Anaerobic digesters and biogas: US wastewater treatment plants
1,583 plants in 49 states · 10,561 MGD reported by 1,448 plants · 1 planning upgrades
Klarifi identifies 1,583 publicly owned wastewater treatment plants with anaerobic digesters and biogas in the United States (10,561 MGD reported by 1,448 plants). The largest is Metropolitan Water Reclamation in Chicago, IL at 281.73 MGD. Each state below links to its own list with every plant.
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.
Anaerobic digesters and biogas by state
146 plants
138 plants
112 plants
108 plants
97 plants
93 plants
93 plants
74 plants
71 plants
68 plants
55 plants
32 plants
31 plants
30 plants
28 plants
26 plants
23 plants
23 plants
19 plants
19 plants
18 plants
17 plants
17 plants
17 plants
16 plants
15 plants
15 plants
15 plants
15 plants
14 plants
14 plants
14 plants
14 plants
13 plants
12 plants
12 plants
9 plants
8 plants
7 plants
6 plants
6 plants
5 plants
5 plants
4 plants
3 plants
2 plants
2 plants
1 plants
1 plants
The largest plants with anaerobic digesters in the US
With permit expiry dates: the largest US plants with anaerobic digesters →
Other treatment technologies
Anaerobic digesters and biogas: 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 · Ozonation · Activated sludge · all terms