Malcom STL Wastewater Treatment Plant, Malcom, Iowa

Malcom STL is a municipal wastewater treatment plant located in Malcom, Iowa, a small community in Poweshiek County. The facility serves a population of 287, classifying it as a small-scale treatment operation within the state's wastewater infrastructure. The plant provides secondary treatment, which is the standard level required by the U.S. Clean Water Act for municipal facilities discharging to surface waters. Secondary treatment typically involves biological processes to reduce organic matter and suspended solids. The plant's designed capacity is 302.83 units, and it treats an average daily flow of 416.40 units, indicating operation above its nominal capacity. The treated effluent is discharged into local waterways that drain into the Iowa River basin, ultimately reaching the Mississippi River. This discharge contributes to the overall water quality management in the region, supporting aquatic life and downstream uses. The plant's performance is regulated under the National Pollutant Discharge Elimination System (NPDES) permit program administered by the Iowa Department of Natural Resources.

The plant discharges into a tributary of the Iowa River, which flows into the Mississippi River. This watershed supports diverse aquatic habitats and is part of the larger Mississippi River basin, a critical ecological corridor for migratory fish and waterfowl. The receiving waters are sensitive to nutrient loading, making effective secondary treatment important for maintaining water quality.