Marysville STP - Wastewater Treatment Plant in St. Clair County, Michigan

Marysville STP is a municipal wastewater treatment facility located in St. Clair County, Michigan, serving a population of approximately 10,248. The plant is situated near the St. Clair River, a major waterway connecting Lake Huron to Lake St. Clair, and operates under the regulatory framework of the U.S. Clean Water Act, which requires National Pollutant Discharge Elimination System (NPDES) permits for all discharges. As a facility serving a medium-sized community, Marysville STP is expected to provide at least secondary treatment under federal standards. The plant has a designed capacity of 1.00 million gallons per day, indicating it is sized to handle the wastewater from its service area. Treatment processes typically include biological treatment followed by disinfection to meet permit limits for biochemical oxygen demand, total suspended solids, and other pollutants. The treated effluent from Marysville STP discharges into the St. Clair River, which flows southward into Lake St. Clair and then via the Detroit River to Lake Erie. This water body is part of the Great Lakes Basin, a critical freshwater resource supporting drinking water, recreation, and diverse aquatic life. The plant's discharge must comply with strict water quality standards to protect downstream ecosystems and human uses.

The St. Clair River is a connecting channel in the Great Lakes system, carrying water from Lake Huron to Lake St. Clair. This river supports a variety of fish species and is an important migratory corridor for aquatic life. Downstream, Lake St. Clair and the Detroit River lead to Lake Erie, which has experienced eutrophication issues from nutrient pollution. The plant's discharge must be carefully managed to prevent excess nutrients and contaminants from impacting these sensitive waters.