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

Periodic Reporting for period 3 - REvivED water (Low energy solution for drinking water production by a REvival of ElectroDialysis systems)

Reporting period: 2019-05-01 to 2020-07-31

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.
Safe Water from Brackish Sources
The project began already in 2018 installing small standalone desalination systems for rural areas powered by solar energy. These novel systems incorporated new designs and technologies developed by the partners in the project and proved effective at treating brackish water of varying salinities. Although the project is now concluded, seven of these units are still operating in rural communities in East Africa and India. The efficiency, robust and simple design and remote-capable operation of these systems provides potential add-on options for incorporating further amenities that might be otherwise difficult to secure in these areas.

Electrodialysis for Seawater Desalination
A 25 cubic meter per day pilot unit using multi-stage ED is currently being successfully run with seawater at the Afsluitdijk in the Netherlands and has demonstrated the core concepts of this method. While this process shows promise for eventual implementation in the drinking water industry, the partners of REvivED water have also been examining how it might benefit industrial extraction and production technologies, many of which require fresh water for separation and other processes. Early adopters in these sectors would not only reduce the overall energy and fresh water cost of certain products, but would also help accelerate the continued development of (R)ED technology for implementation in the drinking water sector.

Integration with Established Technologies
The project came up with an electrodialysis system that can be installed as a pre-desalination step in existing reverse osmosis systems, making more drinking water from the same amount of seawater while consuming less overall energy. In 2019 the project demonstrated the potential of this arrangement through a 25 cubic meter per day seawater desalination unit that was installed in an active wastewater treatment plant, operated by the company FACSA at a seaside location in Burriana, Spain. The treated wastewater has been used to demonstrate the option of adding a reverse electrodialysis (RED) pre-desalination step. The success of this trial has shown promise for further development and several partners have discussed plans for the next steps in commercialising this technology, such as standardised manufacturing, targeted markets and expanded trials.
Brackish water systems:
The brackish water ED systems have been successfully demonstrated with 9 systems operating for extended periods in real environments, reaching TRL7. Seven of the systems are installed at remote sites in developing countries supplying drinking water to the local populations. It is estimated that over 500 people are using the installed systems. This is already an important impact that the project is proud of achieving. But the potential impact is even greater. A detailed analysis of Africa, taking into account population distribution, groundwater quality, rainfall levels and solar energy potential, concluded that up to 189 million people could benefit from the system. The report led to the identification of Ethiopia and Tanzania as the first countries to be actively targeted by follow-on commercialisation efforts. A group of partners have come together aiming to enter the market in 2 years.

Seawater desalination:
The experience from developing and operating the pilot plants, combined with the knowledge that has been generated and shared with the scientific and industrial communities, is the basis for planning the next steps in bringing the technology to the market. The main impacts can be summarised as follows:
• The pilot plants have validated the advanced models. The models can be used now for designing optimized plants that suit the specific requirements of each potential application, allowing technology developers and potential clients to make informed decisions.
• The operating plants give concrete evidence to interested parties about the potential of the technology. The robustness of the ED technology has been shown with operation under harsh conditions.
• The work of the project has increased the understanding of the ED technology potential and limitations. One of the important outcomes of the project has been to highlight the trade-offs between the energy efficiency of an ED desalination plant and the level of the capital costs.
• The market segments to target for the first sales of the ED stacks and systems have been defined. These sales will contribute to increasing the production volumes of all associated components which will contribute to driving down the prices and making ED competitive in more markets.

Other Key Exploitable results:
In addition to the complete systems, several new products have been developed. These, in combination with the increased knowledge, experience and advanced tools developed, provide the project partners and more generally the European industry with a competitive advantage in a fast-growing area. All project outcomes have been classified as Key Exploitable Results (KERs) and have been listed in the Dissemination and Exploitation Plan. These include:
• 3 integrated solutions/systems for desalination
• 3 different types of stacks
• 8 novel or improved components
• 5 software systems and models