Goldfield STL Wastewater Treatment Plant, Goldfield, Iowa

Goldfield STL is a municipal wastewater treatment facility located on 220th Street in Goldfield, Wright County, Iowa. The plant serves a small population of 710 residents, typical of rural communities in the Midwestern United States. Its location in the agricultural heartland places it within a network of small-scale treatment systems that manage domestic wastewater for dispersed populations. The plant provides secondary treatment, which is the standard required by the US Clean Water Act for municipal facilities of this size. Secondary treatment uses biological processes to remove organic matter and suspended solids, producing effluent suitable for discharge into surface waters. The plant's designed capacity is 302.83 megaliters, and it currently treats 227.13 megaliters annually, indicating operational headroom. Treated effluent from Goldfield STL is discharged into local waterways that ultimately drain into the Mississippi River basin. The plant plays a key role in protecting downstream water quality in Iowa's prairie streams and rivers, which support diverse aquatic life and are used for recreation and agriculture. Compliance with NPDES permits ensures that nutrient and pathogen levels remain within safe limits for the receiving environment.

Goldfield STL discharges into tributaries of the Iowa River, which flows into the Mississippi River and eventually the Gulf of Mexico. The local watershed is dominated by agricultural land use, making nutrient management critical to prevent downstream eutrophication. The plant's secondary treatment helps reduce organic loads and suspended solids, supporting aquatic habitat in the region's prairie streams.