Metropolitan St. Louis Sewer District Lemay WWTP
St. Louis, MO · St. Louis County · Publicly Owned Treatment Works
- Average flow
- 79.3 MGD
- Design flow
- —
- NPDES permit
- MO0025151
- Effective
- Permit expires
- August 2031
- Population served
- 453,428
- CWNS 2022
Metropolitan St. Louis Sewer District Lemay WWTP is a publicly owned wastewater treatment works in St. Louis, St. Louis County, Missouri treating an average of 79.3 million gallons per day, serving about 453,428 residents. Treatment on site includes clarifiers, biogas silos, biosolids incineration, disinfection, uv, screening. It discharges under NPDES permit MO0025151 (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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Biogas silos
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Biosolids Incineration
unit processDisinfection, UV
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
2 verified contacts for Metropolitan St. Louis Sewer District Lemay WWTP, with validated emails and direct phone numbers.
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Names, validated emails and direct phone numbers for decision-makers at Metropolitan St. Louis Sewer District Lemay WWTP, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Missouri
Fenton · 9 mi away
3.6 MGD
St. Louis · 9 mi away
7.6 MGD
Fenton · 10 mi away
1.71 MGD
St. Louis · 11 mi away
90.1 MGD
Valley Park · 11 mi away
10.4 MGD
Fenton · 12 mi away
0.0018 MGD
Imperial · 12 mi away
1.42 MGD
Barnhart · 15 mi away
0.48 MGD
Metropolitan St. Louis Sewer District Lemay 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 May 20, 2025.