Harristown STP - Secondary Wastewater Treatment Plant in Harristown, Illinois

Harristown STP is a municipal wastewater treatment plant located in Harristown, Macon County, Illinois. Serving a population of 1,454, the plant provides secondary treatment to domestic wastewater from the community. The facility is situated in a rural area of central Illinois, where it manages an average daily flow of approximately 492,100 gallons. The plant employs secondary treatment processes, which involve biological treatment to reduce organic matter and suspended solids. With a designed capacity of 946,350 gallons per day, the facility operates well within its capacity, ensuring reliable treatment for the local population. As a US plant, it operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permits issued by the Illinois Environmental Protection Agency, which set effluent limits to protect water quality. Treated effluent from Harristown STP is discharged into nearby streams that flow into the Sangamon River, a tributary of the Illinois River, which ultimately drains into the Mississippi River. The plant plays a key role in protecting local water quality and the downstream aquatic ecosystem, supporting fish and wildlife habitats in the region.

The plant discharges into local streams that feed the Sangamon River, which flows into the Illinois River and then the Mississippi River. This watershed supports diverse aquatic life and is an important migratory corridor for birds and fish. The plant's secondary treatment helps reduce nutrient and organic pollution, protecting downstream water quality in the Mississippi River basin.