ANDALUSIA STP - Secondary Wastewater Treatment Plant in Andalusia, Illinois

ANDALUSIA STP is a municipal wastewater treatment plant located in Andalusia, Illinois, United States. The facility serves a population of approximately 1,178 residents in the Rock Island County area. As a secondary treatment plant, it provides biological treatment to reduce organic pollutants and suspended solids before discharge. The plant operates under the U.S. Clean Water Act, which requires secondary treatment for municipal wastewater. The National Pollutant Discharge Elimination System (NPDES) permit program, administered by the Illinois Environmental Protection Agency, governs its discharge. The plant has a designed capacity of 832.79 megaliters per year and currently treats an annual volume of 378.54 megaliters. The treated effluent is discharged into a local waterway that ultimately drains into the Mississippi River basin. The Mississippi River is a major ecological corridor supporting diverse aquatic life and migratory birds. The plant's location inland, away from coastal areas, reduces direct marine impact, but its discharge contributes to the overall water quality of the Mississippi River system.

The plant discharges into a tributary of the Mississippi River, which flows southward to the Gulf of Mexico. The Mississippi River basin is one of the largest in North America, supporting a wide range of aquatic species and providing critical habitat for migratory waterfowl. The plant's secondary treatment helps protect downstream water quality in this ecologically significant river system.