MARKSVILLE LAGOON WWTP - Marksville, Louisiana Wastewater Treatment Plant

MARKSVILLE LAGOON WWTP is a municipal wastewater treatment facility located in Marksville, Avoyelles Parish, Louisiana. The plant serves a population of approximately 4,998 residents, making it a small to medium-sized agglomeration typical of rural Louisiana communities. As a lagoon-based system, the plant provides treatment through natural biological processes in aerated or facultative ponds. Lagoon systems in the United States are regulated under the National Pollutant Discharge Elimination System (NPDES) permit program, which sets effluent limits based on the receiving water body's assimilative capacity. The plant discharges treated wastewater into local waterways that ultimately drain into the Mississippi River Basin. The facility plays a key role in protecting downstream water quality in the Atchafalaya Basin, a ecologically significant floodplain and swamp ecosystem that supports diverse aquatic life and migratory birds.

The plant's treated effluent flows into tributaries of the Red River, which joins the Mississippi River and eventually reaches the Gulf of Mexico. The Atchafalaya Basin downstream is a large river swamp that provides critical habitat for fish, waterfowl, and other wildlife. Protecting this watershed from nutrient pollution is important for maintaining water quality in the Gulf's hypoxic zone.