Deer Island Wastewater Treatment Facility
Winthrop, MA · Suffolk County · Publicly Owned Treatment Works
- Average flow
- 233.7 MGD
- Design flow
- 480 MGD
- NPDES permit
- MA0103284
- Administratively continued
- Permit expires
- July 2005
- Population served
- 2,317,098
- CWNS 2022
Deer Island Wastewater Treatment Facility is a publicly owned wastewater treatment works in Winthrop, Suffolk County, Massachusetts treating an average of 233.7 million gallons per day against a permitted design capacity of 480 MGD, serving about 2,317,098 residents. Treatment on site includes biogas silos, biogas balloons, biosolids anaerobic digestion with energy recovery, biosolids chemical addition, biosolids drying and other unit processes. It discharges under NPDES permit MA0103284 (administratively continued), which expires in July 2005, with 3 recorded violations in the last three years.
Treatment technology
Treatment structures identified at this facility. Exact unit counts are available in Klarifi.
Biogas silos
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Biogas balloons
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Biosolids Anaerobic Digestion with Energy Recovery
unit processBiosolids Chemical Addition
unit processBiosolids Drying
unit processBiosolids Mechanical Dewatering
unit processBiosolids Thickening
unit processDechlorination
unit processDisinfection, chlorine/ chloramine
unit processPrimary Clarification or Sedimentation
unit processScreening
unit processSuspended Growth, Aerobic
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Compliance snapshot (last 3 years)
- Total violations
- 3
- Effluent violations
- 2
Based on NPDES Discharge Monitoring Reports. Full violation history, parameters and discharge data available in the Klarifi platform.
Key contacts
4 verified contacts for Deer Island Wastewater Treatment Facility, with validated emails and direct phone numbers.
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Names, validated emails and direct phone numbers for decision-makers at Deer Island Wastewater Treatment Facility, plus the full compliance history and discharge data.
Nearby wastewater treatment plants in Massachusetts
Hull · 4 mi away
1.03 MGD
Cohasset · 11 mi away
0.21 MGD
Salem · 13 mi away
17.57 MGD
Rockland · 17 mi away
2 MGD
Manchester · 18 mi away
0.29 MGD
Wayland · 21 mi away
0.03 MGD
Brockton · 21 mi away
9.9 MGD
Concord · 21 mi away
0.68 MGD
Deer Island Wastewater Treatment Facility: 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 September 2, 2025.