Desalination Plant of the Year
Ras Al-Khair SWRO, Saudi Arabia
What is it?
A 68MIGD (309,128m3/d) membrane desalination installation on the Gulf coast of Saudi Arabia. It forms part of the world’s largest desalination facility, and along with a new water transportation pipeline transforms the picture for potable water in Riyadh, one of the world’s fastest-growing and most water-stressed cities.
Who is responsible?
The plant was procured and is owned and operated by Saudi Arabia’s Saline Water Conversion Corporation, the world’s largest desalination infrastructure operator. It was built under an EPC contract signed with Korean contractor Doosan, alongside civil works contractor Saudi Archirodon and design consultant Pöyry. Toyobo supplied the RO membranes, while FEDCO took responsibility for the supply of energy recovery devices.
What makes it special?
The sheer scale of the project – it is the largest membrane facility ever to be built in the Gulf, and the largest in the world to feature DAF pre-treatment – amply demonstrates that reverse osmosis can easily cope with the difficult-to-treat feedwaters of the Gulf, where high salinity and red tides are the norm. The use of heavy-duty DAF/DMF pretreatment to combat the oppressive environmental conditions proved once and for all that membrane desal is a serious contender in the GCC.
The growing confidence in, and appetite for membrane desalination in Saudi Arabia is paving the way for an energy-efficient regional desal portfolio ready to withstand the changing approach to energy generation in the Middle East. As countries diversify away from oil as a feedstock, the establishment of excellence in membrane desalination opens up further potential for exploring solar and other renewable sources of energy for desalination.
The speedy completion of the membrane element of the project, along with dedicated features like the installation of a dedicated wastewater treatment plant to deal with DAF sludge, proved that even the most complex and extensive of projects can be delivered effectively in the Kingdom. The fact that the project notched up 24 million hours of accident-free construction activity in 2014 is testament to the fact that a project’s size can easily be matched by its commitment to health and safety, and earned it a special commendation from SWCC.
Distinction
Cambria BWRO, California
What is it?
A 400gpm (2,180m3/d) brackish water treatment plant featuring a three-step treatment process: ultrafiltration, reverse osmosis, and UV/advanced oxidation.
Who is responsible?
The prime design-build contractor was CDM Smith. H2O Innovation supplied the RO and ultrafiltration units, which use Toray UF membranes and Hydranautics RO membranes. Trojan provided the UV disinfection unit. The client is the Cambria Community Service District.
What makes it special?
A 50-gallon-per-day consumption limit for local residents, a long-standing moratorium on new water connections, and a ban on the outdoor use of potable water meant that the coastal community of Cambria (pop. 6,000) ranked among the worst casualties of California’s raging drought. Although the city had looked at seawater desalination before, Governor Brown’s declaration of a drought emergency freed up the possibility of developing an alternative brackish water option, which was exempt from a burdensome environmental review process, enabling it to move ahead in record time.
Fast-tracking the construction of a desalination project such as this is unprecedented in California, and sets a new benchmark for what is achievable in the face of severe water stress. Following the decision to move ahead in January 2014, an emergency coastal development permit was granted in May, and construction began in August. The use of pre-fabricated processing units and above-ground plumbing reduced the capital cost, and ensured that the plant was granted an operational permit in November 2014 – less than a year after the process began.
The feedwater is a unique mix of groundwater, brackish water and secondary treated effluent, and the two-stage RO system results in a 92% permeate recovery rate – close to double that of a standard seawater desalination plant. The high level of acceptance from local residents for what is ultimately an indirect potable reuse project conclusively demonstrates that Californians are willing to retain their pioneering spirit when faced with long odds.
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