St Stephen Lagoon Wastewater Treatment Plant, St. Stephen, New Brunswick

St Stephen Lagoon is a municipal wastewater treatment facility serving the Municipal District of St. Stephen in Charlotte County, New Brunswick, Canada. The plant is located along Waterfront Trail in the community of Crocker Hill, near the border with the United States. It serves a population of approximately 6,539 residents, classifying it as a small to medium agglomeration under Canadian wastewater management frameworks. The plant operates as a lagoon system, a common treatment method in rural and semi-urban areas of Canada. Lagoons typically provide secondary-level treatment through natural biological processes, including stabilization ponds and facultative lagoons. Lagoon systems are designed to meet provincial effluent standards under New Brunswick's Clean Water Act and the federal Canadian Environmental Protection Act. The treated effluent from St Stephen Lagoon is discharged into the St. Croix River watershed, which flows southward into Passamaquoddy Bay and the Bay of Fundy. The St. Croix River is a transboundary waterway shared with the United States, supporting diverse aquatic life and serving as an important habitat for fish species such as Atlantic salmon and brook trout. The plant's location inland reduces direct marine impact, but its discharge contributes to the overall water quality of the St. Croix River system.

St Stephen Lagoon discharges into the St. Croix River watershed, which flows into Passamaquoddy Bay and ultimately the Bay of Fundy. The St. Croix River is a transboundary waterbody supporting diverse aquatic ecosystems, including Atlantic salmon and migratory fish. The plant's inland location reduces direct marine discharge, but its effluent quality affects downstream estuarine and coastal habitats. The Bay of Fundy is known for its high tidal range and productive marine environment, making nutrient and pollutant management critical for maintaining ecological balance.