Amherst Collection System Wastewater Treatment Plant, New Hampshire

The Amherst Collection System is a municipal wastewater treatment facility located at 145 Amherst Street in Amherst, New Hampshire, United States. Serving a small population of 407 residents, this plant is part of the local infrastructure managed by the town. The facility operates under the regulatory framework of the U.S. Clean Water Act, which requires secondary treatment for municipal wastewater discharges. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. With a designed capacity of 166.56 units and an actual discharge volume of 71.92 units, the facility operates well below its capacity, indicating room for future growth. The plant's permit is issued by the New Hampshire Department of Environmental Services under the National Pollutant Discharge Elimination System (NPDES). The treated effluent is discharged into a local water body that eventually drains into the Merrimack River watershed, which flows to the Atlantic Ocean. This inland location, more than 50 km from the coast, reduces direct marine impact. The plant plays a key role in protecting local streams and groundwater quality in the Amherst area.

The Amherst Collection System discharges into a tributary of the Merrimack River, which flows through New Hampshire and Massachusetts before reaching the Atlantic Ocean. The Merrimack River watershed supports diverse aquatic life and provides drinking water for downstream communities. The plant's secondary treatment helps reduce nutrient loading and protect the ecological health of this important river system.