Grass Range WWTF - Great Falls, Montana Wastewater Treatment Plant

Grass Range WWTF is a wastewater treatment facility located along Rivers Edge Trail in Great Falls, Cascade County, Montana. The plant serves a small population of 130 residents, reflecting its role in a rural or peri-urban setting within the state. The plant provides secondary treatment, which is the standard level required under the U.S. Clean Water Act for municipal wastewater facilities. Secondary treatment typically involves biological processes to remove organic matter and suspended solids. The plant's designed capacity is 143.85 units, with a current discharge volume of 102.21 units, indicating operational headroom. The treated effluent from Grass Range WWTF is discharged into the Missouri River watershed, which flows through central Montana and ultimately joins the Mississippi River system. The plant's operations are subject to National Pollutant Discharge Elimination System (NPDES) permits issued by the Montana Department of Environmental Quality, ensuring compliance with water quality standards to protect downstream aquatic life and recreational uses.

The plant discharges into the Missouri River basin, a major tributary of the Mississippi River. The Missouri River in this region supports diverse aquatic species, including native fish such as pallid sturgeon and sauger. The watershed is also important for irrigation and recreation. Downstream, the river flows through the Upper Missouri River Breaks National Monument, an ecologically sensitive area with unique riparian habitats.