Cobb County released the following information about a spill into the Chattahoochee River from the South Cobb Water Reclamation Facility in Mableton:

Cobb County Water System’s South Cobb Water Reclamation Facility released treated wastewater that did not fully meet the facility’s standards.

Cobb County Water System’s South Cobb Water Reclamation Facility is permitted by the Georgia Environmental Protection Division (EPD) to treat 40 million gallons of wastewater daily. Once treated, the water is released into the Chattahoochee River and routinely tested. EPD classifies the release of treated wastewater that doesn’t meet certain standards as a “spill.” This designation was determined by CCWS on Thursday, February 13, 2025, after receiving routine compliance sampling results. The effluent flow from the facility into the Chattahoochee River was 40.08 million gallons on February 12, 2025. The effluent was disinfected and will not impact drinking water supplies.

CCWS employees followed EPD protocols by promptly reporting the sampling results and are conducting daily water quality testing upstream and downstream of the effluent discharge location in the Chattahoochee River. Testing results indicate no impact to the river. No cleanup or remediation is required.

About the South Cobb Water Reclamation Facility

The South Cobb Water Reclamation Facility is located at 490 Lee Industrial Boulevard in Mableton. It serves portions of West Cobb, Austell, Powder Springs and Mableton.

The Cobb County website describes the history of the facility as follows:

The original South Cobb Water Reclamation Facility was constructed in 1963.  Situated on 18 acres in the 18th District on the Chattahoochee River, the plant was sized originally to treat 2 million gallons per day (mgd).  In 1973, the liquid process train was expanded to treat 8 mgd.  A second liquid process train was added in 1976, allowing the plant to process 24 mgd.  A sludge pelletization plant was installed for solids handling.  Improvements were made in 1989 to increase the plant capacity to 28 mgd.   A ferrous chloride feed facility was constructed in 1990.  

In 1992, the sludge gravity thickeners were converted to a dissolved air flotation thickener system.  1998, the two liquid process trains were combined into one, and plant capacity was increased to 40 mgd.  Belt presses replaced the pelletization system in the solids handling facility.  Improvements were made in 2004, with the addition of a bar screen and an odor control system at the headworks.  

A new chlorination/dechlorination system was constructed in 2005.   The plant was further upgraded in 2011 with the addition of a fifth clarifier, effluent filters, a reuse pumping station, and a plant recycle station.  In 2015, dewatering centrifuges replaced the belt presses.  In the chlorine system, sodium hypochlorite pumps and sodium bisulfite pumps were replaced.  The influent lift station was placed into service in 2016.  This pump station is 200 feet below ground and is the terminus of the 24-foot diameter South Cobb Tunnel.