GILBERT STL Wastewater Treatment Plant, Gilbert, Iowa

GILBERT STL is a municipal wastewater treatment plant located in Gilbert, Iowa, United States. The facility serves a population of approximately 796 residents, classifying it as a small-scale treatment operation within the state's wastewater infrastructure. The plant employs secondary treatment processes, which is the standard level required by the U.S. Clean Water Act for municipal wastewater treatment. With a designed capacity of 492.10 megaliters and an annual discharge volume of 227.13 megaliters, the facility operates well within its capacity. As a U.S. plant, it operates under the National Pollutant Discharge Elimination System (NPDES) permit program, administered by the Iowa Department of Natural Resources, ensuring compliance with effluent limits. The treated effluent is discharged into local waterways that ultimately drain into the Mississippi River basin. The plant's location in central Iowa places it within an agricultural region, where maintaining water quality is important for both ecological health and downstream uses. The facility contributes to protecting local streams and rivers from nutrient pollution and other contaminants.

The plant discharges into receiving waters that flow through the Skunk River watershed, part of the larger Mississippi River basin. This region supports diverse aquatic life and is an important corridor for migratory birds. The downstream environment includes agricultural runoff concerns, making the plant's nutrient removal role critical for preventing eutrophication in local water bodies.