Cambridge STL Wastewater Treatment Plant - Cambridge, Iowa

Cambridge STL is a municipal wastewater treatment facility located in Cambridge, Iowa, along the Heart of Iowa Nature Trail. The plant serves a small population of 920 residents in this rural community within Story County. The plant provides secondary treatment, which is the standard biological treatment process required under the U.S. Clean Water Act for municipal wastewater. With a designed capacity of 605.66 volume units and an average daily discharge of 310.40 volume units, the facility operates below its capacity, indicating room for future growth. The treated effluent is discharged into local waterways that ultimately drain into the Mississippi River basin. The plant plays a key role in protecting downstream water quality in the region's agricultural landscape, supporting aquatic life and recreational uses in receiving streams.

The plant discharges into tributaries of the South Skunk River, which flows into the Iowa River and then the Mississippi River. The surrounding watershed is primarily agricultural, with row crops and livestock operations. The plant's secondary treatment helps reduce nutrient loads and organic pollutants, protecting downstream aquatic ecosystems and drinking water sources.