Oxidation ditches: wastewater treatment plants in Tennessee
40 plants · 16% of the state · 80 MGD reported by 37 plants
Klarifi identifies 40 publicly owned wastewater treatment plants with oxidation ditches in Tennessee, 16% of the 243 plants in the state (80 MGD reported by 37 plants). The largest is City Of Cookeville Department Of Water Quality Control (wwtp) in Cookeville at 10.75 MGD.
Oxidation ditches are ring-shaped activated sludge reactors with long retention times, common at plants between 0.5 and 10 MGD. They are recognisable from the air by their looped channels and rely on surface aerators or brush rotors, which are frequent replacement and energy-efficiency projects.
The largest oxidation ditch plants in Tennessee
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | City Of Cookeville Department Of Water Quality Control (wwtp) | Cookeville | 10.75 | TN0024198 | Jun 2027 | 27 |
| 2 | City Of Franklin Wastewater Treatment Plant | Franklin | 9.77 | TN0028827 | Dec 2026 | 44 |
| 3 | Hallsdale-Powell U.D.-Melton Hill Lk | Knoxville | 6.35 | TN0078905 | Sep 2028 | 44 |
| 4 | Harpeth Valley Utility District STP | Nashville | 5.88 | TN0074748 | Feb 2030 | 4 |
| 5 | Sevierville (mccroskey Island) STP | Sevierville | 4.74 | TN0063959 | Apr 2030 | 115 |
| 6 | City Of Spring Hill STP | Spring Hill | 3.83 | TN0075868 | Dec 2028 | 41 |
| 7 | Collierville Northwest STP | Collierville | 3.64 | TN0078841 | Jan 2028 | 4 |
| 8 | Knob Creek Waste Water Plant | Johnson City | 3.26 | TN0024236 | Sep 2026 | 15 |
| 9 | Shelbyville Wastewater Treatment Plant | Shelbyville | 3.22 | TN0024180 | Jan 2029 | 21 |
| 10 | Denzil Bowman Wastewater Treatment Plant (greeneville Stp) | Greeneville | 3.1 | TN0021229 | Oct 2030 | 30 |
Contacts and project signals for every plant on this list
Klarifi adds verified decision-maker contacts, permit limits, discharge monitoring data and the capital projects planned in each city, filterable by technology, size and compliance record.
Other technologies in Tennessee
Oxidation ditches in other states
Oxidation ditches in Tennessee: questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed October 26, 2026.
Wastewater terms: Oxidation ditch · Activated sludge · Biological nutrient removal · Equalization tank · Centrate · all terms