Anaerobic digesters and biogas: wastewater treatment plants in Iowa
71 plants · 10% of the state · 171 MGD reported by 67 plants
Klarifi identifies 71 publicly owned wastewater treatment plants with anaerobic digesters and biogas in Iowa, 10% of the 747 plants in the state (171 MGD reported by 67 plants). The largest is Water Pollution Control Facility in Cedar Rapids at 39.59 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 Iowa
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Water Pollution Control Facility | Cedar Rapids | 39.59 | IA0042641 | Aug 2030 | 15 |
| 2 | Davenport Wastewater Treatment Plant | Davenport | 25.36 | IA0043052 | Jun 2026 | 0 |
| 3 | City Of Sioux City STP | Sioux City | 14.01 | IA0043095 | Jan 2031 | 10 |
| 4 | Fort Dodge City Of STP | Fort Dodge | 11.42 | IA0044849 | Dec 2030 | 0 |
| 5 | Iowa City, City Of (south) STP | Iowa City | 8.98 | IA0070866 | Jul 2030 | 11 |
| 6 | Burlington, City Of (wwtp) | Burlington | 5.79 | IA0043079 | Jan 2027 | 4 |
| 7 | Mason WWTP | Mason City | 5.13 | IA0077305 | May 2029 | 6 |
| 8 | Cedar Falls City Of STP | Cedar Falls | 4.83 | IA0036633 | Dec 2029 | 0 |
| 9 | City Of Muscatine Water & Resource Recovery Facility | Muscatine | 3.89 | IA0023434 | Mar 2030 | 16 |
| 10 | Ottumwa City Of STP | Ottumwa | 3.24 | IA0058611 | Feb 2031 | 1 |
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 Iowa
Anaerobic digesters and biogas in other states
Anaerobic digesters and biogas in Iowa: 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: Anaerobic digester · Biosolids · Sludge dewatering · Centrate · Filter press · FOG · all terms