DELHI STL Wastewater Treatment Plant, Delaware County, Iowa

DELHI STL is a municipal wastewater treatment plant located in Delaware County, Iowa, United States. It serves a small community with a population of approximately 485 residents, reflecting its role in managing local domestic wastewater. The plant is situated in a rural area, typical of many small-scale facilities in the Midwest. The plant operates at the secondary treatment level, which is the standard requirement under the U.S. Clean Water Act for municipal wastewater treatment. Secondary treatment typically involves biological processes to remove organic matter and suspended solids. The plant has a designed capacity of 264.98 megaliters per year and currently discharges 151.42 megaliters annually, indicating it operates below its full capacity. The treated effluent is discharged into local water bodies, contributing to the protection of downstream ecosystems. As part of the Mississippi River basin, the plant's discharge ultimately flows into the Mississippi River, which supports diverse aquatic life and provides water for communities and industries. The plant's operation helps maintain water quality in this important watershed.

The plant discharges into local streams that are part of the Upper Mississippi River basin. The Mississippi River is a major ecological corridor supporting diverse fish and bird species. Downstream, the river flows into the Gulf of Mexico, where nutrient pollution from wastewater and agriculture contributes to seasonal hypoxic zones. The plant's secondary treatment helps reduce organic pollutants but does not specifically target nutrients like nitrogen and phosphorus.