Background Exploitation of freshwater resources has led to a shortage of quality freshwater in many low-density European regions. Islands, for example, lack freshwater availability and access to renewable energy sources. In South Mediterranean regions additional problems arise from saline intrusion, soil contamination and erosion, further diminishing groundwater supplies. Desalination plants have been developed to deal with water shortage problems in the Cycladic Islands. This process produces a clean water product, and a concentrated brine that requires disposal. However, disposal of the brine, which is estimated to be twice as salty as seawater, causes significant pressure to aquatic organisms. Furthermore, desalination is energy intensive and energy can be expensive for island communities. Objectives The SOL-BRINE project aimed to develop a solar–driven brine treatment system in order to eliminate the current practice of brine disposal. The development of such a system is an innovative approach to finding a feasible solution to brine elimination. The proposed SOL-BRINE prototype system for brine treatment will produce two by-products: dry salt, which can be easily handled and used commercially, and water to be used for irrigation or other purposes. Results The SOL-BRINE project developed a solar–powered brine treatment system, designed to eliminate the current practice of brine disposal into aquatic environments. This brings added value in that the significant environmental problem of brine disposal can be solved, while at the same time marketable products (salt and water) can be generated. The project’s energy-autonomous brine treatment system is in operation on Tinos, a Greek island situated in the Aegean Sea within the Cyclades archipelago, at the existing desalination plant in the Agios Fokas area. The energy-autonomous brine treatment system comprises an evaporator, a crystalliser, and a dryer. It recovers high-quality water with the potential of variable water uses (including also industrial use) and solid salts. The project team is currently investigating possibilities to separate these salts in order to obtain commercial products, therefore promoting a circular economy. The project connected the Photovoltaic (PV) panel, and arranged the components, to optimise the operational efficiency of the system. It was shown that its demonstration prototype could be replicated at full-scale in Tinos or in other regions with similar characteristics. The potential is high, given that there are approximately 45 desalination units in Greece alone, and many other units elsewhere in Europe. Market opportunities in Greece were assessed during the project. A lot of Greek areas are water deficient and significant environmental, economic and social benefits could be attained, especially on islands with drinking water scarcity and power availability issues. What is more, one of the project findings was that the technology can also be applied for similar saline-impaired wastewater streams originating from other industries (such as chemical industries). Direct environmental benefits achieved by the project in the short-term included the treatment of approximately 200 tonnes of brine; the production of 180 m3 of distillate water; the production of 12 tonnes of edible salt (which is no longer disposed of into the sea). The unit produces around 77 000 KWh of thermal energy and 5 000 kWh of electricity through renewable solar energy, saving over 94 tonnes of carbon dioxide (CO2) equivalent greenhouse gas emissions compared to units powered by fossil fuel. The management of brine implements the Water Supply and Sanitation Technology Platform (WssTP) of the European Commission, which recognised the need for more R&D in this field. Even though the need for Zero Liquid Discharge from the desalination sector has been long-recognised as a promising eco-innovative water solution, the SOL-BRINE system comprises the only advanced technology - in terms of its Technology Readiness Level (TRL) - that can provide a near-market solution to the complex issue of sustainable brine handling. It comprises the first-of-its kind in scale and scope, and can provide a complete and viable opportunity for environmental protection and resource recovery in the fast-growing desalination sector. SOL-BRINE therefore offers a unique opportunity to accelerate the commercialisation of the Zero Liquid Discharge Desalination approach. A number of socio-economic benefits derived from the cost savings of operating the innovative desalination unit. Less pumping is required compared to existing units, as the recovery ratio is increased from some 30% to over 90%. The cost of piping the brine discharge to the sea is removed, as is the cost of pumping and dispersion equipment for that purpose. Lower-cost land, away from the coast, can be purchased for the desalination unit, as no infrastructure is required for brine discharge. This also reduces the environmental impact on the coastal landscape, with benefits for tourist and other activities (desalination plants have in the past received strong social opposition due to their ‘aesthetic pollution’). In business terms, uptake of the SOL-BRINE technology would contribute to the greening of desalination, with associated wealth creation and employment opportunities in the long-term, due to the closed-loop system recovering significant amounts of marketable resources. It could be installed as end-of-pipe equipment at existing coastal or inland desalination plants, practically with no restrictions, and can treat all kinds of water source (seawater or brackish water). Water scarcity and droughts already affect one third of the EU territory. In theory, desalination can deliver unlimited amount of freshwater, but in practice there are currently limitations in terms of high-energy requirements and negative environmental impacts. The new technology helps shift the balance by making desalination greener and more cost-effective, to the benefit of local economies. The project was awarded the first prize in the Blue Growth Piraeus Competition (the prize was awarded by the Commissioner Mr. Karmenu Vella during the European Maritime Day on 28 March 2015), receiving incubation support and coaching for creating a start-up company, while an SME project was granted (Project No. 674455 – GReen Desalination) with the objective to develop a strategic business plan. Finally, a start-up company was established in November 2015, which was selected out of 15 000 companies, to participate in the world-class accelerator program STARTUPBOOTCAMP HIGH TECH XL in Eindhoven, the Netherlands. The start-up company is called SEALEAU and has already received customer traction in the Netherlands by scaling-up the SOL-BRINE technology. It also conceived and prepared the ZERO BRINE proposal, with the aim of developing a circular economy approach for the re-use of metals and minerals recovered from brine effluents, under the European Commission’s Horizon 2020 programme. SEALEAU will be the technical coordinator of this project, with the Institute of Sustainable Process Technology (ISPT) as overall coordinator. Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).