Thorn Creek Basin SD STP - Chicago Heights, Illinois Wastewater Treatment Plant

Thorn Creek Basin SD STP is a municipal wastewater treatment plant located in Chicago Heights, Illinois, serving a population of approximately 91,505. The facility is situated in Cook County and is part of the region's water infrastructure. As a medium-to-large agglomeration, the plant is expected to meet secondary treatment standards under the U. S. Clean Water Act, with NPDES permits issued by the Illinois Environmental Protection Agency. The designed capacity is 1.00 million gallons per day, indicating a facility sized for its service area. The plant discharges treated effluent into the Thorn Creek watershed, which flows into the Little Calumet River and ultimately into Lake Michigan. This water body supports diverse aquatic life and provides drinking water for millions in the Great Lakes region.

The plant discharges into Thorn Creek, a tributary of the Little Calumet River, which drains into Lake Michigan. Lake Michigan is a major freshwater resource supporting fisheries, recreation, and municipal water supply. The watershed is ecologically sensitive, with efforts to reduce nutrient loading and protect aquatic habitats.