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Water Desalination
Desalination Expands as Technology Becomes More Affordable
by Xanthe Webb Aintablian
Contributing Writer
Desalination (also spelled desalinization) is the process of creating
fresh water by removing saline (salt) from bodies of salt water.
There are varying degrees of salinity in water, which affects the
difficulty and expense of treatment, and the level of saline is typically
measured in parts per million (ppm).
The U.S. Geological Survey provides an outline of what constitutes
saline water:
1,000 ppm – 3,000 ppm is low salinity,
3,000 ppm – 10,000 ppm is moderate salinity, and
10,000 ppm – 35,000 ppm is high salinity.
Water that contains saline levels less than 1,000 ppm is generally
considered fresh water and is safe to drink and use for household and
agricultural purposes.
For a reference point, typical ocean water contains about 35,000 ppm,
the Great Salt Lake contains variations of 50,000 – 270,000 ppm, and the
Caspian Sea contains an average of about 12,000 ppm.
The more concentrated saline is in a body of water, the more energy
and effort it takes to desalinize it.
Desalination Processes
Reverse Osmosis
There are several setbacks of reverse osmosis. The membranes are
currently prone to gather too much bacteria and “clog up,” although they have
improved since they were first used.
The membranes deteriorate when chlorine is used to treat the bacteria.
Other setbacks are the arguable water quality that reverse osmosis
produces, along with the considerable pre-treatment that the salt water
requires.
Forward Osmosis
The main setback to forward osmosis is that it has great potential,
but is still fairly new to large-scale desalination and therefore needs funding
and research to explore the possibilities that could improve it and reduce
energy costs.
Electrodialysis
Thermal Desalination
Multistage Flash Distillation
Multiple-Effect Distillation
Negatives of Desalination
Geography of Desalination
Saudi Arabia is currently the world’s number one producer of
desalinated water.
They use multi-flash distillation in several large plants, providing
water for many large cities, including the largest city, Riyadh, situated
hundreds of miles from the coast.
In the United States, the largest desalination plant is located in
Tampa Bay, Florida, though it has a very small output compared to most
facilities in the Middle East.
Other states that are developing plans for large desalination plants
include California and Texas.
The United States need for desalination plants is not as severe as
many other countries, but as the population continues to explode in dry,
coastal areas, the need increases.
Future Options of Desalination
Desalination is a process primarily done in developed countries with
enough money and resources.
If technology continues to produce new methods and better solutions to
the issues that exist today, there would be a whole new water resource for more
and more countries that are facing drought, competition for water, and
overpopulation.
Though there are concerns in the scientific world about replacing our
current overuse of water with complete reliance on seawater, it would
undoubtedly be at least an option for many people struggling to survive or
maintain their standard of living.
Xanthe Webb Aintablian
Writing and Editing Professional
Winchester, Virginia
I am a professional writer and editor. I like
to work hard, think critically, and build relationships. I enjoy outdoor
adventure and learning about nature, geography, and science.
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