MT PLEASANT MILLS STP - Perry Township, Pennsylvania Wastewater Treatment Plant

MT PLEASANT MILLS STP is a municipal wastewater treatment facility located in Perry Township, Snyder County, Pennsylvania. The plant serves a small population of 420 residents and operates under the regulatory framework of the US Clean Water Act, which requires secondary treatment for municipal facilities. As a small agglomeration, the plant is subject to National Pollutant Discharge Elimination System (NPDES) permits issued by the Pennsylvania Department of Environmental Protection, ensuring compliance with effluent limits. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. With a designed capacity of 189.27 units and an actual discharge volume of 151.42 units, the facility operates below its design capacity, indicating adequate headroom for current demand. Secondary treatment typically involves activated sludge or trickling filter systems. The treated effluent is discharged into a local water body, likely a stream or river within the Susquehanna River basin, which ultimately drains into the Chesapeake Bay. The plant's location inland and away from coastal areas reduces direct marine impact, but its discharge contributes to the nutrient load in the Chesapeake Bay watershed, a region of significant ecological concern due to eutrophication and habitat degradation.

The plant discharges into a local water body within the Susquehanna River basin, which flows into the Chesapeake Bay. The Chesapeake Bay is the largest estuary in the United States and supports diverse aquatic life, including blue crabs, oysters, and migratory fish. Nutrient pollution from wastewater treatment plants is a key concern in this watershed, as excess nitrogen and phosphorus can cause harmful algal blooms and hypoxia. The plant's secondary treatment helps reduce organic pollutants, but nutrient removal may be limited unless advanced treatment is employed.