MSD Lower Meramec WWTP
St. Louis, MO · St. Louis County · Publicly Owned Treatment Works
- Average flow
- 7.6 MGD
- Design flow
- —
- NPDES permit
- MO0127949
- Effective
- Permit expires
- August 2031
- Population served
- 68,482
- CWNS 2022
MSD Lower Meramec WWTP is a publicly owned wastewater treatment works in St. Louis, St. Louis County, Missouri treating an average of 7.6 million gallons per day, serving about 68,482 residents. Treatment on site includes clarifiers, aerated lagoons, uncovered lagoons, biogas silos, biogas balloons and other unit processes. It discharges under NPDES permit MO0127949 (effective), which expires in August 2031, with 0 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Clarifiers
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Aerated lagoons
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Uncovered lagoons
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Biogas silos
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Biogas balloons
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Biosolids Thickening
unit processDechlorination
unit processDisinfection, chlorine/ chloramine
unit processPrimary Clarification or Sedimentation
unit processScreening
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Compliance snapshot (last 3 years)
- Total violations
- 0
- Effluent violations
- 0
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
1 verified contact for MSD Lower Meramec WWTP, with validated emails and direct phone numbers.
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Names, validated emails and direct phone numbers for decision-makers at MSD Lower Meramec WWTP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Missouri
Imperial · 3 mi away
1.42 MGD
Barnhart · 6 mi away
0.48 MGD
Fenton · 8 mi away
1.71 MGD
Barnhart · 8 mi away
0.05 MGD
Fenton · 8 mi away
0.0018 MGD
Fenton · 8 mi away
3.6 MGD
House Springs · 9 mi away
0.003 MGD
St. Louis · 9 mi away
79.3 MGD
MSD Lower Meramec WWTP: frequently asked 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; facility record last updated April 24, 2025.