AVON STP Wastewater Treatment Plant, Fulton County, Illinois

AVON STP is a municipal wastewater treatment plant located in Fulton County, Illinois, United States. The facility serves a small population of 939 residents, providing secondary treatment to meet state and federal water quality standards. The plant operates with a designed capacity of 832.79 units and currently treats a daily flow of 416.40 units, indicating it operates well below its maximum capacity. As a secondary treatment facility, it employs biological processes to remove organic matter and suspended solids, complying with the U.S. Clean Water Act requirements for such facilities. The treated effluent is discharged into local waterways that ultimately drain into the Illinois River basin, contributing to the Mississippi River watershed. The plant plays a key role in protecting downstream aquatic ecosystems and maintaining water quality in the region's agricultural and rural landscape.

The plant discharges into tributaries of the Illinois River, which flows into the Mississippi River and eventually the Gulf of Mexico. The downstream environment supports diverse aquatic life and is part of a major migratory corridor for birds and fish. The plant's secondary treatment helps reduce nutrient loading, which is critical for mitigating hypoxia in the Gulf of Mexico.