BIACHE SAINT VAAST Wastewater Treatment Plant, Biache-Saint-Vaast, Hauts-de-France

The BIACHE SAINT VAAST wastewater treatment plant is located in Biache-Saint-Vaast, a commune in the Pas-de-Calais department of Hauts-de-France, France. The plant serves a population of approximately 3,600 residents and has a designed capacity of 5,400 cubic meters per day, with an average discharge volume of 642.23 m³/day. As an advanced treatment facility, the plant goes beyond secondary treatment to remove nutrients and other pollutants, meeting stringent standards under the EU Urban Waste Water Treatment Directive (91/271/EEC). For small agglomerations like Biache-Saint-Vaast (under 10,000 population equivalent), the directive requires appropriate treatment, and the advanced level here indicates a high degree of environmental protection. The treated effluent is discharged into the local water system, which ultimately drains into the Scheldt River basin. The plant plays a key role in protecting the region's water quality, supporting both local aquatic life and downstream ecosystems in the Scheldt estuary and the North Sea.

The plant discharges into the Scheldt River basin, which flows through northern France and Belgium before reaching the North Sea via the Western Scheldt estuary. This watershed supports diverse aquatic habitats and is an important migratory corridor for fish. The advanced treatment helps reduce nutrient loading, protecting the estuary's sensitive ecology from eutrophication.