Overview
Post Falls Area STP serves 34,400 people in Post Falls, Idaho. The plant discharges treated wastewater into the Spokane River watershed, which flows to the Columbia River and ultimately the Pacific Ocean.
The Post Falls Area STP is a municipal wastewater treatment facility serving the city of Post Falls, Idaho, in Kootenai County. With a population served of 34,400, it is classified as a medium-sized agglomeration under U.S. regulatory frameworks. The plant is situated near the Spokane River, a key waterway in the region. As a U.S. facility, the plant operates under the Clean Water Act and is subject to National Pollutant Discharge Elimination System (NPDES) permits issued by the Idaho Department of Environmental Quality. For a plant of this scale, secondary treatment is typically required, and permits specify effluent limits to protect water quality. Standard practices for similar facilities include activated sludge or lagoon systems. The plant's treated effluent is discharged into the Spokane River, which flows westward into the Columbia River, the largest river in the Pacific Northwest. The Columbia River drains into the Pacific Ocean, supporting diverse aquatic life including salmon and steelhead. The Spokane River itself is an important recreational and ecological resource, with sensitive aquatic habitats downstream.
Environmental context
The Post Falls Area STP discharges into the Spokane River, a tributary of the Columbia River, which flows to the Pacific Ocean. The Spokane River supports a variety of fish species, including native redband trout and white sturgeon, and is a key corridor for migratory salmon. The watershed is ecologically sensitive due to urban runoff and industrial legacy, requiring careful management of nutrient and pollutant loads to maintain water quality and aquatic health.
Frequently asked questions
Post Falls Area STP is located in Post Falls, Idaho, United States, near the Spokane River in Kootenai County.
The plant serves approximately 34,400 people, classifying it as a medium-sized municipal wastewater treatment facility.
The plant discharges treated effluent into the Spokane River, which flows into the Columbia River and eventually reaches the Pacific Ocean.
As a U.S. facility, it operates under the Clean Water Act and is regulated via an NPDES permit issued by the Idaho Department of Environmental Quality, which sets effluent limits for pollutants.
For a plant of this size, secondary treatment is standard, often using activated sludge or trickling filter processes, with disinfection to meet permit requirements.
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