Activated sludge and clarifiers: wastewater treatment plants in Louisiana
45 plants · 16% of the state · 189 MGD reported by 42 plants
Klarifi identifies 45 publicly owned wastewater treatment plants with activated sludge and clarifiers in Louisiana, 16% of the 277 plants in the state (189 MGD reported by 42 plants). The largest is South Wastewater Treatment Plant in Baton Rouge at 41.82 MGD.
Activated sludge is the standard mechanical process for cities: aeration basins where bacteria consume organic matter, followed by clarifiers that settle the biomass out. These plants are identified by their circular or rectangular clarifiers and by the suspended-growth process code, and they are the main market for blowers, diffusers, clarifier mechanisms and instrumentation.
The largest activated sludge plants in Louisiana
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | South Wastewater Treatment Plant | Baton Rouge | 41.82 | LA0036412 | Jun 2029 | 21 |
| 2 | Jefferson Parish Department Of Sewerage- East Bank WWTP | Elmwood | 28.23 | LA0066630 | Jul 2028 | 0 |
| 3 | Baton Rouge, City Of | Scotlandville | 20.18 | LA0036439 | Jul 2029 | 33 |
| 4 | Sewerage & Water Board Of New Orleans Westb Ank Sewage | New Orleans | 13.61 | LA0038105 | Nov 2029 | 1 |
| 5 | Wastewater Treatment Plant, Hudson Site | Alexandria | 8.46 | LA0041009 | Dec 2030 | 2 |
| 6 | Jefferson Parish Department Of Sewerage- Marrero WWTP | Marrero | 8.08 | LA0042048 | Oct 2026 | 5 |
| 7 | Monroe, City Of (wpc Cntr) | Monroe | 7.62 | LAL038741 | Dec 2030 | 78 |
| 8 | Plant B | Lake Charles | 6.53 | LAL036366 | Dec 2030 | 73 |
| 9 | Red River Wastewater Treatment Plant | Bossier City | 4.62 | LA0053716 | May 2028 | 0 |
| 10 | Shreveport North Regional WWTP | Shreveport | 3.78 | LAL042188 | Dec 2030 | 42 |
Contacts and project signals for every plant on this list
Klarifi adds verified decision-maker contacts, permit limits, discharge monitoring data and the capital projects planned in each city, filterable by technology, size and compliance record.
Other technologies in Louisiana
Activated sludge and clarifiers in other states
Activated sludge and clarifiers in Louisiana: 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 October 26, 2026.
Wastewater terms: Activated sludge · Biological nutrient removal · Equalization tank · Ozonation · Oxidation ditch · all terms