State Center WWTP - Marshall County, Iowa Wastewater Treatment Plant

State Center WWTP is a municipal wastewater treatment facility located in Marshall County, Iowa, United States. The plant serves a population of 1,349 residents and is situated along Lincoln Highway in State Center Township. As a secondary treatment plant, it provides biological treatment to remove organic matter and suspended solids from wastewater. The plant has a designed capacity of 719.23 million gallons per year and currently discharges 643.52 million gallons annually. Under the U.S. Clean Water Act, facilities of this scale are required to obtain National Pollutant Discharge Elimination System (NPDES) permits, which set effluent limits to protect water quality. Secondary treatment is the minimum standard for municipal wastewater plants in the United States. The treated effluent from State Center WWTP is discharged into a local waterway that eventually drains into the Mississippi River Basin. The plant plays a key role in protecting downstream water quality and aquatic ecosystems in the region. Its operation supports the environmental health of Marshall County and contributes to the overall water quality goals of the state of Iowa.

The plant discharges into a local stream that flows into the Iowa River, a tributary of the Mississippi River. The Mississippi River Basin supports diverse aquatic life and is a critical migratory corridor for fish and birds. The plant's secondary treatment helps reduce nutrient and pollutant loads, protecting downstream water quality in this agriculturally intensive region.