One of the main pillars of the technical proposal for the improvement actions in the process of renewing the port concession was adaptation to climate change.

From a structural point of view, this adaptation has materialized with the increase in the height of the docks and piers to respond to the rise in average sea level, and with the reinforcement and resizing of the rock blocks of the outer protective breakwaters to better withstand the increased intensity and frequency of sea surges.

Regarding energy, the strategy has consisted of implementing photovoltaic installations for self-consumption, In a first phase, on all the roofs of the new buildings planned or rehabilitated; with this, in recent years, we have installed a peak power of 50 kW and achieved a self-sufficiency rate of 30% on an annual average. In the near future, it is planned to increase this power to no less than 250 kWp with new installations on pergolas, which will significantly increase our electrical independence, especially when we introduce storage elements, as well as allow us to meet new demands for electrified vehicles (including marine vehicles).

With the water vector, we need to act similarly. The water emergency situation we are experiencing has shown us our great vulnerability and our great dependence on this resource. In addition, the necessary social action on demand (let’s save water!) is not always compatible with the operation of certain sectors, such as tourism, which require this resource in their service provision process to customers intensively at certain times of the year. When this happens, we must also consider acting on the supply and be able to generate new water. In this sense, marinas are excellent facilities for proposing projects for the generation of fresh water by desalination of seawater through reverse osmosis processes.

Technical characteristics of the new reverse osmosis desalination plant

In our case, to do this, we opted for the acquisition of equipment from the company Eco-Sistems Watermakers. Specifically, we chose a T-2000 model, which is a reverse osmosis plant with the following technical characteristics:

• Production capacity: 2.1 m³/h (50 m³/day) of fresh water with an intake of 5.5 to 8 m³/h of seawater;
• Filtration system: primary filtration through a bed of sands of different granulometries and secondary micrometric filtrations using cartridge-type devices;
• Energy recovery: integrated energy recovery system in the piston pump that raises the pressure to 60 bars;
• Water treatment: pre-treatment with sodium bisulfite that acts as an anti-scaling and bactericidal agent, and post-treatment with sodium hypochlorite chlorination;
• Expected water condition at the outlet: for human consumption in compliance with the parameters of RD 140/2003 and its subsequent modifications;
• Remote and automated control: various sensors that allow configuration and monitoring of operational parameters, with remote control capability via the internet.

The T-2000 desalination plant is fully automatic, requires minimal human intervention, and is equipped with control systems to ensure its optimal operation. The components of the desalination plant are mounted on a self-supporting frame, which in our case is installed inside a 20-foot shipping container that had to be soundproofed to attenuate the sound power of the high-pressure piston pump.

The seawater intake is at a depth of 1.5 m under the dock called 100-200, while the reject will be evacuated under the dock 500-600.

The Club has proposed to the manufacturer the improvement of oversizing the seawater intake volume so that a part of this captured seawater goes directly to dilute the salt concentration of the reject, decreasing it by 30% compared to conventional machinery.

The process diagram can be seen in the following figure:

Regarding the controversy over the reject (brine production) of these reverse osmosis processes, in addition to what was mentioned earlier, it should also be noted that a significant part of the produced water is used for washing the boats and, therefore, returns to the sea with a negligible salt concentration that tends to compensate – at least globally – for the excess salt of that effluent. Additionally, it should be considered that a single daily astronomical tide (± 0.3 m) moves a renewal volume of interior waters of about 91,000 m³ (151,373 m² of interior water surface for 0.6 m of tidal range), which represents 13.4% of the total water contained in the port (678,680 m³); in other words, the totality of the port’s water is renewed, theoretically naturally, every week.

The system is completed with a 25 m³ capacity polyester reinforced with fiberglass (FRP) tank, a network of connecting pipes, and a pressure pump system with frequency inverters that must ensure sufficient flow and pressure throughout the installation.

A pilot project by the Club for a more sustainable future

The current system should be understood as a provisional installation and as a pilot test that can last between 2 and 3 years. If the device works correctly, in a subsequent phase of construction and coinciding with the urbanization of the parking area adjacent to the main building, it is planned to bury the machinery and design a larger tank, probably with a capacity greater than 50 m³, which is -currently- the maximum daily consumption on an August day.

The energy consumption of the desalination machinery is, according to tests, 3.3 kWh per m³ of desalinated water generated. The port’s water consumption is about 7,000 m³ on an annual average. Therefore, assuming that all the consumed water came from desalination, the associated energy consumption would be about 23,000 kWh/year, which is equivalent to one-third of the annual production of the current photovoltaic plants in self-consumption mode (in 2023, 64,500 kWh of energy were generated with our own renewable sources on the roof).

This new project, besides proposing a change of model in the management of the water consumed by the Club, also allows us to contribute sustainably to the preservation of local freshwater sources, benefiting the community and the local ecosystem.