Multi-million-euro contract awarded to complete modernisation of western Costa del Sol desalination plant

Acosol, the water supply company on the western Costa del Sol, has just awarded Sacyr Agua the third mega-contract for the optimisation of the Marbella desalination plan, which serves as something of a lifeline for the 11 municipalities on the strip of coast to the west of Malaga city. The awarded company will be responsible for the energy modernisation contract, worth 7.6 million euros, with a completion period of 22 months. It is a strategic action in environmental and economic terms, given the demands of a plant of these characteristics and the reverse osmosis processes.

The work tender had attracted the interest of several giants in the sector: Aquambiente-Elmasa, Cox Water, Drace Geocisa-Covico, Medio Ambiente Residuos Agua y Marea (the contractor for the two phases of expansion from six to 20 million cubic metres), Remondis Agua, Tedagua; Naxfor and Sacyr Agua.

On 31 May, the Marbella desalination plant completed the second phase of its expansion or, more precisely, the recovery of its initial design capacity. It can now produce 20 million cubic metres per year for a population that needs around 90, so the buffer added to the La Concepción reservoir, wells and other resources of the municipalities is valuable.

Acosol had already awarded the management of the energy work to the alliance of consultants Narval and Prydo for 229,989 euros. The renovation work aims to save up to 30% of energy.

"To achieve the savings, energy improvements will be made to the seawater collection pumping system, intermediate pumping in the pre-treatment, product water pumping and the high-pressure pumping system through isobaric chamber type energy recuperators. All this will contribute to reducing the total electricity consumption to produce desalinated water," say the specifications, published in the journal of the EU.

The total cost for the project to save energy is ten million euros, of which three million will be provided by the Andalusian energy agency, with the possibility of a European fund support. The rest will come from the Mancomunidad association of the Costa del Sol municipalities.

The contractor will have to draw up the project and subsequently execute the work. It is essential to improve energy efficiency in a plant that works with powerful pumps and high pressure systems and in which the cost is one of the main maintenance variables. Moreover, the desalination plant's peak electricity requirements have sometimes caused outages in the surrounding area.

The specifications highlight the need to programme the work in such a way as to condition the day-to-day operation of the desalination plant as little as possible. The final project will have to be supervised by the central government, which owns the plant. Moreover, energy efficiency was one of the bases of the agreement signed by the Mancomunidad and state-owned water company Acuamed in 2006.