ONEIDA NORTH LAGOON Wastewater Treatment Plant, Knox County, Illinois

ONEIDA NORTH LAGOON is a municipal wastewater treatment facility located on Knox Highway 3 in Knox County, Illinois, serving a small population of 465 residents. The plant operates as part of the region's rural wastewater infrastructure, providing essential sanitation services to the community. The facility provides secondary treatment, which is the standard level required by the US Clean Water Act for municipal plants of this scale. With a designed capacity of 454.25 volume units and an average discharge volume of 264.98, the plant operates well within its capacity. Treatment processes typical for small lagoon systems in Illinois include stabilization ponds or aerated lagoons, which effectively reduce organic pollutants and suspended solids before discharge. The treated effluent from ONEIDA NORTH LAGOON is discharged into local streams that drain into the Illinois River basin, ultimately reaching the Mississippi River. This watershed supports diverse aquatic life and provides habitat for fish and migratory birds. The plant's compliance with National Pollutant Discharge Elimination System (NPDES) permits ensures that its discharge meets water quality standards to protect downstream ecosystems.

The plant discharges into tributaries of the Illinois River, which flows into the Mississippi River, a major waterway supporting extensive ecological networks. The local watershed includes agricultural and rural areas, where nutrient management is critical to prevent eutrophication in downstream waters. The Illinois River basin provides habitat for numerous fish species and migratory waterfowl, making water quality protection essential for regional biodiversity.