South Essex Wastewater Treatment Plant
Salem, MA · Essex County · Publicly Owned Treatment Works
- Average flow
- 17.57 MGD
- Design flow
- —
- NPDES permit
- MAL100501
- Effective
- Permit expires
- December 2030
- Population served
- 376,847
- CWNS 2022
South Essex Wastewater Treatment Plant is a publicly owned wastewater treatment works in Salem, Essex County, Massachusetts treating an average of 17.57 million gallons per day, serving about 376,847 residents. Treatment on site includes biosolids mechanical dewatering, biosolids thickening, dechlorination, disinfection, chlorine/ chloramine, primary clarification or sedimentation and other unit processes. It discharges under NPDES permit MAL100501 (effective), which expires in December 2030, with 33 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Biosolids Mechanical Dewatering
unit processBiosolids Thickening
unit processDechlorination
unit processDisinfection, chlorine/ chloramine
unit processPrimary Clarification or Sedimentation
unit processScreening
unit processSuspended Growth, Aerobic
unit processUnlock exact unit counts →
Compliance snapshot (last 3 years)
- Total violations
- 33
- Effluent violations
- 33
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
4 verified contacts for South Essex Wastewater Treatment Plant, with validated emails and direct phone numbers.
Unlock 4 verified contacts (1 more than shown)
Names, validated emails and direct phone numbers for decision-makers at South Essex Wastewater Treatment Plant, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Massachusetts
Manchester · 6 mi away
0.29 MGD
Ipswich · 12 mi away
0.5 MGD
Winthrop · 13 mi away
233.7 MGD
Hull · 15 mi away
1.03 MGD
North Andover · 18 mi away
21.7 MGD
Haverhill · 19 mi away
6.58 MGD
Newburyport · 19 mi away
1.45 MGD
Cohasset · 20 mi away
0.21 MGD
South Essex Wastewater Treatment Plant: frequently asked 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; facility record last updated December 22, 2024.