Harmonious cities - UN-Habitat

Perth Lord Mayor Lisa Scaffidi defends the
new plant as one of the first in the world to be
entirely powered by renewable energy, sourcing
electricity from a wind farm.
“We have also began an intensive monitoring
programme to gauge the impact on the
bay in which the studies have so far found
that there will be no adverse ecological effects,”
she confirms.
Spain, with the largest number of desalination
plants outside the Middle East, has also
focused on improving energy efficiency in its
plants. Previously they would use 18kw/h to
produce 1 cubic metre of water. Now, its newest
plant in Barcelona, due to be completed
next year will use only 3kw/h per cubic metre
of water, 45 percent of which will be solar
power.
The fact that there have been no long-term
studies on the environmental impact concerns
Pittock from the WWF. “As with any
relatively new engineering, such as large
dams that grew up in the 1950s, the negatives
become known when it is too late or too expensive
to fix. What we need most is a new
attitude to water not unchecked expansion of
water engineering.”
Other less harmful technologies and water
systems may also lose out to the big promises
of desalination. Melbourne, Australia,
will see one of the largest desalination plants
built on its shores. Already the city provides
tax rebates and statutes that require all new
housing to have either a rainwater tank or
solar hot water system. Many argue now that
these rainwater tanks will be obsolete and
unnecessary after the plant is built, which
will eventually provide up to 150 billion litres
of water a year.
Melbourne University scientist, Peter
Coombes, believes that rainwater tanks have
the potential to provide between 80 billion
and 120 billion litres of water a year for the
city and at a lesser cost.
Although his reports do not say it, their implication
is that an alternative water strategy
could save taxpayers and homebuyers money
by reducing reliance on expensive public water
facilities, such as desalination plants.
“There is a window of opportunity to refocus
Melbourne as a sustainable city, which
includes rainwater harvesting, waste water
recycling and water/energy efficiency and we
cannot lose this chance by pursuing silver
bullets from a narrow economic perspective,”
says Coombes.
Even London, with its wet and rainy image,
has needed to turn to this technology due to
ever increasing pressures on its water supply,
albeit after a lengthy court battle after the exmayor
of London, Ken Livingston opposed it.
Ken Livingston’s argument was that it was
senseless to consume vast amounts of energy
to treat brackish river water when 790
million litres of drinking water is lost everyday
in London due to leaky water pipes. Five
times the amount the plant will produce.
“They (Thames Water) should invest more in
Water
IN-FOCUS
repairing pipes and harvesting rain,” he said.
“There is no need for a desalination plant as
with improved demand, leakage and resource
management, it would be possible to ensure
adequate water supplies for London without
it.”
Despite these concerns, more and more cities
are increasingly turning to desalination
plants. In California alone some 20 seawater
desalination plants have been proposed, including
a USD 300 million facility near San
Diego.
China, India, and Africa with rapidly growing
middle classes, are building more and
more desalination plants to meet demands
from growing industries and have even moved
into the technological research of plants.
Water-starved Chennai, on India’s southeast
coast, will soon host the country’s largest
desalination plant, where the city’s water
requirements are expected to double by mid-
2031. This year Algeria opened the largest de-
Many new plants are entirely powered by renewable energy Ph o t o © WAt e r Co r P o r A t i o n
salination plant in Africa to provide water to
one million residents in the capital.
Not all plants are designed or limited to
large urban centres. Ksar Ghilène is an isolated
Tunisian village of 300 inhabitants in the
Saharan desert. Drinking water is supplied to
the village through the use of a brackish water
reverse osmosis desalination plant driven
by photovoltaic solar energy. After two years
of operation the plant has successfully produced
more than five million litres of fresh
water. u
u r b a n
November 2008 WORLD 29