Anaerobic digesters and biogas projects in US capital improvement plans
136 planned projects · $946M · 84 cities in 30 states
Digester tank rehabilitation, covers, mixing and heating systems, and biogas use from flares to combined heat and power and renewable natural gas. Concentrated at plants above 5 MGD.
Klarifi's extraction of published capital improvement plans finds 136 digester and biogas projects in 84 cities with a combined planning budget of $946M, the largest being Re-Gen Phase III in Arlington, VA at $210M. The list below ranks the 25 largest by budget; every city links to its full capital plan page.
The largest digester and biogas projects
| # | Project | City | Budget | Years |
|---|---|---|---|---|
| 1 | Re-Gen Phase III | Arlington, VA | $210M | 2025–2029 |
| 2 | West Boise Water Renewal Facility | Boise, ID | $128M | 2026–2030 |
| 3 | Disinfection and Digestion Upgrade | Mankato, MN | $80M | 2025–2026 |
| 4 | Patapsco Sludge Digestion Facilities | Baltimore, MD | $69M | 2031 |
| 5 | R.M. Clayton Digester Improvements | Atlanta, GA | $54M | 2026–2030 |
| 6 | Digester No. 4 | Longmont, CO | $30M | 2027–2029 |
| 7 | WPCP | Digester Rehabilitation Project | Davenport, IA | $27M | 2026–2028 |
| 8 | Bio Solids Facilities Enhancements | Fallston, MD | $27M | 2025–2029 |
| 9 | Digesters (2-years) | Jackson, MI | $24M | 2027–2029 |
| 10 | Wastewater OWTP: Digester/Cogeneration Improvements | Oxnard, CA | $17M | 2025–2029 |
| 11 | Iron Bridge Flow EQ System Improvements | Orlando, FL | $16M | 2024–2026 |
| 12 | SW Digester 3 | Saint Petersburg, FL | $16M | 2026–2030 |
| 13 | SWWTP Digester Process Expansion, Phase II | Columbus, OH | $15M | 2025 |
| 14 | Energy Improvements at Wastewater Facilities | Honolulu, HI | $13M | 2025–2027 |
| 15 | INF - NE Digester Mixing Project | Lincoln, NE | $12M | 2025–2029 |
| 16 | Wastewater Treatment Plant Anaerobic Digester Improvements | Richland, WA | $11M | 2025–2027 |
| 17 | SW CHP Generator Replacement | Saint Petersburg, FL | $10M | 2027 |
| 18 | WWTP - Phase 2 Digester Upgrade | Walla Walla, WA | $10M | 2024–2026 |
| 19 | Kitsap County Solids and Liquid Hauled Waste Upgrade | Poulsbo, WA | $9M | 2025–2028 |
| 20 | CBWTP Digester 2-4 Upgrade | Portland, OR | $9M | 2025–2029 |
| 21 | Southwest Treatment Plant - Biogas Conversion to Renewable Natural Gas | Springfield, MO | $8M | 2025 |
| 22 | WWTP New Digester Addition | Columbia, MO | $8M | 2026–2029 |
| 23 | Primary Digester | Warrenton, VA | $6M | 2026–2027 |
| 24 | WWTP FMC Digesters | Wichita, KS | $6M | 2025 |
| 25 | WWTP-Second Digester | Burlington, IA | $6M | 2029 |
All 136 digester and biogas projects, with descriptions and contacts
Every line item with its description, page reference and source document, filterable by state, budget and start year, linked to the treatment plants and decision-makers in each city, and refreshed as new plans are adopted.
Cities with the most digester and biogas projects
| City | Projects | Budget |
|---|---|---|
| Hanover, NH | 11 | $814K |
| Lincoln, NE | 6 | $18M |
| Spokane, WA | 6 | $17M |
| Midland, MI | 4 | $3M |
| Alpena, MI | 4 | $386K |
| Antioch, IL | 4 | $80K |
| Saint Petersburg, FL | 3 | $26M |
| Mankato, MN | 2 | $80M |
| Baltimore, MD | 2 | $72M |
| Orlando, FL | 2 | $22M |
| Portland, OR | 2 | $12M |
| Wooster, OH | 2 | $7M |
States with the most digester and biogas projects
| State | Projects | Budget |
|---|---|---|
| Michigan | 28 | $36M |
| Washington | 12 | $55M |
| New Hampshire | 11 | $814K |
| California | 9 | $31M |
| Iowa | 7 | $40M |
| Illinois | 7 | $2M |
| Nebraska | 6 | $18M |
| Minnesota | 5 | $82M |
| Florida | 5 | $48M |
| Ohio | 5 | $24M |
| Oregon | 4 | $18M |
| Wisconsin | 4 | $5M |
Planned spend by start year
Before 2026
$500M
51 items
2026
$286M
40 items
2027
$69M
11 items
2028
$11M
14 items
2029
$8M
6 items
2030
$3M
4 items
2031
$69M
1 items
2032 and later
$732K
9 items
Other project types
Anaerobic digesters and biogas project questions
Sources and methodology
Budgets and years are as published in each city’s capital improvement plan or adopted budget. Klarifi extracts the water, sewer and wastewater line items from the published document, keeps the page reference for each one, and assigns a project type from the title and description with a keyword classifier. Figures are planning budgets, not awarded contracts, and can change when a plan is re-adopted.
Data refreshed September 11, 2026.