Downsville STP - Secondary Wastewater Treatment Plant in Downsville, Louisiana

Downsville STP is a municipal wastewater treatment facility located in Downsville, Lincoln Parish, Louisiana. It serves a small population of 647 residents, reflecting the rural character of the area. The plant operates under the regulatory framework of the US Clean Water Act, which requires secondary treatment for municipal discharges to protect water quality. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. Its designed capacity is 264.98 units, with an actual discharge volume of 109.78 units, indicating operational headroom. As a small facility in an inland setting, it is subject to state-level NPDES permits that set effluent limits based on the receiving water body's assimilative capacity. The treated effluent is discharged into local waterways that drain into the Ouachita River basin, ultimately reaching the Mississippi River and the Gulf of Mexico. The plant's operations help protect downstream aquatic ecosystems, including fish and wildlife habitats in the region's bayous and rivers.

The plant discharges into local streams that are part of the Ouachita River watershed, which flows into the Mississippi River and then the Gulf of Mexico. This inland location supports a diverse range of aquatic life, including fish species such as bass and catfish, and provides habitat for migratory waterfowl. The secondary treatment process reduces nutrient loads, helping to prevent eutrophication in downstream water bodies.