Lagune Gibelin Wastewater Treatment Plant, Matoury, French Guiana

Lagune Gibelin is a municipal wastewater treatment plant located in Matoury, a suburb of Cayenne in French Guiana. The facility serves a population of about 4,381, classifying it as a small agglomeration under French regulations. It operates as a secondary treatment plant, which is the standard for communities of this size in the region. The plant has a designed capacity of 8,200 m³/day and currently treats an average daily flow of 781.56 m³, indicating significant spare capacity. As a French overseas department, the plant operates under French environmental law, which transposes the EU Urban Waste Water Treatment Directive (91/271/EEC). This directive requires secondary treatment for all discharges from agglomerations above 2,000 population equivalent, a standard Lagune Gibelin meets. The treated effluent is discharged into local waterways that drain into the Atlantic Ocean near the coast of French Guiana. The plant's proximity to the coast (within 10 km) means its discharge can influence coastal water quality and the sensitive mangrove ecosystems that fringe the Guiana coast. Proper treatment helps protect these habitats and the marine environment from nutrient pollution.

The plant discharges into small coastal streams that flow into the Atlantic Ocean near Cayenne. French Guiana's coastline features extensive mangrove forests and estuaries that serve as critical nursery habitats for fish and crustaceans. The region's tropical climate and high rainfall mean that surface water runoff and treated effluent can rapidly reach the ocean. Protecting these coastal waters from excessive nutrients and pathogens is essential for maintaining biodiversity and supporting local fisheries.