Southport Advanced Wastewater Treatment Plant Capacity Expansion

The Southport Advanced Wastewater Treatment Plant in Indianapolis, Indiana is one of two large wastewater treatment plants owned and operated by Citizens Energy Group that serves the Indianapolis metropolitan area. In 2006, the federal government mandated that approximately 30 combined sewer overflow control measures be implemented by the year 2025 to reduce raw sewage overflows into Indianapolis area waterways.

Four CMs were identified at the Southport Plant to increase peak low capacity from 150 MGD to 250 MGD by December 2017, including Headworks, Primary Clarifier Expansion, Secondary Treatment System Expansion, and Wet Weather Disinfection.

In 2011, Citizens purchased the Indianapolis community’s water and wastewater treatment utilities from the City of Indianapolis. Citizens realized the opportunity to consolidate the four CMs required bundling the Southport Plant into one project to achieve efficiencies in design and construction. As lead designer, HNTB managed the design of the plant upgrades. The HNTB-led team’s design exceeded the mandated capacity expansion requirements and additional opportunities to increase low capacity were realized. Once all  implements are made, the wastewater system will be able to divert 3.5 billion gallons of sewerage that is currently polluting local waterways.