Marsing Sewage Lagoon - Secondary Wastewater Treatment in Marsing, Idaho

Marsing Sewage Lagoon serves the community of Marsing, Idaho, a small town in Owyhee County. The plant provides secondary treatment for a population of 1,307, typical for a small agglomeration in the United States. It operates under the regulatory framework of the US Clean Water Act, which requires secondary treatment for municipal wastewater discharges. The plant's designed capacity is 1,135.62 megaliters per year, with an actual discharge volume of 473.18 megaliters per year, indicating it operates below its capacity. As a lagoon system, it likely uses natural biological processes for treatment. The plant is located inland, more than 50 km from the coast, reducing direct marine impact. Treated effluent from the plant likely discharges into a local waterway that flows into the Snake River, a major tributary of the Columbia River. The Snake River supports diverse aquatic life and is an important migratory corridor for salmon and steelhead. The plant's operations are subject to National Pollutant Discharge Elimination System (NPDES) permits issued by the Idaho Department of Environmental Quality.

The plant's discharge likely enters a tributary of the Snake River, which flows into the Columbia River and ultimately the Pacific Ocean. The Snake River basin supports critical habitats for native fish species, including salmon and steelhead, which are sensitive to water quality. The plant's secondary treatment helps reduce organic pollutants and protect downstream aquatic ecosystems.