Clean Water Act discharge permit · NPDES MO0056057
MERCER WWTF, Mercer, MO: NPDES MO0056057 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MinorDischarger class
- 11Pollutants under a numeric limit
- 9Pollutants with an effluent exceedance
MERCER WWTF, held by City of Mercer, holds NPDES permit MO0056057, which discharges to Tributary To Muddy Cr.. EPA’s file records it issued January 30, 2019 and expiring December 31, 2023. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 15, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | MERCER WWTF |
|---|---|
| Permittee as filed | City of Mercer |
| NPDES ID | MO0056057 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Individual permit |
| Discharger class | Minor discharger |
| Facility type | Publicly owned treatment works |
| Program | Publicly owned treatment works |
| Issued | January 30, 2019 |
| Expiration date | December 31, 2023 |
| Address | Mercer, MO 64661 |
| Receiving water | Tributary to Muddy Cr. |
| Subwatershed | Upper Muddy Creek (HUC 102801021101) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 13Pollutants on file
- 11Under a numeric limit
- 13With a violation of any kind
- 9With 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 |
|---|---|---|---|---|---|
| E. coli, colony forming units [CFU] | 0 | 31 | 3 | July 31, 2015 | 677% over the limit |
| Solids, total suspended | 2 | 28 | 3 | December 31, 2019 | 135% over the limit |
| Oil and grease [soxhlet extr.] tot. | 2 | 21 | 3 | December 31, 2018 | 70% over the limit |
| E. coli | 2 | 13 | 3 | July 31, 2020 | 99,999% over the limit |
| Nitrogen, ammonia total [as N] | 6 | 30 | 2 | May 31, 2024 | 82% over the limit |
| BOD, 5-day, 20 deg. C | 2 | 27 | 2 | December 31, 2013 | 171% over the limit |
| Solids, suspended percent removal | 1 | 4 | 2 | December 31, 2019 | 171% over the limit |
| BOD, 5-day, percent removal | 1 | 3 | 1 | March 31, 2019 | 57% over the limit |
| Coliform, fecal general | 0 | 1 | 1 | June 30, 2013 | 225% over the limit |
| pH | 2 | 23 | 0 | ||
| Flow, in conduit or thru treatment plant | 2 | 20 | 0 | ||
| Toxicity [acute], Ceriodaphnia dubia | 1 | 1 | 0 | ||
| Toxicity [acute], Pimephales promelas [Fathead Minnow] | 1 | 1 | 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
- 6Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| September 27, 2024 | Effluent Violations - Numeric effluent violation | ST6 |
| April 25, 2024 | Reporting Violations - Improper/ Incorrect Reporting | ST6 |
| April 25, 2024 | Permit Violations - Violation Specified in Comment | ST6 |
| June 17, 2021 | Reporting Violations - Failure to Submit DMRs | ST6 |
| April 29, 2019 | Reporting Violations - Failure to submit required report (non-DMR non-pretreatment) | ST6 |
| January 15, 2019 | Reporting Violations - Failure to Submit DMRs | 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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Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.