Melba STP - Secondary Wastewater Treatment Plant in Melba, Idaho

Melba STP is a municipal wastewater treatment facility located on Baseline Road in Melba, Canyon County, Idaho. The plant serves a small population of 513 residents, reflecting the rural character of the community. As a secondary treatment plant, it provides biological treatment to reduce organic pollutants and suspended solids before discharge. The plant's designed capacity is 276.33 megaliters per year, and it currently discharges 151.42 megaliters per year, indicating operational headroom. Under the U.S. Clean Water Act, secondary treatment is the minimum standard for municipal wastewater plants, and the facility operates under an EPA NPDES permit issued by the Idaho Department of Environmental Quality, ensuring compliance with water quality standards. The treated effluent is discharged into the local watershed, which ultimately drains into the Snake River basin. The Snake River flows through southern Idaho and joins the Columbia River, which reaches the Pacific Ocean. The plant's discharge supports the health of downstream aquatic ecosystems, including fish habitats and irrigation water supplies in the arid region.

Melba STP discharges into the Snake River basin, a major tributary of the Columbia River that flows to the Pacific Ocean. The local watershed supports agricultural irrigation and provides habitat for native fish species, including salmon and steelhead in the larger Columbia system. The plant's secondary treatment helps protect downstream water quality in this semi-arid region.