Deerfield STP - Advanced Wastewater Treatment Plant in Deerfield, Wisconsin

Deerfield STP is a municipal wastewater treatment facility located at 145 North Industrial Park Road in Deerfield, Dane County, Wisconsin. The plant serves a population of approximately 2,053 people, reflecting its role as a small community treatment system within the state's wastewater infrastructure. The facility employs advanced treatment processes, which go beyond standard secondary treatment to remove nutrients and other pollutants. With a designed capacity of 1,487.66 thousand cubic meters per year and an actual discharge volume of 518.60 thousand cubic meters per year, the plant operates well within its capacity. As a US facility, it operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permitting, which sets effluent limits to protect water quality. The plant's treated effluent is discharged into local streams that flow into the Yahara River, a key waterway in southern Wisconsin. The Yahara River drains into the Rock River, which ultimately reaches the Mississippi River. This connection places the plant within a larger watershed that supports diverse aquatic life and provides drinking water for downstream communities. The advanced treatment helps minimize nutrient loading, reducing the risk of algal blooms in downstream lakes and rivers.

The plant discharges into tributaries of the Yahara River, which flows through a chain of lakes in Dane County before joining the Rock River. The Rock River is a major tributary of the Mississippi River, one of the largest river systems in North America. The Yahara watershed supports diverse aquatic habitats, including wetlands and fisheries, and is important for regional biodiversity. Advanced treatment at the plant helps protect these ecosystems from nutrient pollution and other contaminants.