Twin Lakes STP - Rockwell City, Iowa Wastewater Treatment Plant

Twin Lakes STP is a municipal wastewater treatment plant located in Rockwell City, Iowa, United States. It serves a small population of approximately 300 residents, reflecting its role in a rural community. The plant is situated in Calhoun County and operates under the regulatory framework of the US Clean Water Act. The plant provides secondary treatment, which is the standard level required for most municipal facilities under the National Pollutant Discharge Elimination System (NPDES). With a designed capacity of 227.12 volume units and a discharge volume of 227.13 volume units, the plant operates near its capacity, indicating consistent demand. Secondary treatment typically involves biological processes to reduce organic matter and suspended solids. The treated effluent is discharged into local water bodies that drain into the broader Mississippi River basin. This discharge contributes to the overall water quality management in the region, protecting downstream aquatic ecosystems. The plant's inland location reduces direct marine impact, but its operations are crucial for maintaining the health of local streams and rivers.

The plant discharges into local waterways that are part of the Mississippi River basin, ultimately draining into the Gulf of Mexico. This watershed supports diverse aquatic life and is important for regional agriculture and recreation. The plant's secondary treatment helps reduce nutrient loads, which is critical for mitigating downstream hypoxia in the Gulf.