DANVILLE STW Wastewater Treatment Plant, Danville, Illinois

DANVILLE STW is a municipal wastewater treatment plant located in Danville, Illinois, serving a population of approximately 57,056. The facility is situated in Vermilion County and operates under the regulatory framework of the United States Clean Water Act, which requires National Pollutant Discharge Elimination System (NPDES) permits for all point source discharges. As a medium-sized agglomeration, the plant is expected to meet secondary treatment standards as defined by the EPA, ensuring removal of organic matter and suspended solids. However, under the Clean Water Act, facilities of this scale typically employ secondary treatment processes such as activated sludge or trickling filters to comply with effluent limitations. The plant's discharge is regulated by an NPDES permit issued by the Illinois Environmental Protection Agency, which sets specific limits on pollutants to protect water quality. The treated effluent from DANVILLE STW is discharged into the Vermilion River, a tributary of the Wabash River, which flows southward to join the Ohio River. This watershed supports diverse aquatic life and provides recreational and ecological value. The plant's operation is critical to maintaining water quality in the Vermilion River and downstream ecosystems, including the Wabash and Ohio Rivers.

The plant discharges into the Vermilion River, which flows into the Wabash River, a major tributary of the Ohio River. The Wabash River watershed supports diverse aquatic habitats, including fish and mussel species, and is an important migratory corridor for birds. The Ohio River ultimately drains to the Mississippi River and the Gulf of Mexico, making the plant's effluent quality significant for downstream water quality across multiple states.