Sheridan SD WWTP - Secondary Treatment Plant in LaSalle County, Illinois

Sheridan SD WWTP is a municipal wastewater treatment facility located in Mission Township, LaSalle County, Illinois, United States. The plant serves a small population of 846 residents and operates under secondary treatment standards, which are typical for smaller communities in the region. The plant's designed capacity is 1393.03 thousand cubic meters, and it currently discharges 946.35 thousand cubic meters of treated effluent annually. As a secondary treatment facility, it meets the minimum requirements under the U.S. Clean Water Act for removing organic matter and suspended solids before discharge. The treated wastewater is discharged into local waterways that ultimately drain into the Illinois River basin, a major tributary of the Mississippi River. This connection to the larger Mississippi River system underscores the plant's role in protecting downstream water quality and aquatic ecosystems.

The plant discharges into local streams that flow into the Illinois River, which joins the Mississippi River and eventually reaches the Gulf of Mexico. This watershed supports diverse aquatic life and provides habitat for migratory fish species. The plant's secondary treatment helps reduce nutrient loads that could contribute to hypoxia in the Gulf.