South Durango SD Wastewater Treatment Plant, La Plata County, Colorado

South Durango SD is a municipal wastewater treatment facility located in La Plata County, Colorado, serving a population of about 3,000 residents. The plant provides secondary treatment, a standard level for small communities in the United States, ensuring that pollutants are reduced before discharge. With a designed capacity of 1,703.43 cubic meters per day and an average daily flow of 378.54 cubic meters, the plant operates well below its capacity. Under the US Clean Water Act, such facilities are regulated through National Pollutant Discharge Elimination System (NPDES) permits, which set effluent limits to protect water quality. The treated wastewater is discharged into the local watershed, which ultimately drains into the Animas River, a tributary of the San Juan River. This river system supports diverse aquatic life and provides water for irrigation and recreation in southwestern Colorado. The plant's location inland and its secondary treatment level help mitigate environmental impacts on downstream ecosystems.

The plant discharges into the Animas River watershed, which flows into the San Juan River and eventually the Colorado River. This basin supports a variety of fish species and is an important water source for agriculture and communities in the arid Southwest. The secondary treatment process reduces organic matter and suspended solids, protecting aquatic habitats downstream.