MERRILL STP Wastewater Treatment Plant, Merrill, Wisconsin

MERRILL STP is a municipal wastewater treatment plant located at 2621 Sturdevant Street in Merrill, Lincoln County, Wisconsin. It serves a population of 9,614, classifying it as a small to medium agglomeration under US regulatory frameworks. As a US facility, MERRILL STP operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permitting. For plants serving around 10,000 people, secondary treatment is typically required, with additional nutrient controls in sensitive watersheds. Regulatory standards ensure compliance with effluent limits. The plant discharges into the Wisconsin River basin, which flows southward through central Wisconsin and eventually joins the Mississippi River near Prairie du Chien. The Wisconsin River supports diverse aquatic life and is an important recreational and ecological corridor in the region.

MERRILL STP discharges into the Wisconsin River, a major tributary of the Mississippi River. The Wisconsin River watershed encompasses diverse habitats, including forests and wetlands, and supports fish species such as walleye and smallmouth bass. Downstream, the Mississippi River provides critical migratory pathways for birds and aquatic species. The plant's location in central Wisconsin places it within a region where nutrient management is important to prevent algal blooms in downstream waters.