Interior Township STP - Secondary Wastewater Treatment in Michigan's Upper Peninsula

Interior Township STP (Sewage Treatment Plant) serves the small community of Interior Township in Michigan's Upper Peninsula, located near Trout Creek. The plant provides secondary treatment for a population of 326, typical for a small rural agglomeration in the United States. As a secondary treatment facility, it meets the standard requirements under the U.S. Clean Water Act, which mandates secondary treatment for municipal wastewater plants. The plant's designed capacity is 264.98 thousand cubic meters per year, and it operates under the National Pollutant Discharge Elimination System (NPDES) permit program, administered by the Michigan Department of Environment, Great Lakes, and Energy (EGLE). The treated effluent is discharged into local surface waters, which ultimately drain into the Lake Superior basin. Lake Superior is the largest of the Great Lakes and supports diverse aquatic life, including cold-water fish species. The plant's operations help protect water quality in this ecologically sensitive region.

The plant discharges into local streams that flow into the Ontonagon River, which drains into Lake Superior. Lake Superior is a critical freshwater resource with oligotrophic conditions, supporting native fish like lake trout and whitefish. The surrounding watershed is forested and sparsely populated, making water quality protection important for recreational and ecological values.