Site assainissement Wastewater Treatment Plant, Saint-Pierre-de-la-Rivière-du-Sud, Québec

Site assainissement is a municipal wastewater treatment plant located at 350 Rue Principale in Saint-Pierre-de-la-Rivière-du-Sud, a small community in the Chaudière-Appalaches region of Québec, Canada. The plant serves a population of 617 and is classified as a small-scale facility under Canadian wastewater regulations. The plant provides secondary treatment, which is the minimum standard for municipal wastewater in Canada under the federal Wastewater Systems Effluent Regulations (WSER). Secondary treatment typically involves biological processes to reduce organic matter and suspended solids. The plant discharges an average of 277 m³ of treated wastewater per day. The treated effluent is discharged into a local watercourse that flows into the St. Lawrence River, one of the largest and most ecologically significant rivers in North America. The St. Lawrence River supports diverse aquatic life and is a critical migratory corridor for fish species. The plant's coastal location within 10 km of the St. Lawrence Estuary means its discharge contributes to the overall nutrient and pollutant load in this sensitive marine environment.

The plant discharges into a tributary of the St. Lawrence River, which flows into the St. Lawrence Estuary and ultimately the Gulf of St. Lawrence. The estuary is a biologically productive zone supporting fisheries, marine mammals, and migratory birds. As a coastal facility, the plant's secondary-treated effluent may contribute to nutrient enrichment in the estuary, which can affect algal blooms and oxygen levels in downstream waters.