SWRO Brine Characterisation and Critical Analysis of Its Industrial Valorisation: A Case Study in the Canary Islands (Spain)

The most recent years of research have shifted the perception of desalination brine from being waste to a high-value resource, in consonance with a circular economy perspective. The Canary Islands, containing the largest number of desalination plants per square kilometre in the world, are a perfect location to study its characteristics and evaluate its potential. A total of 10 heterogeneous seawater reverse osmosis plants were selected to determine the brine's physicochemical characterisation, comprising 37 parameters, and its correlation to the technical and operational aspects of the desalination plants. The results show a stable narrow range of the percentage of major ions concentration in relation to the total dissolved solids (55% Cl-, 29.5% Na+, 8% SO42-, 4% Mg2+, 1.5% Ca2+, 1.2% K+, 0.5% HCO3-, and 0.2% Br-) irrespective of specific differences between plants. The results obtained in this study are highly beneficial to industrial suppliers and future users of desalination brine valorisation (DBV) technologies, allowing an estimation of the chemical composition of a brine through knowledge only of its conductivity. Such information is crucial before investing in and optimizing DBV technologies. Nonetheless, from an environmental, economic, operational, energy-based, and R&D point of view, several improvements are required to promote their large-scale feasibility and viability.

Automated summary

Recent research has shown that desalination brine can be seen as a valuable resource rather than waste, and the Canary Islands are an ideal location to study its characteristics and potential. The results of this study are beneficial for industrial suppliers and future users of desalination brine valorisation (DBV) technologies, as they can estimate the chemical composition of brine based on its conductivity. However, further improvements and research are needed to enhance its large-scale feasibility and viability.