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Seawater Desalination: Panacea or Hype?

Heather Cooley

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Although there are concerns about the commercialization of seawater desalination, such as regulation of greenhouse emissions, the technology is in use throughout the world for a wide range of purposes, including

  • providing potable fresh water for domestic and municipal purposes
  • treating water for industrial processes
  • obtaining emergency water for refugees or military operations

April 2010

CooleyArabplant.jpg

A desalination plant, hailed as being the world’s largest, was completed in May 2009 in the new Jubail II Industrial Zone in the eastern province of the Kingdom of Saudi Arabia. The plant produces 2,750 megawatts of electricity and 800,000 cubic meters of water per day. Photo: Jubail Water and Electricity Co.

One out of six people today have insufficient access to safe freshwater. Estimates suggest freshwater supplies will be a major problem for half the countries of the world by 2025 and by 2050 about 75% of the world’s population will experience a serious scarcity of the resource.1 Desalination offers the potential of an unlimited source of fresh water purified from the vast oceans of salt water. The public, politicians, and water managers continue to hope that cost-effective and environmentally safe seawater desalination will come to the rescue of water-depleted regions.
Desalination is one solution in arid places.

Seawater desalination facilities are already vital for economic development in many arid areas of the world, but there are real examples of desalination plants that have been

  • overly expensive,
  • inaccurately promoted,
  • poorly designed, or
  • inappropriately located.

Any of these may lead to a project ultimately becoming useless. It is important, therefore, to consider both the advantages and the disadvantages of seawater desalination in order to make informed choices about the appropriateness of this technology for an area.

How does desalination work?

Nature desalinates water using solar energy.

The Earth’s hydrologic cycle naturally desalinates water using solar energy. Water evaporates from oceans, lakes, and land surfaces leaving salts behind. The resulting freshwater vapor forms clouds that produce precipitation, which falls to earth as rain and snow and moves through soils, dissolving minerals and becoming increasingly salty. The oceans are salty because the natural process of evaporation, precipitation, and runoff is constantly moving salt from the land to the sea, where it builds up over time.

Heather Cooley is a Senior Research Associate with the Pacific Institute’s Water Program. Cooley holds a B.S. in Molecular Environmental Biology from University of California, Berkeley and an M.S. in Energy and Resources from UC Berkeley. Prior to coming to the Pacific Institute, Cooley worked at Lawrence Berkeley Laboratory studying climate and land use change, and carbon cycling. Her research addresses the connections between water and energy, sustainable water use and management, and the hydrologic impacts of climate change.
http://www.pacinst.org/about_us/staff_board/cooley/index.htm

Seawater Desalination: Panacea or Hype?

ActionBioscience Article

Mohamed Kassas, author of “International Water Facility,” believes a global initiative to address water shortages is urgent because about 1/3 of world’s population does not have enough drinking water and almost 1/2 of the world’s land is without water.
http://www.actionbioscience.org/environment/kassas.html

Desalination video

Sand City, CA says its new desalination plant addresses the brine issue by producing a solution left over from the reverse osmosis process that matches the salinity of Monterey Bay, where the solution is sent because it uses a special pressure exchanger. Watch how the exchanger works.
http://www.energyrecovery.com/index.cfm/0/0/32-How-It-Works.html

Desalination FAQs

Frequently asked questions, from the Texas Water Development Board.
http://www.twdb.state.tx.us/innovativewater/desal/faq.asp

Why Desalination Doesn’t Work (Yet)

With water fast becoming a hot commodity, especially in drought-prone regions with burgeoning populations, an obvious solution is to take the salt out of seawater.
http://www.livescience.com/environment/070625_desalination_membranes.html

New Approach to Water Desalination May Have Disaster Applications

A new approach to desalination being developed by researchers at MIT and in Korea could lead to small, portable desalination units that could be powered by solar cells or batteries, and this could deliver enough fresh water to supply the needs of a family or small village. As an added bonus, the system would also remove many contaminants, viruses and bacteria at the same time.
http://www.govtech.com/dc/articles/749781?utm_source=rss&utm_medium=link

Major Breakthrough With Water Desalination System

ScienceDaily (July 14, 2009)—Concern over access to clean water is no longer just an issue for the developing world, as California faces its worst drought in recorded history. With these critical issues looming large, researchers at the UCLA Henry Samueli School of Engineering and Applied Science are working to help alleviate the state’s water deficit with their new mini-mobile-modular (M3) “smart” water desalination and filtration system.
http://www.sciencedaily.com/releases/2009/07/090713144124.htm

Collection of Desalination Information Links

The Rockland Water Coalition, working to stop the United Water desalination project, has collected a large amount of information on the costs, potential environmental and health impacts, and alternatives. The site includes a the project’s Draft Environmental Impact Statement (DEIS), a collection of charts and maps, and ways that you can get involved. http://sustainablerockland.org/

International Desalination Association’s (IDA’s) Young Leaders Program

IDA’s Young Leaders Program was officially launched at the 2009 World Congress in Dubai. The goals of this exciting initiative are to help promote opportunities in the industry, support career advancement, and provide a forum for communication and the exchange of ideas among young professionals and the industry at large.
http://www.idadesal.org/t-youngleaders.aspx

100+ Ways to Conserve Water Tips

Tip #10 is: For cold drinks keep a pitcher of water in the refrigerator instead of running the tap. http://www.wateruseitwisely.com/100-ways-to-conserve/index.php

Water Science for Schools

Three interactive activity areas with a series of pages where students answer questions or give opinions. On some pages answers will be entered into a data base and, after answering, students will be shown a table of how those in other states and countries responded. Learn more from the USGS Water Science for Schools. Middle-high school.
http://ga.water.usgs.gov/edu/msac.html

Create Your Own Desalination Plant

Experiments and other activities suitable for a science fair in middle to high school grades.
http://www.swfwmd.state.fl.us/education/conservation/grades_6-12.pdf

Chemical Engineering: Desalination and Variables in Science

Experiments in removing salt from salt water to produce fresh water. From the Chemical Heritage Foundation. AP Biology and college level intro science.
http://www.chemheritage.org/classroom/chemach/engineering/engineering_student.pdf

  1. Peter Rogers. 2008. Facing the Freshwater Crisis. August 2008, Scientific American.
  2. United States Agency for International Development (USAID). 1980. The USAID Desalination Manual. Washington, DC: CH2M HILL International for the U.S. Agency for International Development.
  3. Wangnick, K. 1998. IDA Worldwide Desalting Plants Inventory, No. 15. Gnarrenburg, Germany: Wangnick Consulting for the International Desalination Association.
  4. Wangnick, K. 2002. IDA Worldwide Desalting Plants Inventory. Gnarrenburg, Germany: Wangnick Consulting for the International Desalination Association.
  5. Wangnick/GWI. 2005. Worldwide Desalting Plants Inventory. Oxford, England: Global Water Intelligence. Data provided to the Pacific Institute.
  6. As noted by the National Geographic Society, “Historically and most commonly known as the Persian Gulf, this body of water is referred to by some as the Arabian Gulf.” National Geographic Society. 2004. National Geographic Atlas of the World. Washington, DC: National Geographic.
  7. Reisner, M. 1986. Cadillac Desert: The American West and Its Disappearing Water. New York: Viking Penguin, Inc.
  8. Chaudhry, S. 2003. Unit cost of desalination. Sacramento, CA: California Desalination Task Force, California Energy Commission.
  9. National Academy of Sciences (NAS). 2008. Desalination: A National Perspective, Water Science and Technology Board. Washington, DC: National Academies Press.
  10. National Academy of Sciences (NAS). 2004. Review of the Desalination and Water Purification Technology Roadmap, Water Science and Technology Board. Washington, DC: National Academies Press.
  11. Einav, R., K. Harussi, D. Perry. 2002. The Footprint of the Desalination Processes on the Environment. Desalination 152: 141–154.
  12. Talavera, J.L.P., and J.J. Quesada Ruiz. (2001). Identification of the Mixing Processes in Brine Discharges Carried out in Barranco del Toro Beach, South of Gran Canaria (Canary Islands). Desalination 139: 277–286.

General reference: Cooley, H., P.H. Gleick, and G. Wolff. 2006. Desalination, With a Grain of Salt—A California Perspective. Oakland, CA: Pacific Institute.

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