The processes to purify and regenerate water always generate some type of waste. Everything that should not remain in it for it to be suitable for oral consumption, remains in the treatment plant. And practically, all of these products can have a utility through which they go from waste to raw materials: agricultural or industrial uses, energy, fuels, etc. It is the application of the circular economy, which is also part of daily life in water regeneration plants.
In desalination plants, the majority of the waste resulting from the desalination process is brine, seawater with double the concentration of salt. Which is returned to the sea through diffusers that prevent it from generating a negative local environmental impact.
Minerals, metals…
Now, brine contains mineral resources and metals, such as lithium or manganese, essential for various technological industries. Returning it to the sea without taking advantage of these possibilities is “not extracting the true value of that current,” as Víctor Monsalvo, head of the Eco-efficiency Area in the Innovation and Technology department of Aqualia, says.
Therefore, returning brine to the sea is no longer an option. On the contrary. Aqualia’s Innovation and Technology department has made progress in recent years in various lines of work in its testing laboratory in Tenerife, where innovative technologies in seawater desalination processes are developed and validated. And from there the Sea4Value project has come.
And gourmet salt!
In addition to the minerals, the salt concentrated in the brine has also attracted the attention of Aqualia’s Innovation area. So much so as to find a use for another product of the seawater desalination process and that instead of industries or agriculture it is directed to kitchens. Alma de mar, a line of gourmet salts, is the result of combining traditional and innovative processes that have managed to obtain a highly pure and enriched salt to which eight different flavors have been added to give it a touch that makes it special.
“One of the advantages of producing salts from the desalination plant is that we obtain a highly pure salt, thanks to the fact that the process itself eliminates impurities present in the sea,” explains Monsalvo.
To this end, Aqualia has developed a sustainable process that exclusively uses energy from the sun and wind, and that combines the traditional system of brine extraction from seawater with new technologies. «The process, Monsalvo details, is more efficient and requires less space. Thanks to the desalination plant we start with a concentration of salts higher than that of seawater. And we adapt the method to maximize salt recovery and guarantee its purity depending on the climatic conditions: sun and wind, fundamentally. From there, the different destinations of the resulting salt emerge: industrial or food, as in this case.
Regulations for culinary use
Alma de mar complies with technical-sanitary regulations such as virgin sea salt and fleur de sel. The brand, which has been registered in 38 countries, is an example of the extent to which resources resulting from water cycle processes can be reused.
In line with the European Raw Materials Law, which aims to guarantee a safe and sustainable supply of fundamental raw materials for European industry and reduce dependence on imports, the recovery of these compounds present in the concentrate of desalination plants represents new technological and economic opportunities linked to desalination.