Peaks Island STP - Secondary Wastewater Treatment Plant, Portland, Maine

Peaks Island STP is a municipal wastewater treatment facility located on Peaks Island, part of Portland, Maine, in the United States. The plant serves a small population of 430 residents, providing secondary treatment to protect the surrounding coastal environment. The facility operates under the U.S. Clean Water Act, which requires secondary treatment for municipal wastewater discharges. With a designed capacity of 757.08 m³/day and an average daily flow of 378.54 m³/day, the plant operates at about 50% of its capacity, indicating room for future growth. Treated effluent from Peaks Island STP is discharged into Casco Bay, a coastal water body that ultimately connects to the Gulf of Maine and the North Atlantic Ocean. The bay supports diverse marine life, including fish, shellfish, and seabirds, making proper wastewater treatment essential for maintaining water quality and ecosystem health.

Peaks Island STP discharges treated wastewater into Casco Bay, a coastal embayment that flows into the Gulf of Maine and the North Atlantic Ocean. The bay is an ecologically sensitive area supporting diverse marine habitats, including eelgrass beds, shellfish populations, and migratory fish. Secondary treatment reduces organic pollutants and suspended solids, helping to protect water quality and marine life in this coastal ecosystem.