Le Grand STL Wastewater Treatment Plant, Le Grand, Iowa

Le Grand STL is a municipal wastewater treatment plant located in Le Grand, Iowa, serving a small population of 854 residents. The facility provides secondary treatment, a standard level for communities of this size in the United States. The plant has a designed capacity of 302.83 megaliters and discharges approximately 227.13 megaliters of treated effluent annually. As a U.S. facility, it operates under the Clean Water Act, with National Pollutant Discharge Elimination System (NPDES) permits issued by the Iowa Department of Natural Resources to regulate discharges and protect water quality. The treated effluent is discharged into local waterways that drain into the Iowa River basin, eventually reaching the Mississippi River and the Gulf of Mexico. The plant plays a key role in protecting downstream aquatic ecosystems from untreated wastewater pollution.

The plant discharges into the Iowa River watershed, which flows into the Mississippi River and ultimately the Gulf of Mexico. This region supports diverse aquatic life and is part of a major migratory corridor for birds and fish. The secondary treatment process reduces organic pollutants and suspended solids, helping to maintain water quality in the downstream river system.