Activated sludge and clarifiers: wastewater treatment plants in New Jersey
62 plants · 51% of the state · 412 MGD reported by 58 plants
Klarifi identifies 62 publicly owned wastewater treatment plants with activated sludge and clarifiers in New Jersey, 51% of the 122 plants in the state (412 MGD reported by 58 plants). The largest is Middlesex County Utilities Authority in Sayreville at 77.42 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 | 77.42 | NJ0020141 | Jun 2020 | 17 |
| 2 | Bergen County Utilities Authority | Little Ferry | 63.2 | NJ0020028 | Mar 2030 | 176 |
| 3 | Essex & Union Cnty Joint Meeting STP | Elizabeth | 44.93 | NJ0024741 | Mar 2030 | 145 |
| 4 | Atlantic County Utilities Authority POTW | Atlantic City | 24.52 | NJL024473 | Dec 2030 | 0 |
| 5 | Ocean Cnty Util Auth Nwpcf | Bricktown | 22.16 | NJ0028142 | Mar 2026 | 0 |
| 6 | Rahway Valley Sewerage Authority | Rahway | 19.3 | NJL024643 | Dec 2030 | 77 |
| 7 | Ocean Cnty Util Auth Cwpcf | Bayville | 17.6 | NJL029408 | Dec 2030 | 0 |
| 8 | Gloucester Cnty Util Auth STP | West Deptford Twp | 15.16 | NJ0024686 | Dec 2026 | 15 |
| 9 | Somerset Raritian Valley Sewerage | Bridgewater | 12.98 | NJ0024864 | Nov 2030 | 9 |
| 10 | Monmouth Cnty Bayshore Outfall Auth Belford Pump Station | Belford | 12.8 | NJ0024694 | Sep 2026 | 3 |
| 11 | North Hudson Sewerage Auth WWTP | Hoboken | 11.5 | NJ0026085 | Mar 2029 | 0 |
| 12 | Rockaway Valley Reg Sa | Boonton | 9.09 | NJ0022349 | Sep 2024 | 117 |
| 13 | Par Troy Hills Twp MUA WWTP @ Whippany River | Parsippany | 7.98 | NJG124753 | Jan 2028 | 88 |
| 14 | Middletown Twp Slf Belford Section | Middletown | 7.01 | NJ0025356 | Dec 2025 | 4 |
| 15 | Pine Brook STP | Manalapan | 5.83 | NJ0023728 | Sep 2026 | 0 |
| 16 | Township Of Wayne | Wayne | 5.72 | NJ0028002 | Mar 2026 | 38 |
| 17 | Ewing Lawrence Sewer Auth | Lawrenceville | 5.5 | NJ0024759 | Sep 2023 | 96 |
| 18 | Two Bridges Wastewater Treatment Plant | Lincoln Park | 4.45 | NJ0029386 | Sep 2025 | 0 |
| 19 | Bergen County Utilities Authority | Edgewater | 3.52 | NJ0020591 | Apr 2017 | 151 |
| 20 | Willingboro Water Pollution Control Plant | Willingboro | 3 | NJ0023361 | Dec 2030 | 8 |
| 21 | Caldwell Boro MUA Caldwell WWTP | West Caldwell | 2.98 | NJ0020427 | Sep 2028 | 68 |
| 22 | Cape May Cnty MUA Ocean City WWTP | Ocean City | 2.57 | NJ0035343 | Jun 2026 | 10 |
| 23 | Morristown Sewer Utility | Morristown | 2.57 | NJ0025496 | Mar 2026 | 12 |
| 24 | North Bergen Twp MUA Woodcliff STP | North Bergen | 2.41 | NJ0029084 | Jun 2028 | 17 |
| 25 | East Windsor Water Pollution Control Plant | East Windsor | 2.38 | NJ0023787 | Mar 2027 | 86 |
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 September 11, 2026.