Lagoon systems: wastewater treatment plants in New Jersey
9 plants · 8% of the state · 121 MGD combined
Klarifi identifies 9 publicly owned wastewater treatment plants with lagoon systems in New Jersey, 8% of the 118 plants in the state (121 MGD combined). The largest is Middlesex County Utilities Authority in Sayreville at 87.51 MGD.
Lagoon systems treat wastewater in large earthen ponds over weeks of retention time, with or without mechanical aeration. They serve thousands of small towns because they are cheap to run, but they struggle with ammonia and nutrient limits, fill with sludge over decades and are the plants most often converted or upgraded when a permit is renewed.
The largest lagoons 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 | Atlantic County Utilities Authority POTW | Atlantic City | 24.37 | NJL024473 | Dec 2030 | 0 |
| 3 | East Windsor Water Pollution Control Plant | East Windsor | 2.53 | NJ0023787 | Mar 2027 | 86 |
| 4 | Cape May Cnty MUA 7 Mile Beach Middle Rgnl Wtf | Cape May Court House | 2.46 | NJ0052990 | Jun 2026 | 3 |
| 5 | Molitor Water Pollution Control Facility | Chatham | 2.09 | NJ0024937 | Dec 2029 | 170 |
| 6 | Logan Township MUA | Bridgeport | 1.58 | NJ0027545 | Sep 2028 | 3 |
| 7 | Warren Twp Sewer Auth Stage 4 WWTP | Warren | 0.56 | NJ0022497 | Sep 2030 | 18 |
| 8 | Mercer County Correction Ctr WTP | Hopewell Twp | 0.06 | NJ0027715 | Sep 2024 | 31 |
| 9 | Hancocks Bridge STP | Hancocks Bridge | 0.02 | NJ0050423 | Dec 2024 | 204 |
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
Lagoon systems in other states
Lagoon systems 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: WWTP · POTW · Biosolids · Oxidation ditch · Anaerobic digester · all terms