STEU du GRAND PRADO Wastewater Treatment Plant, Sainte-Marie, La Réunion

STEU du GRAND PRADO is a major wastewater treatment facility located in Sainte-Marie, on the island of La Réunion, an overseas department of France. The plant serves a population equivalent of 166,509, classifying it as a large agglomeration under EU regulations. Its coastal location on the Indian Ocean island places it in a sensitive environmental context. As a French overseas territory, the plant operates under the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires advanced treatment for agglomerations over 150,000 population equivalent discharging into sensitive areas. Given the island's coastal and marine environment, the plant likely provides tertiary treatment to protect coral reefs and marine biodiversity. The directive mandates strict nutrient removal to prevent eutrophication in such sensitive waters. The treated effluent is discharged into the Indian Ocean, likely via a marine outfall. La Réunion's coastal waters support diverse marine life, including coral reefs and sea turtle habitats. The plant plays a critical role in safeguarding these ecosystems from nutrient pollution and pathogens, contributing to the island's environmental health and tourism appeal.

The plant discharges into the Indian Ocean near Sainte-Marie, on the northeastern coast of La Réunion. The island's coastal waters are part of a fragile marine ecosystem that includes coral reefs, seagrass beds, and habitats for endangered species like green sea turtles. Nutrient loading from wastewater can cause algal blooms and coral degradation, making advanced treatment essential. The plant's operations are governed by the EU Urban Waste Water Treatment Directive, which designates coastal waters as sensitive areas requiring nutrient removal.