Plymouth WWTP - Secondary Treatment Plant in Cerro Gordo County, Iowa

Plymouth WWTP is a municipal wastewater treatment plant located in Cerro Gordo County, Iowa, United States. The facility serves a small population of 381 residents and is part of the region's wastewater infrastructure. The plant is situated in a rural area of north-central Iowa, reflecting the dispersed settlement pattern typical of the American Midwest. The plant provides secondary treatment, which is the standard level required by the US Clean Water Act for municipal wastewater facilities. Secondary treatment typically involves biological processes to remove organic matter and suspended solids. The plant has a designed capacity of 897.14 million gallons per year and currently discharges 162.77 million gallons per year, indicating it operates well below its capacity. The plant is regulated under the National Pollutant Discharge Elimination System (NPDES) permit program, administered by the Iowa Department of Natural Resources. The treated effluent from Plymouth WWTP is discharged into local waterways that ultimately drain into the Mississippi River basin. The plant's discharge contributes to the water quality of the region's streams and rivers, which support aquatic life and provide water for agricultural and recreational uses. The facility plays a key role in protecting downstream water bodies from untreated wastewater pollution.

The plant discharges into local streams that are part of the Upper Mississippi River basin. These waterways flow through agricultural landscapes and eventually reach the Mississippi River, which is a major ecological corridor supporting diverse fish and wildlife. The region's watershed is sensitive to nutrient pollution from agricultural runoff, and the plant's secondary treatment helps reduce organic and nutrient loads to protect downstream aquatic habitats.