Lyons SD 2 WWTP - Advanced Wastewater Treatment in Town of Lyons, Wisconsin

Lyons SD 2 WWTP is a municipal wastewater treatment facility located in the Town of Lyons, Walworth County, Wisconsin. The plant serves a population of approximately 2,335 residents and operates under the regulatory framework of the US Clean Water Act, which requires National Pollutant Discharge Elimination System (NPDES) permits for all discharges to surface waters. The plant provides advanced treatment, which goes beyond secondary treatment to remove additional nutrients such as nitrogen and phosphorus. With a designed capacity of 832.79 m³/day and an actual discharge volume of 378.54 m³/day, the facility operates well below its capacity, indicating room for future growth. Advanced treatment typically involves biological nutrient removal or tertiary filtration. The treated effluent is discharged into a local water body that ultimately drains into the Fox River basin, which flows into the Illinois River and then the Mississippi River. This downstream chain connects to the Gulf of Mexico, making nutrient removal important for reducing hypoxia in the Gulf. The plant's location in southeastern Wisconsin places it in a region with mixed agricultural and residential land use.

The plant discharges into a tributary of the Fox River, which flows into the Illinois River and then the Mississippi River, eventually reaching the Gulf of Mexico. This watershed is part of the Mississippi River Basin, which is ecologically significant for its role in nutrient transport and the seasonal hypoxic zone in the Gulf. The advanced treatment helps reduce nutrient loading, protecting downstream aquatic ecosystems and supporting water quality goals.