Islesboro Treatment Facility: Secondary Wastewater Plant on Islesboro, Maine

The Islesboro Treatment Facility is a municipal wastewater plant located on Pendleton Point Road in Islesboro, Maine, serving a small island community of 158 people. As a coastal facility within 10 km of the Atlantic Ocean, it plays a critical role in protecting the pristine waters of Penobscot Bay. The plant provides secondary treatment, which is the standard required by the U.S. Clean Water Act for municipal wastewater facilities. With a designed capacity of 242.27 million gallons per year and an annual discharge volume of 37.85 million gallons, the plant operates well below its capacity, ensuring effective treatment for the small population served. The treated effluent is discharged into the coastal waters of Penobscot Bay, which ultimately flows into the Gulf of Maine and the North Atlantic Ocean. This region supports diverse marine life, including lobster, fish, and seabirds, and is an important ecological and economic resource for the state of Maine.

The plant discharges into Penobscot Bay, a large estuary on the Gulf of Maine that drains into the North Atlantic Ocean. The bay supports a rich ecosystem of marine species, including commercially important lobster and groundfish, and provides critical habitat for migratory seabirds. The coastal waters are sensitive to nutrient pollution, making effective wastewater treatment essential for maintaining water quality and ecosystem health.