Oxidation ditches: wastewater treatment plants in New Jersey
17 plants · 14% of the state · 66 MGD reported by 16 plants
Klarifi identifies 17 publicly owned wastewater treatment plants with oxidation ditches in New Jersey, 14% of the 122 plants in the state (66 MGD reported by 16 plants). The largest is Essex & Union Cnty Joint Meeting STP in Elizabeth at 44.93 MGD.
Oxidation ditches are ring-shaped activated sludge reactors with long retention times, common at plants between 0.5 and 10 MGD. They are recognisable from the air by their looped channels and rely on surface aerators or brush rotors, which are frequent replacement and energy-efficiency projects.
The largest oxidation ditch plants in New Jersey
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Essex & Union Cnty Joint Meeting STP | Elizabeth | 44.93 | NJ0024741 | Mar 2030 | 145 |
| 2 | Rockaway Valley Reg Sa | Boonton | 9.09 | NJ0022349 | Sep 2024 | 117 |
| 3 | Caldwell Boro MUA Caldwell WWTP | West Caldwell | 2.98 | NJ0020427 | Sep 2028 | 68 |
| 4 | Molitor Water Pollution Control Facility | Chatham | 1.91 | NJ0024937 | Dec 2029 | 170 |
| 5 | Elmwood WTP | Marlton | 1.73 | NJ0024040 | Jun 2031 | 20 |
| 6 | Harrison Brook STP | Liberty Corner | 1.29 | NJ0022845 | Mar 2027 | 6 |
| 7 | Long Hill Township STP | Stirling | 0.9 | NJ0024465 | Sep 2023 | 60 |
| 8 | Chatham Twp DPW Main STP Water Pollution Control Plant | Chatham | 0.71 | NJ0020290 | Dec 2030 | 64 |
| 9 | Wanaque Valley Rgnl Sewer Auth Treatment Plant | Wanaque | 0.65 | NJ0053759 | Jun 2027 | 38 |
| 10 | Readington Lebanon Sewer Auth | Whitehouse | 0.58 | NJ0098922 | Jun 2029 | 30 |
| 11 | Harrison Township Treatment Pl | Mullica Hill | 0.3 | NJ0020532 | Jun 2031 | 122 |
| 12 | Buena Borough MUA Cs-Septics | Buena | 0.27 | NJ0021717 | Mar 2025 | 0 |
| 13 | Stony Brook Rgnl Sewerage Auth | Hopewell | 0.14 | NJ0035301 | Dec 2025 | 4 |
| 14 | Montgomery Twp MUA Cherry Valley STP | Skillman | 0.13 | NJ0069523 | Sep 2026 | 98 |
| 15 | Warren Twp Sewer Auth Stage 5 STP | Warren | 0.09 | NJ0050369 | Jun 2025 | 8 |
| 16 | Frenchtown Wastewater Treatment Plant | Frenchtown | 0.08 | NJ0029831 | Mar 2028 | 25 |
| 17 | Washington Boro WWTP | Washington | — | NJ0021113 | Jun 2029 | 91 |
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
Oxidation ditches in other states
Oxidation ditches 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.