LESTREM Wastewater Treatment Plant, Lestrem, Hauts-de-France

LESTREM is a municipal wastewater treatment plant located in Lestrem, a commune in the Pas-de-Calais department of Hauts-de-France, France. The plant serves a population of approximately 1,100 residents and is situated along the D 945 road. It operates under the French regulatory framework, which implements the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this scale. The plant provides secondary treatment, which is the standard required by the EU directive for inland freshwater discharges from agglomerations of this size. With a designed capacity of 4,500 m³/day and an average discharge volume of 196.24 m³/day, the facility operates well below its capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into local watercourses that ultimately drain into the Lys River, a tributary of the Scheldt. The Scheldt flows through Belgium and the Netherlands before reaching the North Sea. The plant plays a key role in protecting the Lys watershed from organic pollution and nutrient loading, supporting aquatic life and downstream water quality.

The plant discharges into the Lys River basin, which flows through the Hauts-de-France region and into Belgium. The Lys is a lowland river that supports diverse aquatic habitats and is used for agriculture and recreation. Downstream, the Scheldt estuary is an ecologically important area for migratory birds and fish. The plant's secondary treatment helps reduce organic pollutants and protect the river's ecological health.