Dispersion of desalination plant brine discharge under varied hydrodynamic conditions in the south of Gran Canaria

Abstract

Brine discharged directly into the sea from desalination processes, forms a very dense plume that spreads out over the sea floor following the steepest slope due to its greater density than ambient sea water. Because the large difference in density slows down brine dilution processes in ambient sea water, hypersaline plumes spread out over broad areas and affect the benthic communities in their path. The Maspalomas II desalination plant, in the south of the island of Gran Canaria (Canary Islands-Spain), discharges brine through an underwater outfall over a wide sandy bottom with a mild slope. The behavior of this brine discharge was characterized under various hydrodynamic conditions. A higher degree of hydrodynamic exposure favored dilution of the outer edges of the plume, helping to reduce the area of influence.

Keywords:

• Desalination
• Brine
• Discharge
• Outfall
• Plume
• Hydrodynamic conditions
• Dilution
• Dispersion

Acknowledgments

This study was conducted as part of the project “Technical feasibility study of venturi diffusers in desalination plant brine discharges to enhance the dilution process and reduce the environmental impact on marine ecosystems”, under the Spanish National Programme for Experimental Development Projects, within the Ministry of the Environment and Rural and Marine Affairs, Environment and Eco-Innovation Sector, Management and Sustainable Uses of Natural Resources Subsection. The authors are grateful to A. Arencibia and F. Roch, from General Electrics, for their support, M. Antequera and A. Ruiz, from CEDEX, and J. McGrath, for translation of the manuscript from Spanish.