Overview
COLFAX STP is a municipal wastewater treatment plant serving approximately 2,845 residents in Colfax, Washington, United States. It operates under the U.S. Clean Water Act and EPA NPDES permitting framework.
COLFAX STP serves the city of Colfax, located in Whitman County, Washington. The plant treats wastewater from a population of about 2,845 people, making it a small-scale municipal facility in the inland Pacific Northwest. Under the U.S. Clean Water Act, plants of this size are typically required to meet secondary treatment standards through EPA National Pollutant Discharge Elimination System (NPDES) permits, administered by the Washington State Department of Ecology. These permits set effluent limits to protect water quality in receiving waters. The plant discharges treated effluent into the local watershed, which drains into the Palouse River, a tributary of the Snake River, and ultimately the Columbia River system. This river network supports diverse aquatic life and is important for regional agriculture and recreation.
Environmental context
The plant's treated effluent enters the Palouse River watershed, which flows into the Snake River and then the Columbia River before reaching the Pacific Ocean. This river system supports salmonid species and other aquatic life, making water quality management critical for downstream ecosystems and regional water resources.
Frequently asked questions
COLFAX STP is located at 425 West Walla Walla Highway in Colfax, Whitman County, Washington, United States.
COLFAX STP serves approximately 2,845 residents in the city of Colfax, Washington.
The plant discharges treated effluent into the local watershed, which drains into the Palouse River, a tributary of the Snake River and part of the Columbia River basin.
COLFAX STP operates under the U.S. Clean Water Act and is regulated through an EPA National Pollutant Discharge Elimination System (NPDES) permit, administered by the Washington State Department of Ecology.
For small municipal plants in the U.S., secondary treatment is typically required under the Clean Water Act, often involving biological processes such as activated sludge or lagoon systems, with NPDES permits setting specific effluent limits.
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