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Low energy solution for drinking water production by a REvival of ElectroDialysis systems

Periodic Reporting for period 2 - REvivED water (Low energy solution for drinking water production by a REvival of ElectroDialysis systems)

Reporting period: 2017-11-01 to 2019-04-30

The demand for safe drinking water is outgrowing the planet’s natural resources at an alarming rate. Climate change, drought, urbanisation, and pollution are just a small number of factors that are accelerating the crisis. Around 2 billion people live in areas of water scarcity and another 1.6 billion people face water shortage because their countries lack the necessary infrastructure to take water from rivers and aquifers to the populations that need it. If the efforts to combat climate change are not intensified, by 2025 two-thirds of the world population could be under water stress conditions.

The desalination industry has responded well to the increasing demand and is constantly evolving by reducing the costs and improving the reliability of producing high quality water. Despite remarkable progress so far, the high costs and energy requirements are still critical factors preventing the wider adoption of desalination. Continuous innovation is necessary to make the desalination technology more affordable.

REvivED water is focusing on the potential of electrodialysis for desalination applications, both as stand-alone systems and in combination with established desalination technologies. The project builds on the advanced ion exchange membranes with performance and cost that make electrodialysis suitable for desalination applications. This allows the industry to benefit from the inherent advantage of electrodialysis, where only the ions (salt) flow through the membranes, rather than the water. This delivers huge benefits:
• Decreased energy consumption – lowering carbon dioxide emissions and reducing money spent on energy.
• Flexibility to work with variable energy input – making it suitable for combination with solar and wind energy.
• The membranes stay cleaner for longer - reducing the amount of chemicals and energy used to keep the membranes clean and efficient.
In the first 3 years of the REvivED water project’s lifetime, the consortium has made progress with the development of brackish-water and seawater desalination systems.

Currently the project partners have installed three brackish water desalination systems in remote locations of Africa (in Somaliland, Tanzania and Djibouti). They provide clean drinking water to the local populations and are powered only by solar energy.

A pilot plant that combines Electrodialysis (ED) with reverse osmosis has been installed in Spain. The plant has a capacity of 25 m3/day and demonstrates the versatility of the ED technology, which can be combined with established desalination technologies. The pilot pant is installed on the site of a wastewater treatment plant. In that way, an additional option can be demonstrated where the plant used one of the ED stacks in reverse, generating electricity from the salinity difference of wastewater and seawater, while pre-desalinating the seawater.

Finally, a pilot plant with a multi-stage ED system for seawater desalination is under construction in the Netherlands.
Breakthrough innovations improving the performance of Reverse Osmosis (RO) desalination in the 1990s established this technology as the main option for most desalination purposes, overtaking the thermal technologies that were dominant up to then. At the same time electrodialysis (ED) found its way to industrial applications and a smaller specialised brackish water desalination market. In contrast with RO, the ED desalination technology has never experienced high competition between the manufacturers, keeping the prices high.

Since 2005, there has been a focus on energy generation from the salinity gradient difference and extensive R&D activities resulted in breakthrough inventions for the reverse ED process (RED) and the ion exchange membranes. These innovations have made possible the competitiveness of RED with other renewable energy technologies. In the REvivED water project, these innovations are applied to ED desalination processes and integrated concepts, leading to a revival of the ED desalination applications.

The expected impacts of the REvivED water project are
i. Contribution to overcoming the global drinking water challenge though sustainable provision of safe and affordable drinking water all over the world.
ii. Improved performance, energy efficiency and usability of high-performance water purification systems: the REvivED water project will deliver solutions that will significantly enhance the energy efficiency of water purification systems. The reduced pre-treatment requirements will also contribute to enhanced performance and usability.
iii. Benefit to the European water purification industry through new product developments: the REvivED water project will ensure that the European industry will lead in delivering solutions for water supply in rural areas of developing countries, by developing small-scale and stand-alone systems that are simple and robust, ideal for such applications.
iv. Contribution to improving innovation capacity and the integration of new knowledge: the REvivED water project will contribute to strengthen the competitiveness and growth of European companies by developing and delivering innovations, which meet the needs of Europe and global desalination markets.
v. Contribution to overcoming other environmental and socially important issues such as: energy related problems derived from the water desalination process; improved management of waste products like the so-called ‘brine’ and positive contribution to the ‘water-energy-food nexus’ issue.
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