ISTRES ENTRESSEN GCHENE Wastewater Treatment Plant, Istres, France

ISTRES ENTRESSEN GCHENE is a municipal wastewater treatment plant located in the Entressen district of Istres, in the Bouches-du-Rhône department of southern France. The plant serves a population of 4,425, classifying it as a small agglomeration under the EU Urban Waste Water Treatment Directive (91/271/EEC). The plant provides secondary treatment, which is the minimum standard required by the EU directive for freshwater discharges from agglomerations of this size. With a designed capacity of 5,000 m³/day and a current discharge volume of 789.41 m³/day, the facility operates well below its capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into the local watershed, which ultimately drains into the Mediterranean Sea via the Étang de Berre lagoon. This coastal lagoon is an ecologically sensitive area that supports diverse aquatic life and migratory birds. The plant's location within 50 km of the coast underscores its role in protecting downstream marine environments from nutrient pollution.

The plant discharges into the local watershed that flows into the Étang de Berre, a large coastal lagoon connected to the Mediterranean Sea. This lagoon is an important ecological site, supporting diverse fish populations and serving as a stopover for migratory birds. The secondary treatment provided helps reduce organic load and suspended solids, mitigating eutrophication risks in the sensitive lagoon ecosystem.