Montdidier Wastewater Treatment Plant, Montdidier, Hauts-de-France

The Montdidier wastewater treatment plant is located in the commune of Montdidier, in the Somme department of the Hauts-de-France region, northern France. The facility serves a population of about 9,763 residents, classifying it as a small to medium agglomeration under EU classification. As a French wastewater treatment plant, Montdidier operates under the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for agglomerations with a population equivalent (PE) between 2,000 and 10,000 discharging into freshwater. The directive also mandates more stringent treatment if the receiving waters are designated as sensitive areas. The plant's treated effluent is discharged into local watercourses that ultimately drain into the Somme River basin. The Somme River flows into the English Channel, supporting diverse aquatic life and providing important ecological services in the region. The plant plays a key role in protecting downstream water quality and maintaining the health of the Somme estuary ecosystem.

The Montdidier plant discharges into the Somme River basin, which flows westward through the Hauts-de-France region before emptying into the English Channel via the Somme estuary. The estuary is an ecologically sensitive area that supports migratory bird populations and diverse fish species. The plant's treatment performance directly influences the water quality of the Somme River and its downstream environments.