The city of Chattanooga says its new wet-weather equalization station, which consists of three storage tanks that can hold up to 30 million gallons of wastewater, has prevented untreated wastewater from overflowing into the Tennessee River during heavy rains since it became fully operational in June.
The storage tanks are among a number of improvements Chattanooga has constructed in order to end the discharge of untreated sewage into the Tennessee River, says Mark Heinzer, interim director of the Moccasin Bend Environmental Campus.
“When Chattanooga was hit with a 10-year rain event that flooded streets, parking lots and buildings Aug. 10, one very important thing did not happen – no untreated wastewater overflowed into the Tennessee River, thanks to the city’s new wet weather equalization station.
“Instead, 18 million gallons of wastewater and rainwater overflow was pumped into tanks and later released into our treatment plant for purification.”
In addition to the completion of the equalization station, the Department of Public Works has made progress in repairing and rehabilitating other parts of the city’s wastewater system since entering into a consent decree with the federal government in 2013.
These include rehabilitating 12 pump stations (with four more slated for 2023), completing 12 capital projects to improve the Moccasin Bend Wastewater Treatment Plant, inspecting and evaluating 284 miles of pipe and rehabilitating 73 miles of pipe (about 25% of the system), rehabilitating over 2,000 manholes and cleaning approximately 1 million feet of pipe throughout the city annually.
The consent decree is an agreement between the federal government and the city meant to correct a violation of federal law to avoid litigation.
In this case, Chattanooga’s old and inadequate sewer system, which combined both sewage and the city’s often torrential rainfall into one system, was repeatedly overflowing during heavy rains, causing nearly 100 million gallons of untreated wastewater to flow into the Tennessee River every year.
The resulting contamination of the Tennessee River violated the federal Clean Water Act. In response, the city entered into a consent decree with the Tennessee Department of Environment and Conservation and the EPA in 2013 to start rehabilitating and renewing its wastewater system.
Chattanooga is about halfway through its $1.1 billion, 17-year commitment under the consent decree.
Source: City of Chattanooga