Fluidra supplies technology to the Marbella desalination plant, one of the largest in Spain

Fluidra, a multinational group dedicated to developing applications for the sustainable
use of water, has been working through its subsidiary, Astramatic, on the
remineralisation of the Marbella desalination plant since the beginning of the year.
The plant supplies fresh water to the Costa del Sol region.
The Marbella desalination plant was commissioned in 2005 and is one of the largest
in Spain. Our country has more than 700 desalination plants for both saltwater and
seawater. The Marbella plant has eight production lines and a capacity for producing
56,000 m³ per day (2400 m³/hour), which means an annual supply of around 20 cubic
hectometres. The plant is owned by the Association of Municipalities of the Western
Region of the Costa del Sol.
The water supplied by the Marbella desalination plant and the future water
management projects in the area guarantee the supply to the Costa Del Sol region in
all weather conditions, as well as the sustainable development of the tourist sector,
which is of key importance for the Andalusian economy.
Technological progress
The desalination technology used by the Marbella plant comprises inverse osmosis
membranes. The desalinated water obtained by membranes has a low pH value
(approximately 5.5) and is low in calcium and alkalinity owing to the high-level
rejection of these ions by the membranes. As a result, the water produced is not
balanced. Until now, to obtain water that is apt for human consumption, the
osmotised water was mixed with a certain percentage of fresh water from the saltwater reservoir, which is not a good option during periods of drought. Astramatic
has proposed remineralisation as an alternative technique for producing fresh water.
Thanks to remineralisation, the water obtained is balanced and meets the technical
and health regulations for the supply and quality control of freshwater for public
consumption. The installation comprises a lime storage silo with a capacity for 82 m³,
an endless lime dispenser, a lime water formation tank, pumping units for pumping
the lime water to the saturator, pumping unit for pumping the osmotised water to the
saturator, a saturator (decanter), a saturated water pumping unit and a bypass with a
DN600 static mixer with a DN400 bypass.
The remineralisation process also includes a post-chlorination system that enables
the re-chlorination of the water to meet health standards on the presence of residual
chlorine. This is necessary because, during the seawater desalination process, any
possible levels of chlorine are reduced to zero through the addition of sodium
bisulphite to prevent its oxidising properties from damaging the system membranes.
Astramatic supplies this post-chlorination process: storage tanks, dispensation
pumps with adjustable flow volume for the materials required to withstand the liquid
that is pumped and designed to work in continuous or discontinuous mode; a safety
valve; a PVC pipe for injecting bleaching soda; and the option for selecting the flow
volume that is to be dispensed from the control panel.