Activated sludge and clarifiers: wastewater treatment plants in Colorado
30 plants · 22% of the state · 66 MGD reported by 26 plants
Klarifi identifies 30 publicly owned wastewater treatment plants with activated sludge and clarifiers in Colorado, 22% of the 139 plants in the state (66 MGD reported by 26 plants). The largest is Persigo Wastewater Treatment Plant in Grand Junction at 10.37 MGD.
Activated sludge is the standard mechanical process for cities: aeration basins where bacteria consume organic matter, followed by clarifiers that settle the biomass out. These plants are identified by their circular or rectangular clarifiers and by the suspended-growth process code, and they are the main market for blowers, diffusers, clarifier mechanisms and instrumentation.
The largest activated sludge plants in Colorado
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Persigo Wastewater Treatment Plant | Grand Junction | 10.37 | CO0040053 | Dec 2022 | 1 |
| 2 | Greeley WWTP | Greeley | 8.34 | COL040258 | Dec 2030 | 13 |
| 3 | Big Dry Creek WWTP | Westminster | 6.94 | COR901608 | Jun 2029 | 388 |
| 4 | Parker Water + Sanitation District - North Water Reclamation Facility | Parker | 4.83 | COG072642 | Aug 2018 | 80 |
| 5 | Rainbow Park WWTP | Florence | 3.97 | CO0039748 | Feb 2020 | 0 |
| 6 | South Ft. Collins Sanit. Dist. | Fort Collins | 3.52 | CO0020737 | Jan 2018 | 1 |
| 7 | Northglenn WWTP | Brighton | 3.11 | CO0036757 | Dec 2024 | 7 |
| 8 | Town Of Windsor Sewarage Treatment Plant | Windsor | 2.58 | CO0020320 | May 2020 | 0 |
| 9 | Lafayette WWTF | Lafayette | 2.39 | COR900828 | Jun 2029 | 0 |
| 10 | City Of Louisville | Louisville | 2.34 | CO0023078 | Sep 2016 | 2 |
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 Colorado
Activated sludge and clarifiers in other states
Activated sludge and clarifiers in Colorado: 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: Activated sludge · Biological nutrient removal · Equalization tank · FOG · Centrate · all terms