The demand for safe drinking water is outgrowing the planet’s natural resources at an alarming rate. The desalination industry has responded well and is constantly evolving by reducing the costs and improving the reliability of producing high quality water. However, despite remarkable progress, high costs and energy requirements are still critical factors preventing the wider adoption of desalination.
REvivED water focussed on the potential of electrodialysis for desalination applications, allowing the industry to benefit from the inherent advantages of this process, where only the ions (salt) flow through the membranes, rather than the water. This delivers benefits, both for the industry and for society as a whole: Decreased energy consumption and lowered carbon emissions, Flexibility to work with variable solar and wind energy input, Reducing the amount of chemicals used to keep the membranes clean.
Overall, based on the project results it can be concluded that:
• While ED is not commercially competitive for water softening applications, it is a very suitable technology for brackish water desalination. It is feasible and cost-competitive and can be used in any brackish water application, including for decentralised water provisions in remote areas without any available infrastructure.
• It is possible to use multi-stage ED systems for seawater desalination. The technology has been scaled-up to industrial size and it has been successfully demonstrated that lower energy consumption than state-of the art technologies can be achieved.
• ED can work in tandem with RO for seawater desalination. Different configurations are possible for combining the two technologies and the benefits depend on local conditions, but it has been demonstrated that in principle the two technologies can work well together.
• If a low salinity water source is available (such as treated wastewater), it can be used through (assisted) reverse electrodialysis ((A)RED) for pre-desalinating seawater, bringing the energy requirements of seawater desalination to very low levels. Regulatory issues associated with wastewater reuse would have to be clarified before this option could be used in practice.