GREELEY STL Wastewater Treatment Plant, Delaware County, Iowa

GREELEY STL is a municipal wastewater treatment plant located in Delaware County, Iowa, United States. The facility serves a small population of 263 residents, reflecting its role in a rural community within the state's agricultural landscape. 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 189.27 megaliters and an annual discharge volume of 113.56 megaliters, the plant operates well within its capacity. As a small facility, it is subject to state-level NPDES permitting through the Iowa Department of Natural Resources. The treated effluent is discharged into local waterways that drain into the Mississippi River basin, ultimately reaching the Gulf of Mexico. The plant's operations help protect downstream water quality in a region dominated by agriculture, where nutrient management is a key environmental concern.

The plant discharges into tributaries of the Mississippi River, which flows into the Gulf of Mexico. This region is part of the Upper Mississippi River basin, an area known for agricultural runoff that contributes to nutrient loading. The plant's secondary treatment helps reduce organic pollutants and suspended solids, supporting the ecological health of downstream waters.