Anaerobic digesters and biogas: wastewater treatment plants in Iowa
69 plants · 10% of the state · no reported flow
Klarifi identifies 69 publicly owned wastewater treatment plants with anaerobic digesters and biogas in Iowa, 10% of the 678 plants in the state (no reported flow). The largest is Mitchell County WW Pretreatment Plant in Osage at 0.03 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 | Mitchell County WW Pretreatment Plant | Osage | 0.03 | MO0030821 | Jun 2026 | 111 |
| 2 | Adair WWTP | Adair | — | IA0035416 | Jul 2029 | 4 |
| 3 | Algona City Of STP | Algona | — | IA0022055 | Feb 2028 | 13 |
| 4 | Anamosa WWTP | Anamosa | — | IA0025895 | Mar 2031 | 12 |
| 5 | Atlantic City Of STP | Atlantic | — | IA0029025 | Feb 2030 | 5 |
| 6 | Belmond City Of STP | Belmond | — | IA0041777 | Sep 2026 | 43 |
| 7 | Burlington, City Of (wwtp) | Burlington | — | IA0043079 | Jan 2027 | 4 |
| 8 | Carroll WWTP | Carroll | — | IA0021377 | Aug 2027 | 1 |
| 9 | Carson City Of STP | Carson | — | IA0042901 | Dec 2026 | 13 |
| 10 | Casey WWTP | Casey | — | IA0027197 | Aug 2029 | 28 |
| 11 | Cedar Falls City Of STP | Cedar Falls | — | IA0036633 | Dec 2029 | 0 |
| 12 | Centerville City Of STP (east) | Centerville | — | IA0027472 | May 2029 | 23 |
| 13 | Centerville City Of STP (west) | Centerville | — | IA0027464 | May 2029 | 33 |
| 14 | Cherokee WWTP | Cherokee | — | IA0059005 | Jan 2026 | 81 |
| 15 | City Of Boone Water Pollution Control | Boone | — | IA0058076 | Nov 2029 | 3 |
| 16 | City Of Muscatine Water & Resource Recovery Facility | Muscatine | — | IA0023434 | Mar 2030 | 20 |
| 17 | City Of Pella | Pella | — | IA0043869 | Mar 2027 | 0 |
| 18 | City Of Rinard WTP | Rinard | — | IA0033715 | Mar 2028 | 58 |
| 19 | City Of Shenandoah STP | Shenandoah | — | IA0032328 | Jan 2027 | 75 |
| 20 | City Of Sioux City STP | Sioux City | — | IA0043095 | Jan 2031 | 10 |
| 21 | Creston City Of STP | Creston | — | IA0035238 | Dec 2025 | 3 |
| 22 | Davenport Wastewater Treatment Plant | Davenport | — | IA0043052 | Jun 2026 | 0 |
| 23 | Decorah City Of STP | Decorah | — | IA0035220 | Oct 2027 | 3 |
| 24 | Denison Municipal Utilities WWTP | Denison | — | IA0023302 | Apr 2031 | 1 |
| 25 | Dewitt WWTP | Dewitt | — | IA0035271 | Sep 2029 | 5 |
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 September 11, 2026.