Chlorine disinfection: wastewater treatment plants in Maine
47 plants · 51% of the state · 26 MGD combined
Klarifi identifies 47 publicly owned wastewater treatment plants with chlorine disinfection in Maine, 51% of the 92 plants in the state (26 MGD combined). The largest is Bangor Wastewater Treatment Facility in Bangor at 7.09 MGD.
Chlorine or chloramine disinfection, often followed by dechlorination before discharge, remains the most common effluent disinfection in the United States. Plants on gas chlorine are candidates for conversion to hypochlorite or UV, a recurring capital project driven by safety rules and permit limits on residual chlorine.
The largest plants with chlorine disinfection in Maine
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Bangor Wastewater Treatment Facility | Bangor | 7.09 | ME0100781 | Jul 2031 | 14 |
| 2 | Westbrook Waste Water Treatmemt Facility | Westbrook | 3.05 | ME0100846 | Jul 2022 | 26 |
| 3 | Brewer Wastewater Treatment Facility | Brewer | 1.47 | ME0100072 | Nov 2029 | 2 |
| 4 | Old Town Wastewater Treatment Facility | Old Town | 1.09 | ME0100471 | Sep 2029 | 2 |
| 5 | Old Orchard Beach Wastewater Treatment Facility | Old Orchard Beach | 0.99 | ME0101524 | May 2020 | 13 |
| 6 | York Wastewater Treatment Facility | York | 0.99 | ME0101222 | Mar 2030 | 12 |
| 7 | Gardiner WWTF | Gardiner | 0.97 | ME0101702 | Oct 2021 | 1 |
| 8 | Bar Harbor WWTF Main Facility | Bar Harbor | 0.91 | ME0101214 | Jan 2021 | 9 |
| 9 | Falmouth Waste Water Treatment Facility | Falmouth | 0.89 | ME0100218 | Dec 2023 | 3 |
| 10 | Pittsfield Wastewater Treatment Facility | Pittsfield | 0.71 | ME0100528 | Jun 2030 | 20 |
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 Maine
Chlorine disinfection in other states
Chlorine disinfection in Maine: 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: Tertiary treatment · Ozonation · WWTP · Centrate · Activated sludge · all terms