Desalination of sea water is already used in the supply of drinking water by some hotel companies in the Algarve, in some cases to reduce public consumption and save resources, in others because it is the only possible solution.
Situated on a cliff framed by the Algarve coast, the Vila Vita Parc development, in Porches, Lagoa, started in the desalination of sea water in 2015 and, although the project was designed to irrigate the property's green spaces, it quickly expanded to other sources of water consumption.
“Initially we started to work only for the irrigation system and found that the capture, in view of the need and the dimension of our system, allowed us to reach the lakes and at this moment we are already supplying about seven pools, only with this water capture. ”, André Matos, Vila Vita Parc quality director, explained to Lusa.
With a dimension of 23 hectares, more than half of which are green spaces, the administration of the luxury tourist resort has launched the construction of an underground desalination station, which operates under a tennis court, without the guests realizing it. existence.
“At this moment, of the 100% that we were going to look for in the chain in 2014, we are going to look for only about 30% for the functioning of everything else: accommodation, bath and drinking water for restaurants”, quantifies André Matos, showing himself satisfied with the savings levels achieved.
Convinced that, in the future, water will be a consumer good with “a high economic value”, that responsible considered that, as “responsible polluters”, they must guarantee that, like the future of the next generations, “the future of the business be supported by solid pillars ”and that respect the environment.
Per hour, the desalination system installed in Vila Vita Parc allows to capture 24 cubic meters of seawater – which represents 24,000 liters.
Per day, it has the capacity to capture 440 cubic meters (440,000 liters), which "at the end of the year may represent around 900 pools of 650 cubic meters".
With a much smaller dimension, but with an older use, businessman José Vargas also installed, 12 years ago, a mini seawater desalination station under his restaurant built on piles on the Deserta island, in Faro, which as the name indicates, it doesn't have any houses.
Also in this case, reverse osmosis technology is used, a process of purifying water through membranes, in which salt water is forced to pass through the membrane, which removes the particles of salts, transforming sea water into water ' pure '.
“We had to resort to this solution because there was no other solution. Since there is no water in the network and there are also no drinking water wells, we had to resort to desalination, ”said the businessman, who has operated a restaurant there for over 30 years.
Per hour, the system has the capacity to capture 80 liters of sea water and, although the system is not always working, “in the limit it would be two thousand liters in 24 hours.
According to José Vargas – who used a 'desalination kit' used in yachts and adapted it to the restaurant's installation – to 'manufacture' one liter of drinking water requires five liters of sea water.
“We only consume this water (desalinated) for gastronomic consumption: ice, kitchens, washing dishes. Then we use another water that we draw from a well here, which we treat with chlorine, for the black waters of the bathrooms, ”he explained.
The desalination of sea water is also one of the proposals contained in a plan that is being designed for Culatra, another of the barrier islands of Ria Formosa, 'neighbor' to Deserta, but which, unlike this one, is a kind of village: it has a school, a social center, a health center and even a church.
“It is a key project for the island, in terms of drinking water resources. However, it is perhaps the most expensive solution. It is the project that will collect the largest investment, ”André Pacheco, coordinator of the Culatra 2030 – Sustainable Energy Community project, told Lusa.
Since 2009, Culatra, in the municipality of Faro, has started to be supplied by the public network, but “there is a huge expenditure of energy to pump drinking water” to the island, as well as to pump waste water to treatment plants, he noted that responsible.
One of the main concerns of the desalination project that is being conceived for the island is the destination of the waste produced, a process that, according to the oceanographer at the University of Algarve, still requires a lot of research.
“What is our objective in the Culatra 2030 project is to study how this residue, that is, a hypersaline solution contaminated with sulfites, can be used in the circular economy as a raw material for another industrial process”, he underlined.
However, for André Pacheco, the problem of lack of water is not solved, by itself, with desalination, but, above all, with “a different way” of looking at water.
"We use drinking water for a lot of uses that we don't need: we wash cars with drinking water, we wash dishes with drinking water," he exemplified.