NASHVILLE STP Wastewater Treatment Plant, Castleton Township, Michigan

NASHVILLE STP is a municipal wastewater treatment plant located in Castleton Township, Barry County, Michigan. The plant serves a small community of approximately 998 residents, providing secondary treatment to meet state and federal water quality standards. The plant has a designed capacity of 757.08 thousand cubic meters and currently treats an annual discharge volume of 605.67 thousand cubic meters. As a secondary treatment facility, it utilizes biological processes to reduce organic matter and suspended solids before discharge. Under the U.S. Clean Water Act, such plants operate under National Pollutant Discharge Elimination System (NPDES) permits issued by the Michigan Department of Environment, Great Lakes, and Energy (EGLE). The treated effluent is discharged into local waterways within the Grand River watershed, which ultimately drains into Lake Michigan. The plant plays a key role in protecting downstream water quality and aquatic habitats in this ecologically sensitive region of the Great Lakes basin.

The plant discharges into receiving waters that flow through the Grand River watershed, a major tributary system draining into Lake Michigan. This area supports diverse aquatic life, including fish species such as walleye and smallmouth bass, and provides important habitat for migratory waterfowl. The Great Lakes ecosystem is sensitive to nutrient pollution, making effective wastewater treatment critical for preventing algal blooms and maintaining water quality.