Can we rely on seawater desalination equipment to deal with drought in the future?

Have you experienced drought? Do you notice the problem of drought is becoming more severe due to the impact of global warming?

Problem of Drought

According to the data, the drinkable water resource is valuable on the earth since we only have a tiny proportion of freshwater(3%) and the rest are the salted water/seawater (97%).

World of salt

Photo retrieved from Global Water Partnership via Flicker

Also, there is a great amount of area in the world suffer drought, and this problem is becoming severer due to the impact of climate change and global warming. The water crisis could lead to social conflicts and affect food production……

Global physical and economic water scarcity map by the United Nations World Water Development Report 4

How can we solve the problem of the drought? Let’s pay our attention to the sea, where it contains 97 PERCENT OF WATER ON THE EARTH!!!

Thus, if we can utilise the salted water from the ocean, we may save the people from the drought area?

You may want to pick the seawater desalination as a possible solution, and it does works! Countries, like Singapore and UAE, had adopted the seawater desalination technique to transfer the seawater to drinkable water.

desalination plant

Seawater desalination plant by ro plant via Flickr

Mechanism of the desalination

Currently, there are two main seawater desalination methods, namely membrane filtration and distillation. The reverse osmosis is a common technique in the membrane filtration, which passing the seawater through a smaller membrane to remove the salinity in the water. A significant amount of energy required in the process of pumping water through the membranes. The other method, distillation gain drinkable water by evaporation and condensation processes, and heat will be needed to heat the water.

An example of seawater reverse osmosis desalination retrieved from Fritzmann et al. (2007)

 

An example of evaporation-condensation desalination retrieved from Fritzmann et al. (2007)

 

Why is seawater desalination not a popular way to resolve the water crisis?

  1. The cost for building and maintaining the seawater desalination plants is expensive to some countries, especially for the developing countries. According to the data,  a desalination plant for 300 thousand people requires about 100 million U.S. dollar to build.
  2. The desalination process will produce an enormous amount of salted water as the by-product. The effluent produced in the desalination process is too salted and can impact the marine species and ecosystem, and may require further treatment.
  3. Energy is required in the desalination process. The two current major desalination methods require energy in the process and emit a considerable amount of greenhouse gases during the process. The greenhouses gases emission should be considered since the greenhouses gas will contribute to global warming and potentially cause other environmental issues.
  4. Drought is not the main problem that leads to the water crisis in some places. These areas, suffering an ‘economic water scarcity’ that is the water crisis caused by the lack of proper water infrastructures to provide drinkable water for the residents. People in the area with economic water scarcity may in the place with abundant water resource but lack the access to safe and potable water.

 

Thus, the seawater desalination cannot be a guarantee of the water source in the future at the present stage. However, technology development may allow the price of the seawater desalination installation to become affordable to more countries and to promote. Currently, improving the water infrastructures and altering water-use behaviours may be the possible ways to deal with the drought.


2 Responses to “Can we rely on seawater desalination equipment to deal with drought in the future?”

  1. yuzongc says:

    Great idea!! But I think some people are worried about the safety of the nuclear power station, especially after the crisis in Fukushima. I feel the government may need to make a lot of communications with the public to build the nuclear power plant.

  2. kdtopp says:

    Hi Ricki, this is a great summary of the desalination issue. I especially like the point that physical water scarcity is different to economic water scarcity.

    To address problem 3 in your list towards the end, there is one suggestion of how to generate clean energy quickly, cheaply, and reliably. Desalination plants are usually implemented on the coast line (funny that!) and nuclear energy plants are also usually implemented on coastlines for access to water used in their cooling systems. Nuclear energy produces abundant clean energy, and paired with a desalination plant, can produce a great deal of fresh water. Engineers and decision-makers will still need to work on the other three issues before we see desalination become a common practice.