to the Moccasin Bend Wastewater Treatment Plant. The first sewer pipes in Chattanooga were built around 1890. Large brick pipes were constructed to carry both stormwater and sanitary sewage from the downtown area directly to the river, without any treatment.

Expansion and Diversion (1950s)

As Chattanooga grew, more sewers were constructed. Outside the downtown area, sewers were built to carry only sewage, with separate lines for stormwater. The sewage pipes were often made of vitrified clay and later of concrete. In the 1950s, pipes were constructed to divert dry weather sewage away from the river, carrying it to Moccasin Bend, which later became the wastewater treatment plant site. During rainstorms, combined sewage and stormwater would overflow and continue to flow to the river.

Treatment Plant Construction (1961-1970)

After the wastewater treatment plant was constructed and improved in 1961 and 1970, large pipes were generally made of concrete and smaller pipes of plastic. Concrete manholes replaced the original brick structures. More pump stations were constructed to pump the flow over hills or where sewage pipes would be too deep.

Major Sewer Expansion (1980s)

After many outlying areas were annexed in the 1980s, Chattanooga began another major sewer expansion program.

Compliance with Federal Regulations (1990s)

In the early 1990s, new federal regulations required cities with "combined" sewers to manage the combined flow in approved ways. Between 1990 and 2000, Chattanooga constructed Combined Sewer Overflow (CSO) Facilities to capture this flow and provide holding areas and primary treatment. There are eight CSO facilities in operation.