Central WWTP Capacity Improvements and CSO Reduction
The Central Wastewater Treatment Plant (CWWTP) Capacity Improvements and CSO Reduction project will reduce the overflow frequency and volume from the Kerrigan CSO by increasing both the wet weather treatment capacity of the CWWTP and the overall capacity of the Central Pumping Station. The project will also add on-site CSO storage and equalization to assist in managing the dramatic flow rate increases from the combined sewer system during intense rainfall events.
The CWWTP, the largest treatment plant in Nashville, is located in the Germantown and Salemtown area near downtown and was originally constructed in 1958. It has previously had four major expansions. Peak plant capacity is currently 330 million gallons per day (mgd), and the project’s planned improvements will expand it to over 400 MGD. The $400M project is being delivered through a Construction Manager at Risk (CMAR) approach.
Improvements include, but are not limited to: Central Pump Station upgrades, new switchgear building, new 440 mgd headworks facility, large diameter conveyance piping, primary settling tank improvements, Intermediate Pump Station upgrades, conversion to fine bubble aeration, new blowers, Return Activated Sludge (RAS) system improvements, conversion of existing chlorine contact tanks to new ultraviolet disinfection facility, plant water system improvements, biosolids facility improvements, new waste gas flare, excess flow treatment unit modifications, civil and landscaping improvements, and primary power system improvements.
Project Timeline
| Phase | Start | Finish |
|---|---|---|
| Design | September 2015 | May 2020 |
| Permitting/Bid/Award | August 2016 | September 2020 |
| Construction | July 2020 | August 2024 |
Additional Information
- Project Summary
- Executive Summary
- Central WWTP Optimization Study - 2014
- CWWTP Biosolids Facility Assessment - October 2014
- CWWTP Electrical Equipment Condition List - December 2014
- CWWTP Electrical System Assessment - January 2015
- CWWTP Post May 2010 Flood Report - May 2014
- Brown and Caldwell Scope of Work
- Hazen and Sawyer Scope of Work
- Central WWTP Optimization Basis of Design Report - 2016
- Central WWTP - Final Basis of Design Report Update - 2018
- Virtual Open House - August 2020
- Blasting FAQs - Central Upgrade Project
Project Photos
Initial demolition site work for headworks facility, Spring/Summer 2020
Construction continues on headworks facility, Updated December 1, 2021