Halliday Lagoon Wastewater Treatment Plant, Halliday, North Dakota

Halliday Lagoon is a municipal wastewater treatment facility located in Halliday, North Dakota, a small community in Dunn County. The plant serves a population of 188 residents, reflecting its role as a local infrastructure asset for this rural area. The plant provides secondary treatment, which is the standard biological treatment stage required under the U.S. Clean Water Act for municipal wastewater. With a designed capacity of 75.71 cubic meters per day and a matching discharge volume, the facility operates at full capacity. As a small system, it is subject to state-level NPDES permitting through the North Dakota Department of Environmental Quality. The treated effluent is discharged into a local watercourse that drains into the Missouri River watershed, ultimately reaching the Gulf of Mexico. The plant's location more than 10 km from the coast reduces direct marine impact, but its discharge contributes to the overall nutrient load in the Missouri River basin, which is a concern for downstream water quality and aquatic ecosystems.

The plant discharges into a tributary of the Missouri River, which flows into the Mississippi River and then the Gulf of Mexico. The Missouri River basin supports diverse aquatic life and is a critical migratory corridor for birds. Nutrient loading from wastewater can contribute to hypoxic zones in the Gulf, making treatment performance important for downstream ecosystem health.