When Chattanooga was soaked with nearly two-and-a-half inches of rain in only a few hours Aug. 10, the city was able to divert more than 18 million gallons of stormwater runoff and sanitary sewage from parts of the city into three new giant storage tanks that have been erected on Moccasin Bend to prevent the deluge of sewer water from overwhelming the nearby sewage treatment plan
The tanks helped avoid the type of sewage overflow that in the past has dumped millions of gallons of untreated sanitary sewer overflow into the Tennessee River in violation of federal water regulations.
Chattanooga Mayor Tim Kelly celebrated the addition of the three, 10 million-gallon tanks Thursday as the latest milestone in the city’s $1.1 billion effort to address ongoing water pollution problems in handling the combined stormwater and sewage runoff in growing Hamilton County. Kelly said the city is about halfway through a 17-year program to make all of the improvements required under an agreement with the U.S. Environmental Protection Agency, but he said the new wet weather equalization station with its three large storage tanks and pumping network is a major milestone in upgrading the sewage system.
“We’re making tremendous progress, and this is a huge, huge landmark day,” Kelly said during a celebration in front of the tanks. “The Tennessee River is literally and figuratively the essence of our sustainability — the source of our drinking water, our scenic beauty and our recreation, as well as a major driver of our economic vitality. That’s why this facility is so important for our future.”
Mark Heinzer, interim director of the Moccasin Bend Environmental Campus, said the storage tanks allow sewer and stormwater to be diverted and stored in the tanks until the rainstorms are over. The excess sewer water is then released from the tanks to the nearby Moccasin Bend Sewage Treatment Plant to clean the contaminated water before it is released downstream in the Tennessee River. Moccasin Bend can treat up to 230 million gallons of water a day, but when heavy rains overwhelm the city’s stormwater system and overflow into sewage systems, Moccasin Bend is not always able to treat all of the incoming sewage.