Transcript Desalination - tfss-g4p

Presentation by Group 7
Areas of Investigation
 Background – What is desalination?
 Ethical implications
 Economic implications
 Environmental implications
 Social implications
 Political implications
Our mission
As a group of individuals with
different science backgrounds,
we hope to help create a
better understanding of
desalination.
WHAT IS
DESALINATION?
Desalination
 Desalination is the removal of an amount of salt (sodium)
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or other various minerals from water.
This is mainly used to remove sea salt water to fresh
water, making it suitable for human consumption
The process of desalination is not very energy-effective,
and consumes large amounts of energy and resources
Desalination can be used in small scale situations, such as
on submarines and ships to provide fresh-water for it’s
occupants
Many by-products are produced from desalination, most
commonly table salt
Desalination Continued
 The largest desalination plant is in the UAE (United Arab
Emirates), which produces 300 million cub meters of
fresh-water annually
 The second largest, is located in Tampa Bay, and only
produces roughly one eighth fresh-water as the plant in
the UAE
 Especially useful for irrigation systems, as it can be
extremely beneficial for third-world countries and
distributed quickly
Reverse Osmosis
 Most commonly used method
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of desalination
Removes salt and other
minerals
Pressure is used to drive water
through a membrane, leaving
behind brine
Costs associated with reverse
osmosis are mainly for
electricity, membrane
replacement and labour
Brine must be carefully
disposed to avoid deleterious
environmental impacts
Electrodialysis
 Another common method of
desalination
 Uses an electrical potential
to drive ions through a
membrane leaving water
behind
 Membrane attracts salt ions
leaving behind clean water
 Considerably expensive
compared to other methods
Distillation
 Not very common method
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of desalination
Saline water heated to
produce water vapour
Vapour condensed to
produce freshwater
Relatively expensive method
of obtaining fresh water
Aside from brine, has
minimal environmental
impacts
ETHICAL
IMPLICATIONS
Seems like an interesting idea
with pros and cons, but how
does its use effect living
creatures around us ethically.
Costly Savings
 To save costs, some companies dump
waste brine into oceans and streams,
contaminating and destroying
ecosystems
 Some plants use fossil fuels to power
themselves
 Can be costly, the poorer regions that
need the water the most may not be
able to afford it
The Hope
FIX THOSE ISSUES!
 new “Zero Liquid Discharge”
technology ensures no brine
released, but stored or
sold=Boost for efficiency!
 With proper designing, power
plant waste heat can be
combined to power desalination
plants
 Each year, new technology
allows for cheaper and cheaper
desalinated water
The Pros
 WATER FOR ALL!
-1/5 of the water does not have access to
clean drinking water, (CNA) This can be
changed!
 SAVE OUR STREAMS
-2.5% of earths water is freshwater, the
vast majority is unusable ice/glaciers
-all humans and non-ocean animals share
the remaining fraction for all our uses and
we’re running out!
-Desalination makes use of the other 97.5%
of water, : THATS A LOT OF WATER! (NRC)
END THE CONFLICT
-no more conflicts over freshwater, no
more lawsuits, more living with a common
humanity!
-Water can be available to all!
Providing clean water to
earthquake victims without
proper access, globalgiving.org
ECONOMIC
IMPLICATIONS
Economic Effects
 Desalination reduces
reliance on importing water.
 This is a major cost to a
nation- fresh water will
always have demand from
all members of the
population.
 This is notoriously expensive
to continue; for example the
cost of 1 bottle of water:
$1.50 USD per Litre or
$1,500 USD/m³
 Desalinated water, costs
US$0.75 - 6.00/m³
Economic Effects
 Another key aspect of
Desalination is that it allows
economic activity to remain
unaffected by seasonal
conditions.
 Desalination drought proofs
a country by removing
reliance on freshwater
sources.
 Provides fresh water and
prevents water borne
disease to bounce back from
hurricanes, monsoons or
floods.
ENVIRONMENTAL
IMPLICATIONS
"Ocean water is filled with
living creatures, and most of
them are lost in the process of
desalination," says Sylvia Earle,
one of the world's foremost
marine biologists and a
National Geographic Explorerin-Residence. We need to
develop a method that is more
environmentally friendly and
energy efficient.
Impact on Marine Habitants
 Brine released back into ocean
has potential to kill marine life
 Marine habitants get sucked
into desalination plant
equipment
 Release chemicals (used for
pre-treatment and cleaning)
which harms marine life
 Discharged waste has potential
to rise water temperatures,
affecting the habitants
Desalination Plants and Energy Use
 Plants produce large
amounts of
greenhouse gasses due
to high energy needs
 Reverse osmosis uses
about 10 times for
energy than
traditional methods
Use of Land
 Most desalination plants
are located by the sea
shore
 The land is used for
industrial purposes rather
than for recreation and
tourism
CASE STUDY
DESALINATION IMPACTS IN THE SOUTHERN EAST MEDITERRANEAN SEA
Other Environmental Implications
 Rising water temperature
 Discharged waster has
potential to raise water
temperatures of coastal
waters
 It has adverse effect on
marine like and water
quality
 Impact on aquifers
 Danger of seawater or brine
pipes leaking and
penetrating aquifers with
salty water
 Noise
 High-pressure pumps and
energy recovery turbines
produce loud noises
 Noise causes location of
desalination plants to be far
from population centers
Gaza Strip
 Made up of a 40 km coastline
 Very little fertile soil – only 13%
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is arable
Overpopulated with high
growth rates
Poor sewage system which
leads to waste in the
Mediterranean Sea
Many Palestinians fish along
the eastern coast of the
Mediterranean
Coastal zone is very wide
 Has potential as an industrial
zone
 Large continental shelf
Sewage flowing into the sea.
Potential Impact in Gaza Strip
 Severe impact of brine in water coastal water
 Concentration of brine in coastal water could kill marine
life
 Continental shelf will prevent use of deep outfall tunnel
 Unsafe for fishers
 History of pollution and oligotrophoic nature of sea make
the Gaza Strip an unsuitable location for a desalination
plant
Israel Costal Plains
 Israeli Cost of the East Mediterranean
Sea is used extensively for fisheries
and tourism
 Much of the costal plain of Israel is
used for desalination activities rather
than using it for recreation and
tourism
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This has a strong impact
mainly because there is a
limited costal plain, especially in
the north
 More of the costal plain is used
for desalination plants than for
recreation and tourism purposes
 Discharged brine solution could affect
important marine plants particularly
those with important commercial and
medical values
SOCIAL
IMPLICATIONS
 Water is a basic human necessity and
should be available for all citizens.
However, the cost of desalination
comes down to the consumer.
 Most communities cannot afford over
hiked prices for desalted water.
Therefore, desalination contributes
towards social injustice.
 The low income communities are the
ones that will also be affected by the
plants as they will be built in industrial
areas. This would cause air pollution,
noise and traffic in and out of the
plants.
 Ocean desalination can wreck havoc
on marine life and many fish and
other organisms get dragged into the
plant and die. This causes loss of
revenue for the fisherman and is
unethical.
 Desalinated water is not always
perfect and the process itself is not
mastered. The water could become
acidic to the pipes and to the digestive
system.
 A lot of the water that exist the plant
is waste and not drinking water
therefore, it can be said that
desalination is not very efficient.
 According to EPA, these intake structures
kill at least 3.4 billion fish and other organisms annually.
Larger organisms are trapped against the intake screens,and
smaller ones, such as fish eggs and larvae, are drawn through
the intake screens and destroyed in the cooling system.
 As a result, fishermen lose at least 165 million pounds
of fish today and 717.1 million pounds of potential future
catch. This is equivalent to a $212.5 million economic lossto
anglers and commercial fishermen.
Political
Implications
What does desalination mean
for the governments and
peoples of the world?
The Water Problem
 Lead to greater regulation
of the world’s water
 Countries drain and
pollute from common
ocean basin
 Who has the right to
ocean water and how
much can be taken?
 How can countries be held
responsible for pollution?
The Water Problem
 Coastal territory of greater
importance
 Means of revenue as well
as drinking water for
people
 Water trade business
becomes more prevalent
as countries and
corporations take
possession of water
 War on water is a concern
Conclusion
 Desalination is provides the
world with fresh water
 Current methods of
desalination are expensive and
leave an environmental
footprint
 There is room for improvement
To help create a better
understanding of desalination,
we have posted this
presentation on
http://www.scribd.com/doc/4657
2586/Desalination#about
CHECK IT OUT!
Bibliography
 Canadian Nuclear Association. Desalination [homepage on the Internet]. Ottawa (ON):
Canadian Nuclear Association; 2010. [cited 2010 Dec. 24]. Available from:
http://www.cna.ca/curriculum/cna_nuc_tech/desalinationeng.asp?bc=Desalination&pid=Desalination
 Desalination Fact Sheet [home page on the Internet]. Sydney, Australia: n.d. [cited 2010 Dec.
27]. Available from: http://www.ffc.org.au/FFC_files/desal/Whatisdesal inati on-factsheet1.pdf
 Electronics. (n.d.). Desalination. Water & Process Technologies: Water, wastewater and
process systems solutions. Retrieved January 7, 2011, from
http://www.gewater.com/what_we_do/water_scarcity/desalination.jsp
 General Electric. Desalination [homepage on the Internet]. Fairfield (CT): General Electric; n.d.
[cited 2010 Dec. 24]. Available from:
http://www.gewater.com/what_we_do/water_scarcity/desalination.jsp.
 National Research Council. Desalination: A National Perspective. Washington (DC): The
National Academies Press; 2008. 312 p.
 Pereira G. Desalination - A Sustainable Water Supply for the Future [home page on the
Internet]. 2011 Jan. 9. [Desalination - A Sustainable Water Supply for the Future; cited 2011
Jan. 9]. 1 p. Available from: http://www.caribbeanconstruction.com/index.php?option=....
 Qutob M A. Environmental Impacts of Water Desalination Along the Coastal Region of Israel
and the Palestinian Authority [home page on the Internet]. n.d. [cited 2010 Dec. 10]. Available
from: http://www.ipcri.org/watconf/papers/mutaz.pdf