Water. Desalination + reuse
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PROJECTS | 22 | Desalination & Water Reuse | February-March 2016 VEOlia TOPS TaRgETS in MaSdaR dESalinaTiOn PilOT PROgRaMME Interim findings by engineering giant, Veolia, from trials designed to up efficiency and develop renewable energy-driven desalination have already outstripped the trial's energy reduction targets the company has reported. The Veolia pilot plant is part of a series of collaborations between industry players and the Abu Dhabi Future Energy Company, Masdar. The projects share the ambition to reduce energy consumption using green energy sources. Veolia has been taking part in Masdar's Renewable Energy Water Desalination Programme through its desalination arm, Sidem. Veolia said its plant has shaved 7% from the contractual target initially required by Masdar. Under the terms of the competition the participants each have a target of less than 3.6 kWh/m³ – an average non-renewable energy desalination plant runs at about 5 kWh/m³. Sidem claimed its operational reduction would add to a 25% reduction in civil works from a new pre-treatment design which makes the plant smaller and cuts capital outlay. Sidem has been producing potable water since August. The pilot works under large-plant constraints and, according to Sidem, is capable of handling exceptionally demanding seawater with salinity up to 52 g/l, at temperatures of up to 42°C and with the threat of harmful algal blooms. "Although these are all new technologies, their development is advanced enough to consider them ready for large-scale implementation. The upcoming optimization phase will allow Veolia experts to push the limits of their system to enhance the design and processes, in the pursuit of even better power efficiency while extending the lifetime of the plant," said Veolia. Technologies used in the trial include high-performance seawater pre-treatment, combining air floatation and filtration, energy recovery devices, and a new osmosis membrane feed configuration able to deal with high treatment fluxes. The long-term goal of the Masdar project is to implement renewable energy- powered desalination plants in the United Arab Emirates and the rest of the Middle East North Africa region and to have a commercial-scale facility operating by 2020. Four commercial partners – Abengoa, Suez Environnement, Trevi Systems and Veolia won places on the programme. They are each developing an innovative pilot seawater desalination plant. Their membrane-based projects at Al Ghantoot have a combined capacity of 1,500 m³/d. The project enables the participants to test the viability of powering desalination stations through renewable energy. The test-site uses solar energy for the heating stage of desalination, but it is the second stage – osmosis – which the companies are aiming to refine. And each participant is aiming to make use of the by-products in the brine effluent. dEVElOPER REJECTS ClaiMS ThaT hunTingdOn PROJECT COuld faCE flOOd RiSk The developer behind a proposed desalination project at Huntington Beach, California has rejected claims that high tides over the Christmas weekend could signal a surge in flood protection costs for the plant. The site designated for Poseidon Water's planned giant Huntingdon Beach seawater desalination plant – alongside an existing AES natural-gas power plant – was among a number identified by a 2009 Pacific Institute study as prone to a 100-year flood - facing a 1% chance in any year of flooding. December's 2m tides have prompted warnings for the desalination project developers. According to a report in the Los Angeles Times, water programme director for the Pacific Institute, Heather Cooley, said she believes the increased sea level should prompt Poseidon to increase the flood protection at the proposed Huntingdon Beach desalination facility. She warned that the higher levels could create a need for changes to the plant's intake system. According to Cooley, rising seas could change the dynamics of the region's tides. "There could be changes in erosion patterns that could create problems for existing infrastructure, especially if it's not designed to accommodate those changes." Poseidon insisted the site will be unaffected by sea-level rises during the desalination plant's 50-year operation cycle. Poseidon's vice president, Scott Maloni, said the sea-level rise does not pose a risk to the facility according to guidance produced by the California Coastal Commission. "We have applied the [Coastal Commission] staff 's worst-case sea-level rise estimates to our analysis. The worst-case sea-level rise projection in the year 2070 is 3.5 feet [mean sea level]. The desalination project current sits at 9 to 14 feet, so 3.5 feet of sea level rise doesn't pose a risk at this time," Maloni said. Associate director of Orange County Coastkeeper, Ray Hiemstra, forecast that the series of extraordinarily high tides was, in time, "going to be a normal day". "The tides that we saw last weekend are an example of what we're going to be looking at in the future," Hiemstra said. "Throw in big waves or a storm on top of that, we're going to have some real interesting situations," he added. He said that billion-dollar desalination projects like Huntingdon Beach should not be built in an area that is already prone to flooding. He suggested that the project be moved to another location, possibly Doheny State Beach. auSTRalian iSland RigS uP SOlaR-POwEREd dESalinaTiOn Rottnest Island, off the Western Australia coast, is constructing a solar power source for the island's population including its desalination plant. The A$ 7.3 million (US$ 5.3 million) project combines photovoltaics with a sophisticated control system to optimise the use of the renewable resource in running the desalination facility. It will displace diesel-powered generators running on imported fuel according to a report in Cogeneration magazine. A Hydro Tasmania spokesman said: "A novel aspect of this project is its focus on controlling the timing of an energy- intensive activity – running the island's desalination plant – to make the best use of renewable energy when it is most abundant. Running the plant on renewables rather than diesel will reduce the cost and emissions intensity of producing the island's drinking water." Seven diesel gensets and a 600 kW wind turbine installed in 2004 have met the island's 5 GWh annual power demand to date. The Rottnest Island Water and Renewable Energy Nexus Project will add 600 kW of solar power and an advanced control system designed to maximize use of renewable energy for desalination according to Cogeneration. The Australian Renewable Energy Agency will provide up to A$ 4.8 million (US$ 3.5 million) in funding towards the project which is scheduled for completion by May 2017.