ECQUES SE Wastewater Treatment Plant, Ecques, Hauts-de-France

ECQUES SE is an advanced wastewater treatment plant located in Ecques, a commune in the Pas-de-Calais department of Hauts-de-France, France. The plant serves a population of 2,633 and has a designed capacity of 1,800 m³/day, with a current discharge volume of 469.72 m³/day. As a small agglomeration, it operates under the EU Urban Waste Water Treatment Directive 91/271/EEC, which requires appropriate treatment for discharges into freshwater and estuarine areas. The plant employs advanced treatment processes, which go beyond secondary treatment to remove nutrients and other pollutants. This level of treatment is typical for sensitive areas or where receiving waters require higher protection. The plant's capacity utilization suggests it operates well below its design capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into local watercourses that eventually flow into the North Sea via the Aa River basin. The region's aquatic ecosystems benefit from the advanced treatment, which helps maintain water quality in downstream rivers and coastal zones. The plant's inland location reduces direct marine impact, but its proximity to the coast (within 50 km) means its discharges can influence coastal water quality through river transport.

The plant discharges into the Aa River basin, which flows through the Hauts-de-France region before reaching the North Sea near Gravelines. The downstream environment includes lowland rivers and coastal wetlands that support diverse aquatic life, including fish species such as Atlantic salmon and European eel. Advanced treatment at this plant helps reduce nutrient loading, which is critical for preventing eutrophication in the sensitive coastal waters of the southern North Sea.