By Fabien Creus and Sanjeev Unni

Introduction
The Middle East and North Africa (MENA) is the most water-scarce region of the world (see Figure 1). Approximately 6.3 percent of the world’s population resides in these areas, while the region only safeguards 1.4 percent of the world’s renewable fresh water. For decades, the region has dealt with an increasing demand for water, exacerbated by rapid population growth, mass urbanization, depleting natural resources and the effects of climate change. The challenge for optimizing water management remains an important priority across the region. Water is a vital commodity needed for energy generation, residential needs, as well as commercial and industrial operations. Increasing water scarcity has driven companies to seek out both time-tested and new ways to purify water and promote water reuse that are both cost-effective and offer an improved environmental profile.

Figure 1. Global freshwater availability (2007)

Source: FAO, United Nations and World Resources Institute

Old problems, innovative solutions
As Middle Eastern economies grow and communities reach higher levels of affluence, the demand for residential and commercial water has increased. Thus, a variety of strategies have been implemented to promote effective water management, from water conservation policies and desalination solutions to water importation and innovative filtration technologies. In order to mitigate the challenges of untreated effluent and sewage that contaminate surface, ground and sea waters, UF and RO technologies have been developed to remove impurities, bacteria and viruses from wastewater. In this scenario, wastewater is filtered and processed to be reused for a variety of purposes and applications, including irrigation and domestic or industrial use, allowing commercial and residential entities to extend the life of limited freshwater supplies.

Park Hyatt filtration system
RO and UF have had a long and successful history. By separating salt and other impurities from water at the molecular level, reverse osmosis comprises the finest level of filtration available. The reverse osmosis membrane is a nano-structured composite that is fabricated into commercially viable modules, which are in turn the building block of modern RO systems. Ultrafiltration, on the other hand, uses a pressure-driven membrane separation process that removes suspended particles and turbidity. This high-recovery technology is often used in pretreatment for RO and as a barrier technology to remove suspended solids, bacteria, viruses and some organics.

Park Hyatt UF and RO elements

Case study
For years, a hotel in Dubai, United Arab Emirates, was operating its HVAC cooling system using a potable water supply from the local municipality to cool the hotel’s 225 luxury rooms and suites. The water was high in TDS, which limited the number of cooling cycles available, resulting in high operating costs. In 2010, the hotel initiated a new water recycling project to supply their cooling towers with reused water (see Table 1). Based on the past success of a similar ultrafiltration project implemented by a water and processing solutions company to treat wastewater at a dairy farm in Dubai, the hotel approached an OEM to provide technical solutions to polish the municipality’s treated sewage effluent (TSE) to use for their cooling tower (see Figure 2).

In selecting their new filtration system, the hotel wanted to reduce the consumption of potable water, averaging 400 m3 per day, improve water quality and reduce operating costs. The hotel’s main concern was the health and safety of hotel guests and staff, so the system had to effectively eliminate odor, suspended solids and bacteria from TSE water. Furthermore, the hotel required that the selected technology was a fully automated system, minimized water wasted during the backwash process, and that the system filters were easy to operate and maintain. In meeting this water quality and quantity challenge, a pretreatment phase using UF membrane technology, followed by a purification phase using RO membrane elements, was selected to decontaminate the sewage effluent and provide high-quality water for the hotel’s cooling system. The hotel chose the same water and processing solutions company to provide the filtration system due to their knowledge and experience in conventional pretreatment through membrane technology. When installing the new filtration system, the water and processing solutions company tested the water quality from the TSE supply and selected the best operating conditions for the UF and RO.

Conclusion
The hotel’s combined membrane system filters and processes 148,300 cubic meters of water annually. The UF and RO filtration process has resulted in high-quality water, low in TDS (an RO system analysis for the membranes is given in Figure 4). The filtration system not only removes wastewater contaminants, but has helped the hotel reduce the consumption of potable water and improved the efficiency and cost-effectiveness of the cooling system. Since the hotel implemented the UF and RO filtration system, it has saved as much has 358,880 cubic meters of potable water by using polished treated sewage effluent. The amount of potable water saved by the water recycling project is equivalent to the capacity of 143 Olympic-sized swimming pools. The product water from the RO system is given in Table 1.

References

  1. Roudi-Fahimi, Farzaneh, Liz Creel, and Roger-Mark De Souza. 2002. Finding the Bal- ance: Population and water Scarcity in the Middle East and North Africa. Washington, DC: Population Reference Bureau.
  2. Abdel-Dayem, Safwat, Faisal Taha, and Redouane Choukr-Allah. Water Reuse in the Arab World: From Principle to Practice. Rep. The World Bank, The Arab Water Council, 22 May 2011. Web. 19 Aug. 2013.
  3. The amount of TDS in the municipality’s potable water was in the range of 120-140 ppm.
  4. Al Ain Dairy farm uses RO and ultrafiltration technology from the water and process solutions company to keep the farm’s 2,500 cows cool, as well as for irrigation and cleaning purposes. The system saves the farm as much as 300,000 cubic meters of water per year.
  5. Sand filtration followed by reverse osmosis.
  6. The average volume of an Olympic-sized swimming pool is 2,500 cubic meters. The hotel has saved 358,880 cubic meters of potable water to date.

About the authors
Fabien Creus is the Market Development Manager at Dow Water and Process Solutions. He can be contacted by email fcreus@dow.com or by phone +49 7227913816. Sanjeev Unni is the Sales & Technical Manager, Gulf Cooperative Council (GCC) at Dow Water & Process Solutions. He can be contacted by email sunni@dow.com or by phone +971 4 4537041.

 About the company
The global leader in sustainable separation and purification technology, Dow Water & Process Solutions (DW&PS) is making a clear impact in the world, helping to make water safer and more accessible, food taste better, pharmaceuticals more effective and industries more efficient and spearheading the development of sustainable technologies that integrate water and energy requirements. DW&PS offers a broad portfolio of ion exchange resins, RO and UF membranes, fine-particle filters and electrodeionization products, with strong positions in a number of major application areas, including industrial and municipal water, industrial processes, pharmaceuticals, power, residential water and waste and water reuse.

About the technology
DOW™ ultrafiltration membrane technology is the ultimate barrier for reducing suspended solids and pathogens to protect the water treatment process. The system’s pressurized, outside-in configuration is able to handle high suspended solids, minimizing pretreatment and lowering capital cost. Furthermore, the hydrophilic, PVDF double-wall hollow fiber reduces fouling and has excellent chemical resistance and added strength, resulting in durable, long membrane life. The fine pores (0.03 μm) effectively reduce pathogens, most viruses, bacteria, colloids, silt and other suspended matter, facilitating long-term stable operation. DOW FILMTEC™ RO membrane elements offer high flux and outstanding quality water for applications requiring sanitary-grade membrane elements. The full-fit configuration minimizes stagnant areas and is optimal for applications requiring a sanitary design. All components comply with FDA standards.

About the OEM
Veolia Water Solutions & Technologies is the world leader in desalination, municipal, industrial water and wastewater treatment, offering total expertise in the field and a comprehensive range of technologies and services. It is both a leading EPC Design & Build company and a specialized provider of technological solutions. VWS is a subsidiary of Veolia Environment, France, a Global Fortune 500 worldwide company with an annual turnover exceeding 36 billion Euros and a presence in over 100 countries.

About the hotel
Park Hyatt provides discerning, affluent individual business and leisure guests with elegant and luxurious accommodations. Guests of Park Hyatt receive highly attentive personal service in an intimate environment. Located in many of the world’s premier destinations, each Park Hyatt is custom designed to combine sophistication with distinctive regional character. Park Hyatt features well-appointed guestrooms, meeting and special event spaces for smaller groups, critically acclaimed art, as well as food and beverage programs, and signature restaurants featuring award-winning chefs.

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