Unionville STP - Secondary Wastewater Treatment in Columbia Township, Michigan

Unionville STP is a municipal wastewater treatment plant located in Columbia Township, Tuscola County, Michigan. It serves a small population of 574 residents, reflecting its role in a rural community within the Great Lakes region. The plant provides secondary treatment, a standard level for small agglomerations in the United States. Under the Clean Water Act, such facilities must meet National Pollutant Discharge Elimination System (NPDES) permit requirements to control pollutant discharges. The plant's designed capacity is 340.69 cubic meters per day, with a current discharge volume of 189.27 cubic meters per day. The treated effluent is discharged into local waterways that ultimately drain into Lake Huron, one of the Great Lakes. This watershed supports diverse aquatic life and provides drinking water for millions. The plant's coastal proximity (within 10 km of the lake) underscores the importance of effective treatment to protect the sensitive Great Lakes ecosystem.

The plant discharges into tributaries of the Saginaw Bay, part of the Lake Huron basin. Lake Huron is a critical freshwater resource supporting fisheries, recreation, and biodiversity. The coastal location requires careful management to prevent nutrient loading and algal blooms, which can impact water quality in the Great Lakes.