Crosby POTW - Secondary Wastewater Treatment Plant in Stephenson, Mississippi

Crosby POTW is a publicly owned treatment works located in Stephenson, Mississippi, within Amite County. The plant serves a small population of 555 residents and operates as part of the municipal wastewater infrastructure for the Crosby area. The plant provides secondary treatment, which is the standard level required under the U.S. Clean Water Act for municipal wastewater facilities. With a designed capacity of 227.12 cubic meters per day and an average daily discharge of 189.27 cubic meters per day, the plant operates below its design capacity. Facilities of this scale in the United States are typically regulated under the National Pollutant Discharge Elimination System (NPDES) permit program, administered by the Mississippi Department of Environmental Quality. The treated effluent from Crosby POTW is discharged into local waterways that drain into the Homochitto River, a tributary of the Mississippi River. The Mississippi River ultimately flows into the Gulf of Mexico, supporting diverse aquatic ecosystems and providing critical habitat for fish and migratory birds. The plant's location inland, more than 50 kilometers from the coast, reduces direct marine impact.

Crosby POTW discharges into streams within the Homochitto River basin, which flows into the Mississippi River and then the Gulf of Mexico. The watershed supports diverse aquatic life, including fish species such as bass and catfish, and provides important habitat for migratory waterfowl. The plant's inland location reduces direct coastal nutrient loading, but its discharge contributes to the overall nutrient and pollutant load in the Mississippi River system, which has implications for the Gulf of Mexico hypoxic zone.