Venturi diffusers as enhancing devices for the dilution process in desalination plant brine discharges

摘要

Brine discharges from desalination plants spread out over broad spatial scales, affecting the benthic communities encountered along the way. Because of this, it is essential to develop technology enhancement initiatives for brine discharge processes that are economically feasible and effective for both planned and existing desalination plants. The technical feasibility of using venturi diffusers rather than conventional devices to enhance dilution processes was studied at the Maspalomas Ⅱ desalination plant, in the south of the island of Gran Canaria (Canary Islands-Spain). The venturi eductors needed very high exit velocities (≥11m/s) to reach the pressure difference required to produce the suction effect of these devices. At these velocities, the venturi eductors were more efficient than conventional diffusers, as they achieved much higher dilutions of around 39 as opposed to 27. Dilutions as high as these are not only very useful, but also necessary, as part of the island's largest and most ecologically important seagrass meadow of Cymodocea nodosa is found nearby.