Anaerobic digesters and biogas: wastewater treatment plants in Maryland
14 plants · 12% of the state · 249 MGD combined
Klarifi identifies 14 publicly owned wastewater treatment plants with anaerobic digesters and biogas in Maryland, 12% of the 118 plants in the state (249 MGD combined). The largest is Back River Wastewater Treatment Plant in Baltimore at 114.1 MGD.
Anaerobic digesters stabilise sludge in sealed heated tanks and produce biogas, visible from the air as digester silos and gas holders. Plants with digesters are typically above 5 MGD and are the buyers of mixing, heating, gas handling, cogeneration and dewatering equipment.
The largest plants with anaerobic digesters in Maryland
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Back River Wastewater Treatment Plant | Baltimore | 114.1 | MDL021555 | Dec 2030 | 32 |
| 2 | Patapsco Wastewater Treatment Plant | Baltimore | 49.01 | MDL021601 | Dec 2030 | 22 |
| 3 | Piscataway Swge Plnt | Accokeek | 19.79 | MDL021539 | Dec 2030 | 25 |
| 4 | Little Patuxent Water Reclamation Plant | Savage | 16.68 | MD0055174 | May 2031 | 8 |
| 5 | Sod Run Wastewater Treatment Plant | Perryman | 10.81 | MDL056545 | Dec 2030 | 0 |
| 6 | Annapolis WRF | Annapolis | 8.48 | MD0021814 | Jan 2030 | 6 |
| 7 | Ballenger-Mckinney WWTP | Frederick | 6.92 | MD0021822 | Dec 2030 | 1 |
| 8 | Parkway Wastewater Treatment Plant | Laurel | 6.35 | MDL021725 | Dec 2030 | 2 |
| 9 | Ocean City Wastewater Treatment Plant | Ocean City | 5.88 | MDL020044 | Dec 2030 | 2 |
| 10 | City Of Frederick Wastewater Treatment Plant-2012 | Frederick | 5.4 | MD0021610 | May 2031 | 23 |
| 11 | City Of Salisbury Wastewater Treatment Plant | Salisbury | 5.05 | MDL021571 | Dec 2030 | 83 |
| 12 | St. Michael'S WWTP | Saint Michaels | 0.29 | MD0023604 | Nov 2030 | 0 |
| 13 | Myersville WWTP | Myersville | 0.14 | MD0020699 | Sep 2030 | 0 |
| 14 | Friendsville WWTP | Friendsville | 0.02 | MD0021083 | 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 Maryland
Anaerobic digesters and biogas in other states
Anaerobic digesters and biogas 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.