St Louis WWTP
St. Louis, MI · Gratiot County · Publicly Owned Treatment Works
- Average flow
- 0.59 MGD
- Design flow
- —
- NPDES permit
- MI0021555
- Effective
- Permit expires
- October 2027
- Population served
- 8,572
- CWNS 2022
St Louis WWTP is a publicly owned wastewater treatment works in St. Louis, Gratiot County, Michigan treating an average of 0.59 million gallons per day, serving about 8,572 residents. Treatment on site includes clarifiers, uncovered lagoons, carrousels / oxidation ditches, biogas silos. It discharges under NPDES permit MI0021555 (effective), which expires in October 2027, with 9 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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Uncovered lagoons
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Carrousels / oxidation ditches
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Biogas silos
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Compliance snapshot (last 3 years)
- Total violations
- 9
- Effluent violations
- 1
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
Decision-makers at St Louis WWTP.
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Ithaca · 9 mi away
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Merrill · 13 mi away
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Mount Pleasant · 13 mi away
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Mount Pleasant · 16 mi away
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Mt Pleasant · 17 mi away
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Ashley · 17 mi away
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St Louis 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 March 6, 2025.