Kirkwood STP - Secondary Wastewater Treatment Plant in Kirkwood, Illinois

Kirkwood STP is a municipal wastewater treatment facility located at 398 South Carr Street in Kirkwood, Illinois, a small community in Warren County. The plant serves a population of about 1,008 residents, placing it in the small-agglomeration category under US regulatory standards. The plant provides secondary treatment, the minimum level required by the US Clean Water Act for municipal wastewater facilities. With a designed capacity of 499.67 thousand gallons per day and a current discharge volume of 340.69 thousand gallons per day, the plant operates below its design capacity. As a US facility, it operates under a National Pollutant Discharge Elimination System (NPDES) permit issued by the Illinois Environmental Protection Agency, which sets effluent limits to protect water quality. The treated wastewater from Kirkwood STP discharges into a local stream that ultimately drains into the Mississippi River basin. The plant plays a key role in protecting downstream water quality in the region, supporting aquatic life and recreational uses in the receiving waters.

Kirkwood STP discharges into a tributary of the Mississippi River basin, which flows southward to the Gulf of Mexico. The local watershed supports diverse aquatic habitats and is part of a larger network of rivers and streams that provide critical ecosystem services. The plant's secondary treatment helps reduce nutrient loads and organic pollutants, mitigating the risk of eutrophication and oxygen depletion in downstream waters.