Mondamin STL Wastewater Treatment Plant, Harrison County, Iowa

Mondamin STL is a municipal wastewater treatment plant located in Harrison County, Iowa, United States. The facility serves a small population of 423 residents, providing secondary treatment to meet state and federal water quality standards. The plant has a designed capacity of 189.27 cubic meters per day and currently treats a daily volume of 113.56 cubic meters. As a secondary treatment facility, it uses biological processes to reduce organic matter and suspended solids, in compliance with the U.S. Clean Water Act and National Pollutant Discharge Elimination System (NPDES) permit requirements. The treated effluent is discharged into a local water body that drains into the Missouri River watershed. This river system supports diverse aquatic life and provides water for agricultural and recreational uses downstream. Proper treatment at Mondamin STL helps protect water quality in the region.

The plant discharges into a tributary of the Missouri River, which flows into the Mississippi River and ultimately the Gulf of Mexico. The Missouri River basin supports important fish habitats and migratory bird corridors. Effective wastewater treatment is essential to prevent nutrient pollution and maintain ecological balance in this large river system.