Activated sludge and clarifiers: wastewater treatment plants in New Jersey
59 plants · 50% of the state · 426 MGD reported by 56 plants
Klarifi identifies 59 publicly owned wastewater treatment plants with activated sludge and clarifiers in New Jersey, 50% of the 118 plants in the state (426 MGD reported by 56 plants). The largest is Middlesex County Utilities Authority in Sayreville at 87.51 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 New Jersey
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Middlesex County Utilities Authority | Sayreville | 87.51 | NJ0020141 | Jun 2020 | 21 |
| 2 | Bergen County Utilities Authority | Little Ferry | 70 | NJ0020028 | Mar 2030 | 178 |
| 3 | Essex & Union Cnty Joint Meeting STP | Elizabeth | 50.33 | NJ0024741 | Mar 2030 | 145 |
| 4 | Atlantic County Utilities Authority POTW | Atlantic City | 24.37 | NJL024473 | Dec 2030 | 0 |
| 5 | Ocean Cnty Util Auth Nwpcf | Bricktown | 22.38 | NJ0028142 | Mar 2026 | 0 |
| 6 | Ocean Cnty Util Auth Cwpcf | Bayville | 17.97 | NJL029408 | Dec 2030 | 0 |
| 7 | Somerset Raritian Valley Sewerage | Bridgewater | 16.4 | NJ0024864 | Nov 2030 | 12 |
| 8 | Gloucester Cnty Util Auth STP | West Deptford Twp | 15.52 | NJ0024686 | Dec 2026 | 15 |
| 9 | Monmouth Cnty Bayshore Outfall Auth Belford Pump Station | Belford | 13.96 | NJ0024694 | Sep 2026 | 3 |
| 10 | North Hudson Sewerage Auth WWTP | Hoboken | 11.73 | NJ0026085 | Mar 2029 | 0 |
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 New Jersey
Activated sludge and clarifiers in other states
Activated sludge and clarifiers in New Jersey: 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 · POTW · MGD · all terms