Oxidation ditches: wastewater treatment plants in Ohio
112 plants · 13% of the state · 155 MGD reported by 109 plants
Klarifi identifies 112 publicly owned wastewater treatment plants with oxidation ditches in Ohio, 13% of the 843 plants in the state (155 MGD reported by 109 plants). The largest is North Regional Wastewater Treatment Plan (0857143037) in Dayton at 11.24 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 Ohio
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | North Regional Wastewater Treatment Plan (0857143037) | Dayton | 11.24 | OH0049646 | Feb 2027 | 49 |
| 2 | Upper Mill Creek Water Reclamation Facil | West Chester | 10.8 | OH0072087 | Dec 2023 | 37 |
| 3 | Beavercreek WRRF | Dayton | 9.73 | OH0025381 | Nov 2030 | 47 |
| 4 | Findlay WPCF | Findlay | 9.51 | OH0025135 | Oct 2029 | 1 |
| 5 | Lower East Fork Regional WWTP | Milford | 7.83 | OH0049379 | Oct 2026 | 4 |
| 6 | Mason WWTP No 2 | Mason | 7.31 | OH0020494 | May 2026 | 0 |
| 7 | French Creek WWTP | North Ridgeville | 6.82 | OH0044512 | Oct 2027 | 14 |
| 8 | Niles WWTP | Niles | 5.01 | OH0026743 | Sep 2028 | 9 |
| 9 | Fairborn Water Reclamation Center | Huber Hts | 4.64 | OH0025062 | Nov 2026 | 0 |
| 10 | Piqua WWTP | Piqua | 3.72 | OH0027049 | Aug 2027 | 3 |
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 Ohio
Oxidation ditches in other states
Oxidation ditches in Ohio: 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 · POTW · MGD · all terms