CALA LLONGA Wastewater Treatment Plant, Santa Eulària des Riu, Ibiza

CALA LLONGA is an advanced wastewater treatment plant located in the coastal urbanisation of Cala Llonga, within the municipality of Santa Eulària des Riu on the island of Ibiza, Illes Balears, Spain. The plant serves a population of 1,545 and has a design capacity of 7,000 m³ per day, with an average discharge volume of 549.09 m³ per day. As an advanced treatment facility, it goes beyond secondary treatment to remove nutrients and other pollutants, meeting stringent standards under the EU Urban Waste Water Treatment Directive (91/271/EEC). This directive requires advanced treatment for discharges into sensitive areas, which is relevant given the plant's coastal location and the ecological sensitivity of the Mediterranean Sea. The treated effluent is discharged into the coastal waters of the Mediterranean Sea near Cala Llonga. The surrounding marine environment supports diverse aquatic life and is an important area for tourism and recreation. The plant plays a key role in protecting local beaches and coastal ecosystems from pollution.

The plant discharges treated wastewater into the Mediterranean Sea near Cala Llonga, a coastal area on the eastern side of Ibiza. The Mediterranean is a semi-enclosed sea with limited water exchange, making it sensitive to nutrient pollution. The advanced treatment helps protect local marine habitats, including seagrass meadows and fish spawning grounds, which are vital for biodiversity and the island's tourism economy.