Water. desalination + reuse

November/December 2012

Water. Desalination + reuse

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PROJECTS The Monterey Peninsula Regional Water Authority (MPRWA) in California was due to discuss and make recommendations arising from the report of consultants Separation Processes Inc on three competing seawater desalination projects for the area on 12 November 2012. The report looked at projects from California American Water (Cal-Am), the DeepWater Desal group (DWD), and the People���s Moss Landing project (PML) to replace water currently abstracted from the Carmel river which must be reduced by 60% by the end of 2016. Lack of comparable information was the main reason given by the consultant for making no decision at this stage. ���Each candidate project has attendant risk, with none considered to be disqualifying at this juncture,��� says the report. Only a balanced evaluation on a uniform set of criteria could provide the necessary information, the consultant said, and recommended the inclusion of each proponent project for full evaluation. However, the report did collect more technical information on each project than had been previously available. The most developed project would appear to be that proposed by Cal-Am, which is proposing two sizes of plant ��� 5.4 MGD (20,400 m3/d) and 9 MGD (34,000 m3/d). The consultant particularly questioned the lack of long-running experience with slant wells. DWD proposes to draw seawater through a new screened ocean intake installed at a depth of approximately 65 ft (20 m) in Monterey Bay, beneath the photic zone. The raw water would be pumped through a proprietary warming system located in an existing structure at the MLPP to increase its temperature from 8��C up to 29-35��C. The consultant expressed reservations about this ���black-box��� system ��� ���with no track record of successful operation it could prove unreliable and affect performance of the entire treatment system.��� PML is considering two alternative intake approaches - one to use an existing open intake pumping system in the Moss Landing Harbor and existing supply pipelines; and a second to modify an existing outfall and use it as a supply line drawing water from the bay, similar to the DWD intake. With either intake alternative, they propose to treat the incoming supply with single-stage granular-media filters and store the filtrate in a clear well ahead of the RO membrane process units. No details are given about the number of RO passes. The SPI report says, ���The lack of specificity in the PML treatment approach is a concern, but not considered disqualifying.��� COllabORaTiOn fOR DOw anD SwCC The Dow Chemical Company and the Saline Water Conversion Corporation (SWCC) of Saudi Arabia announced on 17 September 2012 a commercial agreement for research collaboration in desalination technologies. A pilot project will now be launched to test the suitability of innovative desalination technologies for conditions in the Arabian Gulf. The deal follows a memorandum of understanding in March 2012 between Dow and SWCC. The partners will test state-of-the-art desalination technologies developed by Dow Water & Process Solutions, evaluating their performance in the Arabian Gulf ���s unique environment, including | 24 | Desalination & Water Reuse | August-September 2012 their ability to effectively handle factors such as high salinity and high temperatures. The tests will be conducted by the Saline Water Desalination Research Institute (SWDRI) in Jubail over a period of one year. ���We are looking forward to this opportunity to test the effectiveness of Dow���s innovative ultrafiltration and reverseosmosis technologies in the conditions we work with, in the Arabian Gulf,��� said SWDRI director Ibrahim Al Tisan. ���As the sole producer of desalinated water in Saudi Arabia, we are looking at cost-effective and environmentally friendly ways to boost our operational efficiencies and the quality of our product. Our decision to partner with Dow and explore the possibility of introducing new, more effective, technologies, reflects this commitment.��� SWCC is a Saudi government body responsible for desalinating seawater to augment the supply of potable water to cities in the kingdom. It is the largest desalinated water producer in the world with 32 desalination plants that are responsible for 18% of the world���s desalinated water production. fO PlanT COMMiSSiOnED in OMan A 200 m /d forward-osmosis (FO) desalination plant has been commissioned by Modern Water at Al Najdah in the Al Wusta region of Oman. The UK company was awarded the contract worth OMR 250,000 (US$ 650,000) to build and operate the plant by Oman���s Public Authority for Electricity & Water in June 2011. Modern Water says it is the world���s first commercial FO desalination plant and the group���s second plant in Oman. The plant started producing product water at full capacity in July 2012 and during August testing was undertaken which saw the water quality exceed contractual standards. The plant is now operating commercially at full capacity, and the group has entered into the 12-month operation and maintenance phase. The Al Najdah plant is vital to the area as it supplies the local community with a much needed source of clean drinking water. Modern Water has also recruited, and is now training, a number of people from the local community who are employed as part of the site operations team. Neil McDougall, executive chairman of Modern Water plc, commented: ���The results are in line with the high expectations we set ourselves. Our unique technology greatly reduces both energy and operational costs whilst improving the quality of the water supplied. We offer a sustainable solution that has become increasingly attractive to this multi-billion dollar marketplace���. 3 auSTRalian REuSE PlanT STaRTing uP Work has begun on commissioning and testing the first stage of the membrane-based Northern Water Plant in Corio, Australia, 70 km south-west of Melbourne. The Aus$ 94 million (US$ 98 million) plant will produce 2 million m3/year Class A recycled water suitable for industrial and community use. The recycled water will replace drinking water used by the Shell refinery and be available for nearby Stead Park. The volume of effluent discharged to the ocean at the Black Rock Water Reclamation Plant will be reduced by 10%. The plant will be fully operational in early 2013, on time and on budget, says operator Barwon Water. Principal contractor was John Holland.l Latin America: where modern desalination began _________ Emilio Gabbrielli, vice president ��� business development, Toray Membrane USA Inc ___ Editor���s Note: For several years, the author, currently on D&WR���s editorial board, has enjoyed giving presentations on the history of desalination, especially for the benefit of the younger generations of desalters. They have the impression, he says, that desalination started on the continent only a few years ago, rather than more than 200 years ago. This article relies on information he has collected during his career and on some provided by expert friends like Jim Birkett. l Hermasillo l mexico city MEXICO VENEZUELA ECUADOR Amazon River BRAZIL lima ONE COUNTRY in Latin America ��� Chile ��� could be defined the father/mother of modern desalination. Land-based applications of desalination stepped up their pace in the late 19th century in several countries, but only in Chile can it be shown that desalination was already applied in several sectors (municipal, mining, railways and military) using several of the known evaporative processes - multi-effect distillation (MED), single-effect and solar. This includes the famous Las Salinas solar desalination plant, built in 1878, which operated continuously for about 50 years and also the plant serving the city of Antofagasta, which was possibly one of the largest MED plants of the times, judging from a photo taken in 1882. This should not be surprising considering the extreme dry conditions of that region. The strip of desert, which stretches for over 4,000 km from Ecuador to Chile, along the coast of the Pacific, goes through the driest parts on earth. It is much drier than the equivalent dry stretch in the northern hemisphere, which also goes for about 4,000 km, from California down to central America via Mexico. Large cities do exist on the western coast of Peru and Chile, but this is only made possible by the string of rivers that bring water from the mountain range of the Andes, which limits the desert to the east. Many areas of the desert do not see rain; it has never rained there in living memory and probably during the last millennia. This includes the capital of Peru, Lima, whose site, tradition says, was chosen as a capital of the new colony by the Spanish conquistador Pizzarro at a time when he was angry with the king and wished to choose the worst possible place. l PERU antofagasta l rio de Janeiro l l sao Paulo CHILE santiago l REGIONS MOnTEREy COnSulTanT Can���T ChOOSE Buenos aires l ARGENTINA Patagonia region DEsalination in latin amErica Although desalination by evaporation, and later by membrane processes, has continued to be applied in Chile and the whole of Latin America, it is also fair to say that this region has not been in the spotlight of desalination in the recent decades, probably due to the lack of eye-catching large applications. Instead, it has an advanced desalination community, based on many smaller-sized applications and less widely known applications than some other geographical areas, at least until very recently. As an example, one Brazilian original equipment manufacturer (OEM) alone, Perenne, in the last 15-20 years has built about 2,500 reverse-osmosis (RO) plants with capacities between 20 L/h and 20,000 m3/d, mainly for the arid north-eastern part of Brazil. Many of these plants are in very isolated areas with hardly any skilled operators. It should be noted that the dry region above is separate from the desert coastal strip along the Pacific coast. It is one of several very dry areas in a continent that appears to be well endowed with water, but does not have it where people are living. ��� November-December 2012 | Desalination & Water Reuse | 25 |

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