Grattan STP - Secondary Wastewater Treatment in Grattan Township, Michigan

Grattan STP is a municipal wastewater treatment facility located in Grattan Township, Kent County, Michigan. The plant serves a population of approximately 3,551 residents, classifying it as a small to medium-sized facility within the state's wastewater infrastructure. The plant provides secondary treatment, which is the standard level required under the U.S. Clean Water Act for municipal wastewater facilities. With a designed capacity of 681.37 thousand gallons per day and an average discharge volume of 567.81 thousand gallons per day, the plant operates below its design capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into local waterways that ultimately drain into the Grand River watershed and then into Lake Michigan. The plant plays a crucial role in protecting the water quality of the Grand River basin and the downstream Great Lakes ecosystem, supporting aquatic life and recreational uses.

The plant discharges into the Grand River watershed, which flows into Lake Michigan, part of the Great Lakes system. The Grand River is the longest river in Michigan and supports diverse aquatic species, including fish and macroinvertebrates. The plant's secondary treatment helps reduce nutrient and organic pollutant loads, protecting downstream water quality and the ecological health of Lake Michigan.