Frannie Lagoon Wastewater Treatment Plant, Park County, Wyoming

Frannie Lagoon is a wastewater treatment facility located in Park County, Wyoming, United States. The plant serves a small population of 157 residents, reflecting its role as a lagoon-based system typical of rural communities in the region. The plant provides secondary treatment, which is the standard level required by the U.S. Clean Water Act for municipal wastewater. With a designed capacity of 75.71 megaliters and an annual discharge volume of 68.14 megaliters, the facility operates within its capacity. As a small agglomeration, it falls under state-level NPDES permitting oversight, ensuring compliance with effluent limits. The treated effluent from Frannie Lagoon is discharged into local waterways that ultimately drain into the Bighorn River basin, part of the larger Missouri River watershed. This region supports diverse aquatic life and agricultural activities, making proper treatment essential for protecting downstream water quality and ecosystem health.

Frannie Lagoon discharges into the Bighorn River basin, which flows into the Yellowstone River and then the Missouri River, eventually reaching the Gulf of Mexico. The surrounding area is semi-arid with agricultural land use, and the plant's secondary treatment helps protect local streams from nutrient pollution that could affect downstream aquatic habitats and irrigation water quality.