Spain’s Acciona, a leader in the provision of regenerative solutions for a decarbonised economy, has successfully tested a next-generation reverse osmosis (RO) configuration designed to improve the energy efficiency and sustainability of seawater desalination, as part of the European innovation project Life Indesal.
The pilot system, operated for nearly two years at the Leading Experimental Accelerator in Desalination (LEAD) facility at the San Pedro del Pinatar plant in Spain, demonstrated stable performance while producing high-quality permeate water with total dissolved solids below 200 mg/L.
According to Acciona, results from the project show that the new configuration can reduce the energy consumption of reverse osmosis processes compared with conventional systems.
Acciona explains that the improvement is achieved mainly through the implementation of low-pressure multistage reverse osmosis, in which shorter pressure vessels enable a better flux distribution. Moreover, thanks to this configuration, more tailored membrane-cleaning strategies can be applied to tackle fouling issues. These can help optimise plant performance while maintaining high water quality.
Beyond energy savings, the project also explored new ways to enhance circularity in desalination plants by making use of brine streams generated during the process. During the demonstration phase, the system was able to generate renewable energy from brine (0.1 kWh per cu m of brine) by reverse electrodialysis and produce chemical reagents on site derived from the same stream applying electrodialysis with bipolar membranes.
This approach could allow desalination facilities in the future to generate the cleaning chemicals required for membrane maintenance directly within the plant, potentially increasing operational self-sufficiency while reducing the need for external chemical supply, says Acciona.
While the solution is currently at pilot stage, the configuration developed within Life Indesal could potentially be scaled for use in future seawater desalination plants or integrated into existing facilities through partial retrofits, says Acciona.
“With water scarcity becoming an increasingly pressing global challenge, improving the efficiency and sustainability of desalination technologies is a key priority in many water-stressed regions around the world,” says a spokesperson for Acciona.
The €3.1 million ($3.66 million) Life Indesal project, coordinated by Acciona, involves partners including the University of Cantabria’s Department of Chemical and Biomolecular Engineering, APRIA Systems, REDstack and Revolve. The findings could pave the way for scaling the technology in future seawater desalination projects or retrofitting existing facilities. The initiative highlights how innovation and international collaboration can help develop more energy-efficient and circular solutions for the future of desalination.