Bloomington Normal West Old STP - Wastewater Treatment in Bloomington, Illinois

Bloomington Normal West Old STP is a wastewater treatment facility located on Fox Creek Road in Bloomington, McLean County, Illinois. It serves an estimated population of 124,377, making it a large agglomeration under US regulatory standards. The plant is part of the broader wastewater infrastructure serving the Bloomington-Normal metropolitan area. As a US facility serving over 100,000 people, the plant operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permitting. The US Environmental Protection Agency (EPA) and the Illinois Environmental Protection Agency oversee compliance. For plants of this scale, secondary treatment is the minimum standard, with nutrient removal often required to protect downstream water quality. The plant discharges treated effluent into local waterways that ultimately drain into the Mississippi River basin. The receiving waters support aquatic life and are part of the larger Illinois River watershed, which flows into the Mississippi River and eventually the Gulf of Mexico. Protecting these waters is critical for regional ecosystems and downstream communities.

The plant's treated effluent enters local streams within the Mississippi River basin, flowing into the Illinois River and eventually the Gulf of Mexico. The downstream environment includes diverse aquatic habitats and supports migratory fish species. Nutrient loading from wastewater can contribute to hypoxic zones in the Gulf, making effective treatment important for regional water quality.