Resource recovery from desalination, the case of small islands

Unidad de excelencia María de Maeztu CEX2019-000940-MThis work explores resource recovery coupled to seawater desalination in small islands. As small islands depend on seawater desalination for water access, they make an excellent ground for exploring the trade-offs associated to resource recovery, like potential economic gains, energy use, and environmental impacts. Here, we investigated these tensions in the context of Lampedusa, in Italy. We then developed and evaluated scenarios for the recovery of additional water, Mg, and other resources from brines, to identify if and how resource recovery is an interesting approach for the island vis-à-vis these tensions. We have found that the potential to increase water production with water recovery from brine is an interesting alternative for small islands, especially when harnessing waste heat. However, while some technologies offer possibilities for recovering additional resources, in places like small islands the potential benefits from additional recovery do not seem to justify the costs to the local system

Valorization of seawater desalination brines through the integration of Eutectic Freeze Crystallization and Electrodialysis with Bipolar Membranes innovative technologies

European policy encourages the adoption of sustainable systems that promote the efficient use and recovery of resources. Accordingly, this study proposes integrating two innovative technologies, including Eutectic Freeze Crystallization (EFC) and Electrodialysis with Bipolar Membranes (EDBM), for treating seawater desalination brines. Two experimental campaigns were conducted to assess the viability of this novel treatment chain. Using two lab-test rig units, the effect of various operating conditions on the outputs and general performance of both EFC and EDBM was evaluated. Firstly, results showed that EFC could manage seawater brines to (i) obtain pure sodium sulphate, and fresh water in the form of ice and (ii) provide a NaCl concentrate stream to EDBM. Secondly, regardless of the feed salt concentration, EDBM can operate with high current densities without significantly affecting the current efficiency, thus resulting in high conversion rates. Within the circular economy concept, the present study demonstrates that this integrated system is effective for minimizing seawater desalination waste streams