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Walnut Grove Potw

Sewage treatment plant, Walnut Grove, Mississippi. NPDES permit MS0020982, in force until Nov 30, 2027. Last 12 months: over a limit 6 times (last December 2025). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: form Y yearly
Renewal application due
Jun 3, 2027 · 180 days before expiry; your permit may set another date
Last report on file
December 2025
Oct 2024 – Sep 2025
3 values over a limit, 0 required values missing, 0 of 1 report late

Last 12 months (Oct 1, 2025 – Sep 30, 2026)

Period endingParameterReportedLimitOver by
December 2025BOD, 5-day, 20 deg. C, maximum monthly average28 mg/L≤ 18 mg/L56%
December 2025BOD, 5-day, 20 deg. C, maximum weekly average28 mg/L≤ 27 mg/L4%
December 2025BOD, 5-day, percent removal, minimum42 %≥ 65 %66%
December 2025Nitrogen, ammonia total [as N], maximum monthly average5.34 lb/d≤ 4.8 lb/d11%
December 2025Nitrogen, ammonia total [as N], maximum monthly average8.04 mg/L≤ 3 mg/L168%
December 2025Nitrogen, ammonia total [as N], maximum weekly average8.04 mg/L≤ 4.5 mg/L79%

Limits in force (34)

ParameterStatisticLimitMonths
Oxygen, dissolved [DO]minimum≥ 6 mg/Lall year
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 18 mg/Lall year
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 27 mg/Lall year
BOD, 5-day, 20 deg. Cmaximum monthly average≤ 29 lb/dall year
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 43.7 lb/dall year
BOD, 5-day, 20 deg. Cmaximum monthly averagereport only (mg/L)all year
BOD, 5-day, 20 deg. Cmaximum weekly averagereport only (mg/L)all year
BOD, 5-day, 20 deg. Cmaximum monthly averagereport only (lb/d)all year
BOD, 5-day, 20 deg. Cmaximum weekly averagereport only (lb/d)all year
pHminimum≥ 6 SUall year
pHmaximum≤ 9 SUall year
Solids, total suspendedmaximum monthly average≤ 90 mg/Lall year
Solids, total suspendedmaximum weekly average≤ 135 mg/Lall year
Solids, total suspendedmaximum monthly average≤ 146 lb/dall year
Solids, total suspendedmaximum weekly average≤ 218 lb/dall year
Solids, total suspendedmaximum monthly averagereport only (mg/L)all year
Solids, total suspendedmaximum weekly averagereport only (mg/L)all year
Solids, total suspendedmaximum monthly averagereport only (lb/d)all year
Solids, total suspendedmaximum weekly averagereport only (lb/d)all year
Nitrogen, total [as N]maximum monthly average≤ 18.62 lb/dall year
Nitrogen, total [as N]maximum weekly average≤ 27.93 lb/dall year
Nitrogen, ammonia total [as N]maximum monthly average≤ 3 mg/Lall year
Nitrogen, ammonia total [as N]maximum weekly average≤ 4.5 mg/Lall year
Nitrogen, ammonia total [as N]maximum monthly average≤ 4.8 lb/dall year
Nitrogen, ammonia total [as N]maximum weekly average≤ 7.2 lb/dall year
Phosphorus, total [as P]maximum monthly average≤ 8.42 lb/dall year
Phosphorus, total [as P]maximum weekly average≤ 12.63 lb/dall year
Flow, in conduit or thru treatment plantmaximum monthly average≤ .194 MGDall year
Chlorine, total residualmaximum monthly average≤ .193 mg/Lall year
Chlorine, total residualmaximum weekly average≤ .333 mg/Lall year
E. colimaximum monthly average≤ 126 #/100mLall year
E. colimaximum weekly average≤ 410 #/100mLall year
BOD, 5-day, percent removalminimum≥ 65 %all year
Solids, suspended percent removalminimum≥ 65 %all year

How strict are these limits?

Cited limits by parameter: Mississippi's rules and the federal ones.

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/MS0020982 · MCP: https://passage-data.com/mcp