Billings WWTP - Yellowstone County, Montana Wastewater Treatment Plant

Billings WWTP is a municipal wastewater treatment facility located on Cerise Road in Lockwood, Yellowstone County, Montana. The plant serves an estimated population of 91,750, placing it in the medium-to-large agglomeration category for US inland facilities. Its location near the Yellowstone River positions it within the Missouri River basin, ultimately draining to the Mississippi River system. As a US facility, Billings WWTP operates under the Clean Water Act's National Pollutant Discharge Elimination System (NPDES) permit program. For plants serving populations over 10,000, the EPA typically requires secondary treatment as a minimum standard. The plant's treatment processes and capacity details are not publicly available, but the regulatory framework ensures compliance with effluent limits designed to protect receiving waters. The plant's treated effluent discharges into the Yellowstone River, a major tributary of the Missouri River. This river system supports diverse aquatic life, including native fish species such as the pallid sturgeon and sauger. Downstream, the Missouri River flows into the Mississippi River and eventually the Gulf of Mexico, making nutrient management at this plant relevant to Gulf hypoxia concerns.

Billings WWTP discharges into the Yellowstone River, which flows into the Missouri River and then the Mississippi River before reaching the Gulf of Mexico. The Yellowstone River is one of the longest free-flowing rivers in the contiguous United States, supporting a diverse aquatic ecosystem including threatened species like the pallid sturgeon. Nutrient loading from wastewater treatment plants in this basin can contribute to downstream hypoxia in the Gulf of Mexico, making effluent quality important for regional water quality management.