Activated sludge and clarifiers: wastewater treatment plants in Missouri
97 plants · 16% of the state · 418 MGD reported by 92 plants
Klarifi identifies 97 publicly owned wastewater treatment plants with activated sludge and clarifiers in Missouri, 16% of the 593 plants in the state (418 MGD reported by 92 plants). The largest is Metropolitan St. Louis Sewer District Bissell Point WWTP in St. Louis at 90.1 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 Missouri
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Metropolitan St. Louis Sewer District Bissell Point WWTP | St. Louis | 90.1 | MO0025178 | Aug 2031 | 14 |
| 2 | Metropolitan St. Louis Sewer District Lemay WWTP | St. Louis | 79.3 | MO0025151 | Aug 2031 | 0 |
| 3 | Little Blue Valley Sewer District | Independence | 29.2 | MOL101087 | Dec 2030 | 14 |
| 4 | Southwest WWTP | Springfield | 25.32 | MO0049522 | Jul 2025 | 0 |
| 5 | St. Joseph Water Protection Facility | Saint Joseph | 18.27 | MO0023043 | Nov 2025 | 4 |
| 6 | MSD Coldwater WWTP | Florissant | 14.3 | MO0025160 | Aug 2031 | 1 |
| 7 | Kc, Westside WWTP | Kansas City | 12.54 | MO0024929 | Jun 2026 | 2 |
| 8 | Metropolitan St Louis Sewer District-Grand Glaize Wastewater Treatment Plant | Valley Park | 10.4 | MO0101362 | Aug 2031 | 0 |
| 9 | MSD Lower Meramec WWTP | St. Louis | 7.6 | MO0127949 | Aug 2031 | 0 |
| 10 | O' Fallon Wastewater Treatment Plant | O'Fallon | 6.7 | MO0028720 | Mar 2025 | 0 |
| 11 | Joplin Turkey Creek WWTP | Joplin | 5.7 | MO0103349 | Sep 2022 | 64 |
| 12 | Shoal Creek Wastewater Treatment Facility | Joplin | 5.6 | MO0023256 | Mar 2023 | 9 |
| 13 | Jefferson City Rwrf | Jefferson City | 5.36 | MO0094846 | Mar 2025 | 0 |
| 14 | Rock Creek Waste Treatment | Independence | 5.07 | MO0089681 | Mar 2024 | 12 |
| 15 | St Peters Pws | Saint Peters | 4.83 | MO0030970 | Dec 2024 | 0 |
| 16 | Wentzville Pws | Wentzville | 4.34 | MO0093599 | Mar 2024 | 4 |
| 17 | Dcsd Wastewater Treatment Plant 2 | Weldon Spring | 4.28 | MO0116572 | Dec 2025 | 0 |
| 18 | Springfield NW WWTP | Springfield | 4.06 | MO0103039 | Jul 2025 | 0 |
| 19 | Duckett Creek Sanitation District Treatment Plant #1 | Saint Charles | 4.04 | MO0085472 | Jun 2021 | 0 |
| 20 | St Charles Missouri River WWTP | St. Charles | 3.73 | MO0058351 | Sep 2025 | 0 |
| 21 | MSD Fenton Waste Water Treatment Plant | Fenton | 3.6 | MO0086126 | Dec 2022 | 0 |
| 22 | Blue Springs, Sni A Bar WWTF | Grain Valley | 3.5 | MO0028886 | Nov 2028 | 16 |
| 23 | Carthage WWTP | Carthage | 2.92 | MO0039136 | Mar 2023 | 4 |
| 24 | Hannibal Pws | Hannibal | 2.69 | MO0093513 | Apr 2023 | 0 |
| 25 | Monett Wastewater Treatment Plant | Monett | 2.5 | MO0021440 | Jun 2029 | 17 |
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 Missouri
Activated sludge and clarifiers in other states
Activated sludge and clarifiers in Missouri: 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.