Cincinnati STL Wastewater Treatment Plant, Cincinnati, Iowa

Cincinnati STL is a municipal wastewater treatment plant located in Cincinnati, Appanoose County, Iowa, United States. The facility serves a small population of approximately 363 residents, reflecting its role in a rural community. As a secondary treatment plant, it provides biological treatment to reduce organic matter and suspended solids before discharge. The plant operates under the U.S. Clean Water Act, which requires National Pollutant Discharge Elimination System (NPDES) permits for all point source discharges. For small communities like Cincinnati, secondary treatment is the standard requirement to protect water quality. The plant's designed capacity is 264.98 thousand cubic meters per year, matching its current discharge volume, indicating full utilization. The treated effluent is discharged into local streams that drain into the Chariton River basin, part of the Mississippi River watershed. The receiving waters support aquatic life and are used for recreation and agriculture downstream. Proper treatment helps maintain water quality in this rural Iowa landscape.

The plant discharges into local waterways within the Chariton River basin, which flows into the Des Moines River and ultimately the Mississippi River. This watershed supports diverse aquatic habitats and is important for regional biodiversity. The secondary treatment process reduces nutrient and organic loads, helping to protect downstream water quality in a region dominated by agricultural land use.