SOMESVILLE STP Wastewater Treatment Plant, Bar Harbor, Maine

SOMESVILLE STP is a municipal wastewater treatment plant located in Bar Harbor, Maine, United States. It serves a small population of 455 residents in the Northeast Harbor area of Mount Desert Island. The plant is situated at 24 Sinclair Road, near the coastal environment of Hancock County. The facility provides secondary treatment, which is the standard level required under the U.S. Clean Water Act for municipal plants. With a designed capacity of 757.08 m³/day and an actual discharge volume of 302.83 m³/day, the plant operates well within its capacity. As a small-scale facility, it is subject to EPA National Pollutant Discharge Elimination System (NPDES) permitting, administered by the Maine Department of Environmental Protection. The treated effluent is discharged into a local water body that ultimately drains into the Gulf of Maine, part of the larger Atlantic Ocean. The plant's proximity to the coast (within 10 km) means its discharge can influence nearby marine ecosystems, including shellfish habitats and coastal waters that support tourism and fishing in the Bar Harbor region.

The plant discharges into a small coastal watershed on Mount Desert Island, which drains into Frenchman Bay and then the Gulf of Maine. This region supports diverse marine life, including lobster, fish, and migratory seabirds. The coastal waters are ecologically sensitive due to nutrient loading risks from wastewater, which can affect water quality and shellfish harvesting areas.