Activated sludge and clarifiers: wastewater treatment plants in Missouri
103 plants · 15% of the state · 545 MGD reported by 97 plants
Klarifi identifies 103 publicly owned wastewater treatment plants with activated sludge and clarifiers in Missouri, 15% of the 671 plants in the state (545 MGD reported by 97 plants). The largest is Metropolitan St. Louis Sewer District Bissell Point WWTP in St. Louis at 123.06 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 | 123.06 | MO0025178 | Aug 2031 | 14 |
| 2 | Metropolitan St. Louis Sewer District Lemay WWTP | St. Louis | 105.45 | MO0025151 | Aug 2031 | 6 |
| 3 | Little Blue Valley Sewer District | Independence | 39.13 | MOL101087 | Dec 2030 | 14 |
| 4 | Southwest WWTP | Springfield | 30.9 | MO0049522 | Jul 2025 | 0 |
| 5 | MSD Coldwater WWTP | Florissant | 22.75 | MO0025160 | Aug 2031 | 1 |
| 6 | St. Joseph Water Protection Facility | Saint Joseph | 20.69 | MO0023043 | Nov 2025 | 4 |
| 7 | Kc, Westside WWTP | Kansas City | 14.89 | MO0024929 | Jun 2026 | 2 |
| 8 | Metropolitan St Louis Sewer District-Grand Glaize Wastewater Treatment Plant | Valley Park | 12.6 | MO0101362 | Aug 2031 | 0 |
| 9 | MSD Lower Meramec WWTP | St. Louis | 9.68 | MO0127949 | Aug 2031 | 0 |
| 10 | Joplin Turkey Creek WWTP | Joplin | 9.49 | MO0103349 | Sep 2022 | 65 |
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 October 26, 2026.
Wastewater terms: Activated sludge · Biological nutrient removal · Equalization tank · Lift station · Inflow and infiltration · all terms