Clean Water Act discharge permit · NPDES MO0097675
AECI THOMAS HILL ENERGY CENTER, Clifton Hill, MO: NPDES MO0097675 discharge permit, effluent exceedances, inspections, penalties
- EffectivePermit status
- MajorDischarger class
- 24Pollutants under a numeric limit
- 8Pollutants with an effluent exceedance
AECI THOMAS HILL ENERGY CENTER, held by Associated Electric Cooperative, Inc., holds NPDES permit MO0097675, which discharges to M. Fk. Little Chariton R.. EPA’s file records it issued November 1, 2022 and expiring October 31, 2027. The status and dates are as EPA’s permit file stood when Velarion loaded it (October 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | AECI THOMAS HILL ENERGY CENTER |
|---|---|
| Permittee as filed | Associated Electric Cooperative, Inc. |
| NPDES ID | MO0097675 |
| Permit status | Effective |
| Permit type | Individual permit |
| Discharger class | Major discharger |
| Facility type | Not a publicly owned treatment works |
| Program | Industrial stormwater |
| Issued | November 1, 2022 |
| Expiration date | October 31, 2027 |
| Address | Clifton Hill, MO 65244 |
| Receiving water | M. Fk. Little Chariton R. |
| Receiving water impaired | 303(D) Listed |
| Subwatershed | Bee Creek-Middle Fork Little Chariton River (HUC 102802030405) |
| NAICS | 221112 – Fossil Fuel Electric Power Generation |
| SIC | 4911 – Electric Services |
| Other EPA IDs (FRS) | RCRA handler MOD053979316; ICIS-AIR source MO0000002917500001 |
Cited to the EPA ICIS-NPDES permit file (ECHO download) and EPA’s NAICS/SIC and component files, the same download; cross-program IDs from EPA’s FRS facility-registry crosswalk.
Effluent limits and exceedances
- 28Pollutants on file
- 24Under a numeric limit
- 12With a violation of any kind
- 8With an effluent exceedance
An effluent exceedance is a discharge monitoring report value over the permit’s numeric limit (EPA’s violation code E90). A violation of any kind also counts a report not filed. Each row is EPA’s own count for that pollutant.
| Pollutant or measure | Limits | Violations, any kind | Effluent exceedances | Latest exceedance | Largest exceedance, as filed |
|---|---|---|---|---|---|
| Solids, total suspended | 32 | 20 | 10 | August 31, 2023 | 154% over the limit |
| pH | 34 | 163 | 6 | July 31, 2026 | |
| Chlorine, total residual | 4 | 246 | 2 | October 31, 2022 | 1,547% over the limit |
| Nitrogen, ammonia total [as N] | 30 | 2 | 2 | February 28, 2018 | 383% over the limit |
| Chlorides + Sulfates | 10 | 2 | 2 | September 30, 2025 | 53% over the limit |
| Iron, total recoverable | 6 | 2 | 2 | June 30, 2020 | 57% over the limit |
| E. coli | 2 | 2 | 2 | June 30, 2023 | 15% over the limit |
| BOD, 5-day, 20 deg. C | 0 | 1 | 1 | January 31, 2010 | 16% over the limit |
| Solids, settleable | 0 | 199 | 0 | ||
| Pass/Fail Static 48Hr Acute Ceriodaphnia dubia | 0 | 18 | 0 | ||
| LC50 Static 48Hr Acute Pimephales promelas | 0 | 18 | 0 | ||
| Oil and grease [soxhlet extr.] tot. | 20 | 6 | 0 | ||
| Flow, in conduit or thru treatment plant | 30 | 0 | 0 | ||
| Sulfate, total [as SO4] | 10 | 0 | 0 | ||
| Aluminum, total recoverable | 10 | 0 | 0 | ||
| Chloride | 10 | 0 | 0 | ||
| Oxygen demand, chem. [high level] [COD] | 6 | 0 | 0 | ||
| Nitrite + Nitrate total [as N] | 6 | 0 | 0 | ||
| Phosphorus, total [as P] | 6 | 0 | 0 | ||
| Copper, total recoverable | 6 | 0 | 0 | ||
| Nitrogen, Kjeldahl, total [TKN] [water] | 6 | 0 | 0 | ||
| Toxicity [chronic], Ceriodaphnia dubia | 3 | 0 | 0 | ||
| Toxicity [chronic], Pimephales promelas [Fathead Minnow] | 3 | 0 | 0 | ||
| Temperature, water deg. fahrenheit | 2 | 0 | 0 | ||
| Boron, total recoverable | 2 | 0 | 0 | ||
| BOD, 5-day, total | 2 | 0 | 0 | ||
| Toxicity [acute], Ceriodaphnia dubia | 1 | 0 | 0 | ||
| Toxicity [acute], Pimephales promelas [Fathead Minnow] | 1 | 0 | 0 |
Cited to the EPA ICIS-NPDES limits and effluent violations files (ECHO download); up to 60 rows shown, most exceedances first.
Inspections, violations and enforcement
- 3Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| August 10, 2026 | Effluent Violations - Numeric effluent violation | ST6 |
| August 10, 2026 | Reporting Violations - Improper/ Incorrect Reporting | ST6 |
| August 28, 2020 | Reporting Violations - Improper/ Incorrect Reporting | ST6 |
Velarion’s copy of EPA’s ICIS-NPDES files does not include the inspections, formal enforcement actions and informal enforcement actions files, so this page shows none of them. EPA’s free Detailed Facility Report on ECHO lists this permit’s inspections, enforcement actions and penalties.
Cited to the EPA ICIS-NPDES violation, inspection and enforcement files (ECHO download); up to 50 rows of each shown, newest first.
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EPA publishes a free Detailed Facility Report for every permit on ECHO: its compliance status quarter by quarter, its inspections, and its enforcement actions and penalties. EPA also sends free notices of new inspections and enforcement actions through ECHO Notify; enter NPDES ID MO0097675 there.
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Figures from EPA’s ICIS-NPDES download, loaded October 14, 2026.