Mandeville STP - Wastewater Treatment Plant in Mandeville, Louisiana

Mandeville STP is a municipal wastewater treatment facility located in Mandeville, St. Tammany Parish, Louisiana. The plant serves a population of about 12,018, placing it in the small-to-medium agglomeration category under U.S. regulatory frameworks. As a U.S. facility, Mandeville STP operates under the Clean Water Act's National Pollutant Discharge Elimination System (NPDES), which requires permits for discharges into surface waters. The plant has a designed capacity of 1.00 million gallons per day, indicating it is sized to handle the community's wastewater flows. The plant's treated effluent is discharged into the Lake Pontchartrain watershed, which drains into the Gulf of Mexico via the Rigolets and Chef Menteur Pass. Lake Pontchartrain is a large estuarine system that supports diverse aquatic life, including fish, crabs, and migratory birds. The plant's discharge contributes to the nutrient and water quality dynamics of this ecologically sensitive basin.

Mandeville STP discharges into the Lake Pontchartrain basin, which connects to the Gulf of Mexico through the Rigolets and Chef Menteur Pass. Lake Pontchartrain is a brackish estuary that supports a rich ecosystem, including seagrass beds, oyster reefs, and critical habitat for migratory waterfowl. Nutrient loading from wastewater discharges can affect water quality and algal blooms in this shallow lake, making treatment performance important for downstream ecological health.