Parched: Can Desalination Quench the World’s Thirst?

Water_Efficiency_Editor_Laura_Sanchez

In 1790, when Thomas Jefferson was Secretary of State, he held a bottle of “purified” seawater to his lips and drank. The water in the bottle tasted only slightly better than untreated salt water, but the potential of this discovery piqued his interest.

Desalination seemed a possible solution to a myriad of problems. Jefferson enthusiastically considered the implications of this water purification innovation for military applications as well as land settlement across America. And he assembled a team of experts to test the science. Unfortunately, it was a farce and Jefferson publicly exposed the fact that Jacob Isaacks had merely used an additive to neutralize the water’s salty taste. “Mr. Isaacks’ mixture does not facilitate the separation of seawater from its salt,” Jefferson stated in a 1791 affidavit.

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Today we are faced with a different sort of desalination dilemma. There is no question that contemporary purification technology is superb and proven highly effective.  Over 18,000 plants worldwide produce nearly 23 billion gallons of water each day. Nor is there question that it could potentially supply the 1.1 billion people that lack access to clean water today. “At the moment, around 1% of the world’s population are dependent on desalinated water to meet their daily needs, but by 2025, the UN expects 14% of the world’s population to be encountering water scarcity,” predicts Christopher Gasson of Global Water Intelligence. Converting seawater to fresh, drinkable water seems like an obvious solution to our planet’s water crisis. Or is it?

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Desalination is expensive—nearly twice as costly as treating rainwater or wastewater, Professor Raphael Semiat of Technion, the Israel Institute of Technology, in Haifa, told The Guardian. By his estimate, desalination costs at about $3 per cubic meter. Other researchers echo his sentiment, indicating that maintenance is also costly, an issue particularly crucial for developing nations in which NGOs often provide initial funding, but are unable to support running costs.

Desalination is also energy-intensive, requiring 3.5 kilowatt hours of electricity to desalinate 1 cubic meter of seawater, according to Semiat’s calculations—1.3 kWh to pump seawater to the plant and 2.2 kWh for the reverse osmosis process.

And then there are environmental issues, not only with regard to the withdrawal of large volumes of seawater and the marine organisms that may be damaged at intake points, but concerning the effect of saline-concentrated effluent water on the environment that it’s released into.  

As the world’s population and global temperatures rise, pressure on our water resources increases. We’re experiencing a global water crisis while 97.5% of all of the earth’s water contains salt. What can be done to increase desalination technology’s efficiency and reduce costs?

Can desalination quench the world’s thirst?WE_bug_web

Comments
  • Jonathan McClelland.

    Wouldn’t it be better to manage our water consumption patterns more efficiently, than to develop energy sources just to manage our unwillingness to make better use of existing supplies ? There may come a time when widespread use of desalination is an important part of our survival as a species, and there certainly will continue to be isolated situations where it is a valid option, but it seems to me that we can be better stewards of our planetary support system by utilizing our energy technologies for uses that don’t have practical solutions than for ones like global fresh water supply that do have many under-utilized, low cost solutions.

    Reply
    • tlajah.

      so types the person from their lap top while carrying their cell phone both of which contain microprocessors which are produced at plants that use upwards of 4 million gallons of fresh water per day to produce. Your statement is obvious and utopian thinking. Of course we can be better stewards, but just saying it doesn’t make it happen. How do we do this, oh wise one?

      As the article states desalination is one of several strategies that will be incorporated to quench the thirst of a global population. Rain water harvest, waste water to drinking water, protecting existing sources, moving major agricultural practices out of the dry / desert climate of the US southwest, broad changes in popular diets (i.e. less meat, less processed foods, etc.) can all save and better manage our water resources. There are a myriad of potential solutions, the article is simply pointing out that desalination is not the silver bullet.

      Reply
  • Timothy Gard.

    Desalinization issues have nothing to do with cost, but need. Putting a plant on the shores of Lake Erie obviously would make no sense. But there is a more important issue in Texas for example. They have been pumping clean water from under the ground for so long, there are actually areas I am told where land elevation has changed. (not verified). And where does this waste water go to after their done with it? Into the air, which condensates over the ocean thereby reducing the oceans alkalinity, or in some cases dumped directly into rivers which empty into the ocean. And lets face it, there is a lot of fresh water running down the rivers into the oceans. There is a lot of seawater out there, and whatever desalinization we perform, mother nature will make corrections naturally. But wouldn’t it be great if we could begin returning fresh clean water to the aquifer in Texas to pay back that which was borrowed (spell “s t o l e n”) from her? I know, thats hard, and frankly I would have done the same thing they did.
    I am very interested in anyone’s opinion on this issue, and I would like to begin email communication with anyone else interested in conversation. dragmit@roadrunner.com

    Reply

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