Lancaster STP Wastewater Treatment Plant, Lancaster, Wisconsin

Lancaster STP is a municipal wastewater treatment plant located in Lancaster, Grant County, Wisconsin, serving a population of about 3,868. The facility is situated inland, more than 50 km from the coast, and operates under the regulatory framework of the U.S. Clean Water Act, which requires National Pollutant Discharge Elimination System (NPDES) permits for all discharges to surface waters. As a small agglomeration, the plant is expected to provide at least secondary treatment to meet water quality standards. Typical facilities of this scale in Wisconsin employ activated sludge or lagoon systems to achieve secondary treatment. The plant is subject to state and federal regulations that mandate effluent limits based on the receiving water body's designated uses. The treated effluent from Lancaster STP likely discharges into a tributary of the Grant River or directly into the Grant River, which flows into the Mississippi River. The Mississippi River basin supports diverse aquatic life and is a critical migratory corridor for birds and fish. The plant's operations contribute to protecting downstream water quality in this ecologically significant watershed.

Lancaster STP discharges into the Grant River watershed, which is part of the larger Mississippi River basin. The Grant River flows southward to join the Mississippi River near the Illinois border. The Mississippi River is a major ecological corridor supporting diverse fish species, migratory birds, and aquatic habitats. The plant's effluent must meet water quality standards to protect these downstream ecosystems, including nutrient limits to prevent eutrophication in the Mississippi River and the Gulf of Mexico.