Oxidation ditches: wastewater treatment plants in Maryland
16 plants · 14% of the state · 21 MGD combined
Klarifi identifies 16 publicly owned wastewater treatment plants with oxidation ditches in Maryland, 14% of the 118 plants in the state (21 MGD combined). The largest is City Of Frederick Wastewater Treatment Plant-2012 in Frederick at 5.4 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 Maryland
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | City Of Frederick Wastewater Treatment Plant-2012 | Frederick | 5.4 | MD0021610 | May 2031 | 23 |
| 2 | Broadneck Water Reclamation Facility | Annapolis | 3.68 | MDL021644 | Dec 2030 | 106 |
| 3 | Easton WWTP | Easton | 2.02 | MDL020273 | Dec 2030 | 2 |
| 4 | Freedom District WWTP | Sykesville | 1.97 | MD0021512 | Oct 2029 | 32 |
| 5 | Conococheague WWTP | Williamsport | 1.84 | MD0063509 | May 2031 | 0 |
| 6 | The City Of Bowie (ssos) | Bowie | 1.4 | MDL021628 | Dec 2030 | 8 |
| 7 | Northeast River Advanced WWTP | Charlestown | 1.25 | MDL052027 | Dec 2030 | 38 |
| 8 | George'S Creek WWTP | Westernport | 0.77 | MD0060071 | May 2026 | 0 |
| 9 | Piney Orchard WWTP | Odenton | 0.52 | MDL059145 | Dec 2030 | 6 |
| 10 | Pocomoke City Wastewater Treatment Facility | Pocomoke City | 0.52 | MD0022551 | May 2028 | 0 |
| 11 | Hampstead WWTP | Hampstead | 0.48 | MD0022446 | Aug 2030 | 25 |
| 12 | St. Michael'S WWTP | Saint Michaels | 0.29 | MD0023604 | Nov 2030 | 0 |
| 13 | Rock Hall WWTP | Rock Hall | 0.22 | MD0020303 | Jul 2029 | 7 |
| 14 | Rising Sun Town Of WWTP | Rising Sun | 0.2 | MD0020265 | Apr 2028 | 22 |
| 15 | Clear Spring WWTP | Clear Spring | 0.11 | MD0053325 | Jul 2025 | 0 |
| 16 | Antietam WWTP | Sharpsburg | 0.11 | MD0062308 | Jan 2030 | 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 Maryland
Oxidation ditches in other states
Oxidation ditches in Maryland: 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 September 11, 2026.