Harmonious cities - UN-Habitat

IN-FOCUS Water
The impact of
desalination in the
Middle East and Asia
It is a cruel irony that 71 percent of the Earth’s surface is covered by water, yet only a small
percentage of this is drinkable. But, as Jonathan Andrews reveals, with developments in
desalination technology, what was once a prohibitively expensive process restricted only to
oil-rich nations, has become an affordable option for many cities.
The International Desalination Association
(IDA) states that there
are now 13,080 desalination plants
in operation around the world in almost 100
countries. This may seem a sizeable amount,
yet the plants only produce 0.5 percent of
global water use. Almost half of these plants
are found in the Middle East, where energy is
cheap and water scarce. But many other cities
in the US, Australia, Spain, India, Africa and
China are now turning to the technology to
meet growing demands.
Historically, there has always been a human
interest or dream of turning the abundance
of salt water into drinkable water. The
realisation of this began during World War
II, when military establishments operating in
arid areas needed a way to supply their troops
with potable water and developed very basic
models.
The movement took a giant step forwards
in the 1950s and 1960s when the US government,
at the behest of President John
Kennedy, established the Office of Saline
Water and then later the Office of Water Research
and Technology in a major effort to
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November 2008
Lisa Henthorne, President of the IDA
Photo © idA
develop the industry. At the same time the
Middle East was discovering the advantages
of its vast oil fields and the potential of desalination.
“Previously, the high costs associated with
desalination hindered interest in abundantly
available seawater as a potential water source.”
– Karen Dobson, Dow Water Solutions
“Desalination took off in the Middle East,
due to a complete lack of water,” explains Lisa
Henthorne, President of the IDA. “When it
realised the potential of its huge fossil fuel
resources, thermal desalination plants were
built alongside power plants.”
This simple concept involved using the heat
from the power plants to boil water, collect
the steam and then condense it to make pure
water. “It was relatively efficient, because it
used the waste heat to create the water,” adds
Henthorne.
Advancements in membrane technology,
that is necessary in the reverse osmosis process
involved in some desalination plants, have
increased dramatically in the past 30 years.
Reduced energy use, lower overall treatment
costs, and raised water quality all make it an
attractive alternative.
“They have broader applications to countries
that don’t have the resources of fossil
fuel like the Middle East; they use less energy
and don’t need to be co-generated next to
power plants,” explains Henthorne.
Perth, on the drought-ridden western coast
of Australia, is one city that has not traditionally
been a market for desalination, but has
recently built the largest plant in the southern
hemisphere.
Dow Water Solutions, a desalination company
whose reverse osmosis technology is at
the heart of the Perth plant, believes its appeal
is increasing.
“Previously, the high costs associated
with desalination hindered interest in abundantly
available seawater as a potential water
source,” says Karen Dobson from Dow Water
Solutions. “The successful operation of the
Perth plant is further proof that we have in