Forreston STP - Secondary Wastewater Treatment Plant in Forreston, Illinois

Forreston STP is a municipal wastewater treatment facility located in Forreston, Illinois, serving a population of approximately 1,446 residents. The plant is situated in Ogle County, part of the rural landscape of northern Illinois, and provides essential sanitation services to the community. The plant operates at the secondary treatment level, which is the standard requirement under the US Clean Water Act for municipal facilities of this scale. With a designed capacity of 1,135.62 thousand cubic meters and an actual discharge volume of 681.37 thousand cubic meters, the plant maintains a utilization rate that indicates operational headroom. The facility is regulated under the National Pollutant Discharge Elimination System (NPDES) permit program, administered by the Illinois Environmental Protection Agency. The treated effluent from Forreston STP is discharged into local waterways that ultimately drain into the Rock River basin, a tributary of the Mississippi River. The plant's operations help protect downstream aquatic ecosystems and maintain water quality in the region's surface waters, supporting both ecological health and recreational uses.

Forreston STP discharges into receiving waters that flow into the Rock River, a major tributary of the Mississippi River. The Rock River watershed supports diverse aquatic life, including fish species such as walleye and smallmouth bass, and provides habitat for migratory waterfowl. The plant's secondary treatment reduces organic pollutants and suspended solids, helping to maintain the ecological integrity of the downstream river system and the broader Mississippi River basin.