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Duson, Town of

Sewage treatment plant, Duson, Louisiana. NPDES permit LA0055085, in force until Sep 30, 2029. Last 12 months: over a limit 4 times (last June 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: outfall 001 form A quarterly (14 values), outfall 001 form Q quarterly (8 values), outfall 01A form A quarterly (3 values)
Last report on file
June 2026
Oct 2024 – Sep 2025
1 value over a limit, 0 required values missing, 0 of 28 reports late

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

Period endingOutfallParameterReportedLimitOver by
January 202601ANitrogen, ammonia total [as N], weekly average23.2 mg/L≤ 23 mg/L1%
February 2026001pH, instantaneous maximum9.58 SU≤ 9 SU—
March 2026001pH, instantaneous minimum5.77 SU≥ 6 SU—
June 2026001Solids, total suspended, monthly average45 lb/d≤ 43 lb/d5%

Limits in force (32)

ParameterStatisticLimitMonthsOutfall
Turbiditymonthly average≤ 150 NTUall year001
Oxygen, dissolved [DO]monthly average minimum≥ 5 mg/LJan, Feb, Dec001
Oxygen, dissolved [DO]monthly average minimum≥ 6 mg/LMar–Nov001
pHinstantaneous minimum≥ 6 SUall year001
pHinstantaneous maximum≤ 9 SUall year001
Solids, total suspendedmonthly average≤ 15 mg/Lall year001
Solids, total suspendedweekly average≤ 23 mg/Lall year001
Solids, total suspendedmonthly average≤ 43 lb/dall year001
Nitrogen, total [as N]monthly averagereport only (mg/L)all year001
Nitrogen, total [as N]daily maximumreport only (mg/L)all year001
Nitrogen, total [as N]monthly averagereport only (lb/d)all year001
Phosphorus, total [as P]monthly averagereport only (mg/L)all year001
Phosphorus, total [as P]daily maximumreport only (mg/L)all year001
Phosphorus, total [as P]monthly averagereport only (lb/d)all year001
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year001
Flow, in conduit or thru treatment plantweekly averagereport only (MGD)all year001
Chlorine, total residualinstantaneous maximumreport only (mg/L)all year001
Solids, total dissolvedmonthly average≤ 2139 lb/dall year001
Coliform, fecal generalmonthly geometric mean≤ 200 #/100mLall year001
Coliform, fecal generalweekly geometric mean≤ 400 #/100mLall year001
BOD, carbonaceous [5 day, 20 C]monthly average≤ 30 mg/LJan, Feb, Dec001
BOD, carbonaceous [5 day, 20 C]monthly average≤ 10 mg/LMar–Nov001
BOD, carbonaceous [5 day, 20 C]weekly average≤ 45 mg/LJan, Feb, Dec001
BOD, carbonaceous [5 day, 20 C]weekly average≤ 15 mg/LMar–Nov001
BOD, carbonaceous [5 day, 20 C]monthly average≤ 85 lb/dJan, Feb, Dec001
BOD, carbonaceous [5 day, 20 C]monthly average≤ 28 lb/dMar–Nov001
Nitrogen, ammonia total [as N]monthly average≤ 5 mg/LMar–Nov01A
Nitrogen, ammonia total [as N]monthly average≤ 15 mg/LJan, Feb, Dec01A
Nitrogen, ammonia total [as N]weekly average≤ 10 mg/LMar–Nov01A
Nitrogen, ammonia total [as N]weekly average≤ 23 mg/LJan, Feb, Dec01A
Nitrogen, ammonia total [as N]monthly average≤ 14 lb/dMar–Nov01A
Nitrogen, ammonia total [as N]monthly average≤ 43 lb/dJan, Feb, Dec01A

New limits from Oct 1, 2027

ParameterNew limitFromNew or tighterMedian, last 12 months× new limit
Chlorine, total residual, instantaneous maximum outfall 0010.033 mg/LOct 1, 2027new1.25 mg/L (9 values)37.9×
Nitrogen, ammonia total [as N], monthly average outfall 01A4.5 mg/LOct 1, 2029tighter0.069 mg/L (9 values, 3 below detection)0.0153×
Nitrogen, ammonia total [as N], monthly average outfall 01A13 lb/dOct 1, 2029tighter0.06 lb/d (9 values, 3 below detection)0.00462×
Nitrogen, ammonia total [as N], weekly average outfall 01A10 mg/LOct 1, 2029tighter0.082 mg/L (9 values, 3 below detection)0.0082×

How strict are these limits?

Cited limits by parameter: Louisiana'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/LA0055085 · MCP: https://passage-data.com/mcp