Cass City STP - Elkland Township, Michigan Wastewater Treatment Plant

Cass City STP is a municipal wastewater treatment plant located in Elkland Township, Tuscola County, Michigan. It serves a population of approximately 2,643 residents, classifying it as a small community facility within the state's wastewater infrastructure. As a US-based plant, Cass City STP operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permits issued by the Michigan Department of Environment, Great Lakes, and Energy (EGLE). For small agglomerations like this, secondary treatment is typically required to meet effluent limits for biochemical oxygen demand and total suspended solids. The plant discharges treated wastewater into the local watershed, which ultimately drains into the Saginaw Bay of Lake Huron. This region is part of the Great Lakes Basin, an ecologically sensitive freshwater system that supports diverse aquatic life and provides drinking water for millions. Proper treatment is essential to protect water quality in the bay and downstream ecosystems.

The treated effluent from Cass City STP flows into the Cass River, a tributary of the Saginaw River, which empties into Saginaw Bay on Lake Huron. This area is part of the Great Lakes Basin, the largest freshwater system in the world. The bay supports important fish habitats and migratory bird routes, making nutrient and pollutant control critical to prevent algal blooms and maintain ecosystem health.