Southport Advanced Wastewater Treatment Plant
The city of Indianapolis planned to install a deep tunnel system under the city as a result of negotiations with the EPA to significantly decrease combined sewer overflows. Once in operation, the tunnel flows, estimated at 90 MGD, were to be pumped to the Southport Advanced Wastewater Treatment Plant, which did not have the capacity to treat these additional flows. Therefore, the City moved forward with a plan to expand the plant from its current design capacity of 150 MGD to 250 MGD. American Structurepoint was part of a team charged with analyzing the existing plant condition and capacity and identifying and evaluating options for upgrading each of the processes in the plant, including screening and pumping, grit removal, primary clarification, secondary treatment, and disinfection.
The study included new versus rehabilitated screens and pumps, vortex or aerated grit removal versus primary sludge degritting, and new versus hydraulically upgraded primary and secondary treatment. The plant employed chlorination/dechlorination for disinfection, but had an ozone production system on site purchased with the intent of ozone treatment for disinfection and use in the oxygen nitrification system. It was being used for neither operation. A cost and benefit analysis was performed to determine if it was more beneficial for the plant to continue with chlorination/dechlorination or employ the ozone system for disinfection.