Water. Desalination + reuse
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30 In Site September 2016 Water. desalination + reuse Abengoa combines RO and brine treatment 2 The pilot from Abengoa is using a combination approach whereby reverse osmosis is the core process, augmented by membrane distillation as a brine treatment process. The budget for the plant was $7.9 million. Abengoa is a leader in solar power, but has this year sold four photovoltaic plants in Spain as part of a divestment policy. In August, the company completed a financial restructuring, with new loans totalling €1.2 billion ($1.3 billion). Veolia-Sidem tests a trio of innovations 3 Veolia-Sidem's pilot is designed to assess three innovations: a pre-treatment system that combines flotation and filtration; an energy recovery device; and a new membrane feed configuration that optimises distribution of the fluxes in the membranes. The plant has beaten Masdar Clean Energy's target of 3.6 kilowatt hours for each cubic meter of water, reducing it by 7 per cent to 3.3kWh/m3. The biggest challenge was developing a new energy recovery device, a project that Veolia-Sidem is working on with specialist manufacturer from Switzerland, Osmorec. "The energy recovery market is competitive, and every percentage of performance gained can lead to huge savings in operation costs," says Henri Casalis, project manager, Sidem. Veolia-Sidem claims that the energy recovery device is 1 to 2 per cent more efficient than existing technologies. "We're improving on our results every day," says Casalis. "Additional to energy cost savings, our new pre-treatment design can save 25 per cent on engineering, cutting capital expenditure, and reducing the plant's overall footprint. We expect to improve further on these performances during the optimisation period, and we're excited to find out how far we can go." Veolia-Sidem's approach to the construction and development of the pilot plant was to treat it like a real-life infrastructure project. "One of the great advantages that Veolia has in understanding its own designs, and the suitability of the whole concept of a desalination plant in a defined technical and economic environment, is our dual competence, and experience, as a design and build contractor, and a plant operator," says Casalis. "We've learned a lot about the technologies we implemented, and we'll continue to push them to their limits during the optimisation period. The main goal is to be able to offer them, and to guarantee their performance on huge desalination projects." Casalis adds that while the technologies tested are new, they are "not experimental, they will not require another five or 10 years to be implemented on a large scale plant". Trevi Systems is unique in trialling forward osmosis 4 Trevi Systems is the only company trialling a forward osmosis system as part of the Masdar Clean Energy pilot series, using technologies developed to handle difficult waters. "Trevi Systems has a technology that is ideal for difficult water, and we're running it with seawater, which is not difficult, but the value of the technology is that it can be applied to a more challenging water than seawater, such as the high saline groundwater that we have in the United Arab Emirates, which RO cannot handle," says Dr Alexander Ritschel, head of technology, Masdar Clean Energy. Ritschel describes Trevi Systems' approach as "the most innovative by far, because it is a totally new concept of water treatment". The results so far are "very good", he adds, and the project is continuing to develop and to refine its processes to respond to the local conditions. "Very soon, new membranes, and new heat recovery systems will be installed, so this is a very, very interesting process that has the potential to become a technology for difficult feedwater," says Ritschel. Trevi Systems is focused on developing forward osmosis systems that operate at a lower pressure and use less energy than conventional RO systems. We've learned a lot, and will con- tinue to push the technologies to their limits during the optimisation period. Henri Casalis, project manager for Mas- dar, Sidem Right: The budget for Abengoa's plant in Ghantoot was $7.9 million