SULLIVAN STP - Wastewater Treatment Plant in Sullivan, Illinois

SULLIVAN STP is a wastewater treatment plant located on Patterson Road in Sullivan, Illinois, serving a population of about 4,334. The facility is situated in Moultrie County and operates under the regulatory framework of the United States Clean Water Act, which requires National Pollutant Discharge Elimination System (NPDES) permits for discharges into surface waters. As a small to medium-sized agglomeration, the plant is expected to provide at least secondary treatment under federal guidelines. The plant's scale suggests it likely employs conventional treatment technologies such as activated sludge or lagoon systems, common for communities of this size in the Midwest. The treated effluent from SULLIVAN STP ultimately discharges into the Kaskaskia River basin, which flows southwest through Illinois and empties into the Mississippi River. This watershed supports diverse aquatic life and is an important resource for regional agriculture and recreation. The plant's operations contribute to protecting local water quality in the Kaskaskia River system.

SULLIVAN STP discharges into the Kaskaskia River watershed, which drains into the Mississippi River and eventually the Gulf of Mexico. The Kaskaskia River supports a variety of fish and wildlife species, including several state-listed species of concern. The plant's location in an agricultural region means its nutrient removal performance is important for downstream water quality, particularly in the context of the Gulf of Mexico hypoxic zone.