Corwith Lagoon Wastewater Treatment Plant, Corwith, Iowa

Corwith Lagoon is a municipal wastewater treatment facility located in Corwith, Hancock County, Iowa, United States. The plant serves a small population of 350 residents, reflecting its role in a rural community. It is situated on 160th Street, within the state's agricultural landscape. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. With a designed capacity of 991.77 units and a discharge volume of 401.25 units, the facility operates well within its capacity. As a US plant serving fewer than 10,000 people, it falls under the Clean Water Act's National Pollutant Discharge Elimination System (NPDES) permitting framework, which sets effluent limits to protect water quality. The treated effluent is discharged into a local water body, ultimately contributing to the Mississippi River basin via the Iowa River system. This watershed supports diverse aquatic life and is important for regional agriculture and recreation. The plant's operation helps maintain the ecological health of downstream waters.

The plant discharges into a local watercourse that drains into the Iowa River, a tributary of the Mississippi River. The Mississippi River basin is a major ecological corridor supporting diverse fish, bird, and plant species. Downstream waters are used for recreation and agriculture, making nutrient and pathogen control critical. The plant's secondary treatment reduces organic pollution, protecting aquatic habitats.