LA CAPELLE II Wastewater Treatment Plant, La Capelle, Hauts-de-France

LA CAPELLE II is an advanced wastewater treatment plant located in La Capelle, a commune in the Aisne department of Hauts-de-France, France. The plant serves a population of approximately 5,058 people and has a designed capacity of 3,320 cubic meters per day, with a current discharge volume of 902.34 cubic meters per day. As an advanced treatment facility, LA CAPELLE II goes beyond secondary treatment to remove nutrients such as nitrogen and phosphorus, which is typical for plants in sensitive areas under the EU Urban Waste Water Treatment Directive (91/271/EEC). For agglomerations of this size (under 10,000 population equivalent), the directive requires appropriate treatment, and advanced treatment is often implemented to protect sensitive water bodies. The plant discharges treated effluent into the local watershed, which ultimately drains into the North Sea via the Oise River and the Seine River system. The Hauts-de-France region features a dense network of rivers and canals, and the plant plays a key role in maintaining water quality in this ecologically important basin.

The treated effluent from LA CAPELLE II enters the local watercourse, which flows into the Oise River, a major tributary of the Seine. The Seine River then discharges into the English Channel (La Manche) at the Seine Bay. This watershed supports diverse aquatic life and is an important migratory corridor for fish. The advanced treatment helps reduce nutrient loading, protecting downstream ecosystems from eutrophication.