Anaerobic digesters and biogas: wastewater treatment plants in Illinois
93 plants · 15% of the state · 371 MGD reported by 86 plants
Klarifi identifies 93 publicly owned wastewater treatment plants with anaerobic digesters and biogas in Illinois, 15% of the 641 plants in the state (371 MGD reported by 86 plants). The largest is MWRDGC Terrence J O'Brien Water Reclamation Plant in Skokie at 170 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 Illinois
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | MWRDGC Terrence J O'Brien Water Reclamation Plant | Skokie | 170 | IL0028088 | Jul 2022 | 18 |
| 2 | Sanitary District Of Decatur | Decatur | 26.53 | ILL028321 | Dec 2030 | 1 |
| 3 | Springbrook Water Reclamation Center | Naperville | 17.26 | ILL034061 | Dec 2030 | 0 |
| 4 | Bloomington Normal WRD -West STP | Bloomington | 10.71 | ILL027731 | Dec 2030 | 0 |
| 5 | Fox River Water Reclamation Dist | Elgin | 10 | ILL028657 | Dec 2030 | 51 |
| 6 | Elmhurst Stp, City Of | Elmhurst | 7.92 | ILL028746 | Dec 2030 | 8 |
| 7 | Spring Creek STP | Springfield | 7.59 | ILL021989 | Dec 2030 | 28 |
| 8 | Glenbard Wastewater Authority | Glen Ellyn | 7.04 | ILL021547 | Dec 2030 | 27 |
| 9 | Joliet West Stp, City Of | Joliet | 6.67 | ILL033553 | Dec 2030 | 0 |
| 10 | Downers Grove Sanitary District | Downers Grove | 6.39 | ILL028380 | Dec 2030 | 5 |
| 11 | Urbana & Champaign Sd | Urbana | 6.2 | ILL031500 | Dec 2030 | 2 |
| 12 | Woodridge-Greene Valley WWTP | Woodridge | 6.1 | ILL031844 | Dec 2030 | 2 |
| 13 | Romeoville Wastewater Treatment Facility | Romeoville | 4.81 | ILL048526 | Dec 2030 | 0 |
| 14 | Wheaton Sanitary District WWTF | Wheaton | 4.5 | ILL031739 | Dec 2030 | 7 |
| 15 | Plainfield North Stp, Village Of | Plainfield | 4.34 | ILL074373 | Dec 2030 | 0 |
| 16 | Scwrd Sugar Creek WWTP | Springfield | 3.95 | ILL021971 | Dec 2030 | 9 |
| 17 | East Moline Wastewater | East Moline | 3.74 | IL0028550 | Mar 2031 | 2 |
| 18 | Frankfort, Village Of | Frankfort | 3.32 | ILL072192 | Dec 2030 | 7 |
| 19 | Galesburg Sanitary District STP | Galesburg | 3.22 | ILL023141 | Dec 2030 | 6 |
| 20 | Fox River Water Reclamation Di | Elgin | 3.21 | ILL035891 | Dec 2030 | 0 |
| 21 | Belleville Wastewater Treatment Facility | Belleville | 3 | ILL021873 | Dec 2030 | 2 |
| 22 | Moline South Treatment Plant | Moline | 2.72 | ILL029939 | Dec 2030 | 3 |
| 23 | Collinsville Wastewater Treatment Plant | Collinsville | 2.59 | ILL028215 | Dec 2030 | 5 |
| 24 | Village Of Bolingbrook STP #3 | Bolingbrook | 2.52 | ILL069744 | Dec 2030 | 18 |
| 25 | Pekin STP #1 | Pekin | 2.4 | ILL034495 | Dec 2030 | 7 |
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 Illinois
Anaerobic digesters and biogas in other states
Anaerobic digesters and biogas in Illinois: 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.