Williamson WWTP - Secondary Treatment Plant in Lucas County, Iowa

Williamson WWTP is a municipal wastewater treatment plant located on 540th Street in Lucas County, Iowa, serving a small population of 146 residents. The facility provides secondary treatment, a standard level for small communities in the United States. The plant has a designed capacity of 64.35 million gallons per day, matching its current discharge volume, indicating full utilization. As a U.S. facility, it operates under the Clean Water Act's National Pollutant Discharge Elimination System (NPDES) permit program, which sets effluent limits to protect water quality. The treated effluent is discharged into local waterways that drain into the Mississippi River basin, ultimately reaching the Gulf of Mexico. The plant plays a role in protecting downstream aquatic ecosystems from nutrient pollution and pathogens.

The plant discharges into streams within the Mississippi River basin, which flows into the Gulf of Mexico. This region is part of the Mississippi River watershed, a critical ecological corridor supporting diverse aquatic life and migratory birds. Nutrient loading from wastewater can contribute to hypoxia in the Gulf, making effective treatment important for downstream water quality.