Oakville Lagoon Wastewater Treatment Plant, Louisa County, Iowa

Oakville Lagoon is a wastewater treatment facility located in Louisa County, Iowa, United States. It serves a small community of approximately 439 people, reflecting its role as a local-scale treatment plant in a rural agricultural region. The plant provides secondary treatment, which is the standard level required under the U.S. Clean Water Act for municipal wastewater facilities. With a designed capacity of 189.27 megaliters per year, the plant operates within its capacity to manage the community's wastewater. The facility is a lagoon system, a common treatment method for small populations in the Midwest. The treated effluent is discharged into nearby waterways that drain into the Mississippi River basin, ultimately reaching the Gulf of Mexico. This discharge contributes to the nutrient load in the watershed, which is a concern for downstream water quality and the Gulf's hypoxic zone. The plant's operation is regulated under the National Pollutant Discharge Elimination System (NPDES) to ensure compliance with environmental standards.

The plant discharges into local streams that are part of the Mississippi River watershed, which flows into the Gulf of Mexico. This region is agriculturally intensive, and nutrient runoff from both point and non-point sources contributes to the seasonal hypoxic zone in the Gulf. The plant's secondary treatment helps reduce organic pollutants, but nutrient removal may be limited, impacting downstream aquatic ecosystems.