W O R L D W A T E R S C A R C I T Y: C O N S E R VA T I O N A N D
DESALINATION !
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GIOIETTA KUO!
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FEB 2016!
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WATER STRESS!
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Apart from the global overpopulation problem, water scarcity is as
announced by the World Economic Forum in January 2015 : “The water
crisis is the number one global risk based on impact to society as a
measure of devastation”. The UN defines water stress when an area’s
annual water supplies drop below 1700 cubic meters per person. When it
is below 1000 cubic meters it has water scarcity. It is estimated that 10% of
the world’s population does not have access to safe drinking water. This
will increase as the world’s population is fast growing. The global demand
for fresh water is rising by 640 billion cubic meters a year. A UNESCO
report said that the world’s shortage of freshwater will rise to 2000 billion
cubic meter by 2025. UN warns that if we continue our current trajectory,
we will only have 60% of the water we need in 2030.!
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Where is this water going to come from? The worse hit areas are in
the semi arid areas of Asia, Middle East and North Africa. An IAEA study
showed that 2.3 billion people ( 1/3 of world’s population) live in water
stressed areas, and 1.7 billion of them have less than 1000 cubic meter of
drinking water per year. By 2025 this number could rise to 3.5 billion.!
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Such water scarcity is extremely worrying as it has great effect on the
sustainability of the economic development of our world. As water is
indispensable in all industries - agriculture, mining, energy production, etc
as well as in human well being.!
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To put a human face on these statistics. One cubic meter is 1000
liters. A person everyday drinks about 4 liters. But for agriculture to
produce the food we eat, a person needs 2000 liters a day. So water
scarcity of 1000 cubic meters translates to 2740 liters/day person. On the
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whole 70% of this goes to agriculture, More than 20% for industry and this
does not leave much for personal use. !
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The fundamental reason of water scarcity in China is the fact that
though China has 21% of the world’s population, it has only 7% of the
world’s freshwater supplies. While 80% of rainfall and snow melt
occurs in the South, only 20% of moisture occur in the mostly desert
regions of the North. North China is particularly dry. The average
annual rainfall of Beijing, for example, is only 57 cm per year. ( 4.8 cm
per month) Therefore the The South-North Water Transfer Project is
bringing water from the Yangtze river, whose water come from ice melt
of the Himalayas, to the North. Demand is fast outstripping supply as
already the consumption levels are 70% higher than in 2012. It is
projected that by 2020 water demand will reach 670 billion cubic
meters a year while the resources are dwindling with time.!
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According to state media reports, before the arrival of infusions
from the South-North Water Diversion Project Beijing’s annual percapita water volume was just 100 cubic meters, 1.25% of the world’s
average level. With the water from the south, that figure will go up to
150 cubic meters per person ( 411 liters/day). The average personal
residential use of water is 86 liters/day compared to UK with 150 and
US 560 liters/day.!
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Air pollution in China is a well known problem. While this results
in acid rain, not many are aware that water scarcity and water
pollution pose a greater threat to china’s thirst wellbeing, as well as for
food security, energy use, urbanization, modernization and overall
economic development.!
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However, adding to water scarcity is the nation wide water
pollution problem. The Chinese government reported that nearly 60
percent of China’s groundwater is polluted. with 35% of water so low
quality that it is not fit for industry, agriculture or human
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consumption. Yet it is used. There are reports that 10% of the
rice produced is contaminated with cadmium. !
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CONSERVATION !
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We should concentrate on more efficient use of existing
resources:!
* Better water sustainable management. !
* Pollution control.!
* Water reclamation.!
* Reducing leakage of agriculture irrigation.!
* Collection of rainwater on rooftops and streets.!
* Recyling of urban residential waste. This is an imperative for the
future. Many countries are experimenting with this problem, The top 5
wastewater treatment plants are:!
-USA. Stickney Metropolitan Water Reclamation District of Greater Chicago produces 5.45 million cubic meters/day, serving !
2.4 million people. With an annual budget of $450 million, !
it comes to $0.22/cubic meters. This is about 1/2 to!
1/3 of the cost of desalination ( see section on Desalination) !
-USA Boston 4.8 million cubic meters/day!
-USA Detroit 3.48 million cubic meters/day!
-China. Shanghai 2.0 million cubic meters/day!
-Mexico. Atotonilco plant 2.0 million cubic meters/day.!
* Increase the price of water. This has negative effects such as !
driving away local industrial developments.!
* Upgrading storm water systems.
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DESALINATION
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As world’s glaciers are melting fast, the drying of aquifers
through overpumping and pollution of rivers, the world does not have
many options left.!
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DESALINATION TECHNOLOGY
there are basically 2 principles
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*Reverse Osmosis - RO
Sea water is forced across a semi-permeable membrane by
applying high pressure with electric pumps.
The water diffuses
through the membrane while the salts are left behind. This process is
electricity intensive, around 3-8 kWh/cubic meter ( = one ton) of water
produced. This accounts for 60% of the world’s capacity in 2011!
Pumping seawater to pressures of more than 70 kg/ per square cm
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takes less energy than boiling it—but it is still expensive.
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There are new technologies coming on line which are more
efficient than standard RO and hence reduce energy cost: !
1) Use of nanotechnoloy in the form of graphene membrane will save
cost and produce greater efficiency. !
2) Use of nanotubes through the membrane. An electric charge at the
nanotube mouth repels positively charged salt ions. The uncharged
water molecules slip through with little friction, reducing pumping
pressure!
3) Water molecules pass through channels made of aquaponne
proteins that efficiently conduct water in and out of living cells. A
positive charge will repel salt molecules near each channels center.
Repelling salt. !
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* Multi-Flash Distillation (MFD) and Multi-Effect distillation(MED) !
It is a brute force method needing much energy. This is a simple
distillation process where sea water is heated and distilled.
It is
capable of using waste heat from power plants. This process
requires 10 kWh/cubic meter. !
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Desalination is a great solution for the residential drinking
usage problem. But is now becoming widely used for agriculture and
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industrial uses. However it is energy, mostly electricity, intensive
and is therefore an expensive business Both in the capital cost and in
the running cost. It is about two to three times as expensive as
treating rainwater and waste water.!
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It energy costs are around 3-10 kWh per cubic meter. But
that depends on some variables such as distance transferred of sea
water and distance traveled to pump fresh water to the cities. In
Israel, for example, 3.5 kWh is needed for electricity of desalination
- 1.3 kWh to pump seawater to the plant and 2.2 kWh for the RO
desalination process. At the present price of electricity at $0.12/
kWh, 3.5 kWh comes to $0.42 /cubic meters. This ia about twice
the cost of waste treatment plants.
For Multi FlashDistillation
systems the cost is even more.
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According to International Desalination Association ( IDA),
which is world’s most reputable authority on desalination. We get
the following figures: By 2013 there are are altogether more than
17,000 desalination plants in the world. The global capacity
commissioned as of 2013 is more than 80 million cubic meters per
day. So far, water produced is more than 66.5 million cubic meters
per day. Most of this goes to industry such as agriculture, electricity
generation power plants, refining, oil and gas, mining for coal and
metals etc. There are more than 300 million people who rely on
desalination for whole or part of their daily use.
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The break down by country is :
Country - Commissioned seawater desalination capacity (m³/d) Saudi Arabia - 9,170,391 UAE - 8,381,299 Spain - 3,781,314 5
Kuwait - 2,586,761 Algeria - 2,364,055 Australia - 1,823,154 Qatar - 1,780,708 Israel - 1,532,723 China - 1,494,198 Libya - 1,048,424
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Total = 30 million cubic meters/day
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However, if we look at only the largest plants, the figure are roughly half
that given by IDA. Of course, the difference comes from small units
scattered in the countries.
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WORLD’S LARGE NEW DESALINATION PROJECTS!
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Desalination plants operate in more than 120 countries in the
world, including Saudi Arabia, Oman, United Arab Emirates, Spain,
Cyprus, Malta, Gibraltar, Cape Verde, Portugal, Greece, Italy, India,
China, Japan, and Australia.
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Many are just coming on line. The largest are the following:!
* SAUDI ARABIA !
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In Ras Al Khair. it uses a hybrid of RO and MSF technology with a
gigantic capacity of 1.025 million cubic meters per day. The construction
cost was also a huge $7.2 billion.!
Yet another plant is in plan in Rabigh by the Red sea that will have a
capacity to make 0.6 million cubic meters. !
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*UNITED ARAB EMIRATES, UAE!
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Capacity 4.6 million cubic meters/day. Construction cost $2.7 billion.
It is actively pursuing the use of solar energy.!
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*AUSTRALIA!
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With its long standing drought, it generates combined 1.45 million
cubic meters/day with 6 plants using RO technology and some renewable
energy from wind. In total, allowing for small plants, the capacity is around
2.2 million cubic meters/day!
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* SPAIN!
It has 40 years of history in desalination and is actively selling its
expertise around the world. It has 900 small desalination plants producing a
total of 1.5 million cubic meters/day. In project is a plan to produce 1.7
million cubic meters/day, using where possible renewable energy!
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* CHINA
Currently production is 0.75 million cubic meters/day. It is
building a 3 million cubic meters/day RO plant to supply Beijing by
2020. The construction plant will cost $1.1 billion . But the pipeline to
Beijing will cost an additional $1.6 billion.!
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* ISRAEL!
Sorek was built in 2013 with a output capacity of 0.627 million cubic
meters per day. By 2016, some 50 percent of the country’s water is
expected to come from desalination.
It uses highly efficient much
improved RO membranes so it saves energy.
Construction cost: $400
million.!
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* ALGERIA!
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Has a large desalination plant using RO producing 0.5 million cubic
meters/day.!
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* USA!
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In Carlsbad, San Diego, California To open in 2016 using RO. Will
produce 0.19 million cubic meters per day at a capital cost of $ 1 billion.!
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DESALINATION IN CHINA!
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In China, about 400 cities face serious water shortage
problems. It has 112 seawater desalination plants in 2014, which
could produce 0.93 million cubic meters/day, according to the State
Oceanic Administration. The government aims to quadruple its
seawater desalination capacity to 3.6 million cubic meters/day by
2020. !
Key industrial sectors such as thermal/nuclear power plants, steel
and metal production plants, or centralized industrial parks take up more
than 90% of the overall desalinated water in China
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A 100,000 cubic meter/day seawater RO plant supplied by
Abengoa of Spain started operating early in 2013 at Qingdao in
Shandong province. Another project is for a 330,000 cubic meter/day
plant near Daya Bay.
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A 50,000 cubic meter/day Aqualyng plant was completed in
October 2011 at Caofeidian on Bohai Bay in Hebei province, and a
second stage doubled this in 2012. The Hong Kong based Beijing
Enterprises Water Group (BEWG) with Aqualyng is building a 1 million
cubic meter/day RO plant at Caofeidian for RMB 7 billion($ 1.06
billion) to supply Beijing through a 270 km pipeline by 2019, providing
water for 1/3 of its residents. A 3 million cubic meter/day plant is
planned to expand this to supply the capital. The pipeline, itself a major
part of the project, will cost about RMB 10 billion($ 1.5 billion), and
supply desalinated water at RMB 8 ($ 1.22) /cubic meter.
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In March 2013 the National Development and Reform Commission
announced new plans for seawater desalination, including for the cities of
Shenzhen and Zhoushan, Luxixiang Island in Zhejiang Province, Binhai New
Area in Tianjin, Bohai New Area in Hebei, and several industrial parks and
companies. The cost is likely to be some RMB 21 billion ($3.2 billion).
China aims to produce 2.2 million cubic meter/day of desalinated water by
2015, more than three times the 2011 level. More than half of the freshwater
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is channelled to islands and more than 15% of water delivered to coastal
factories will come from the sea by 2015, according to the plan. This plan
will have an investment cost around $21 billion RMB ( $3.35 billion). !
A 300,000 cubic meter/day seawater desalination plant at Tianjin is
under construction and will be the first zero-liquid discharge (ZLD) plant in
the world. The freshwater is due to supply petrochemical plants from 2017.
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NUCLEAR DESALINATION!
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We point out here a fast growing resource - nuclear desalinationwhich has high potentials that will last throughout the 21st century.
Its
advantage is it does not emit Green House Gases GHG. And its price is
very competitive with water generated from other fuels - especially coal.!
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The affordability question all boils down to the cost of energy.
Since coal power stations produce too much GHG and are out of
favor. China is turning to nuclear power stations and there is much
research on the project of building 50 thorium molten salt reactors
which are safer and economical than standard plutonium reactors.!
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Large-scale deployment of nuclear desalination on a commercial
basis will depend primarily on economic factors. Indicative costs are
US$ 70-90 cents per cubic meter, much the same as fossil fuel plants
in the same areas.!
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China is looking at the feasibility of a nuclear seawater
desalination plant in the Yantai area of Shandong Peninsula, producing
80,000-160,000 cubic meter/day by MED ( Multi-Effect Distillation)
process, using a 200 MWt NHR-200 reactor.
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COMPARISON OF DESALINATION COSTS FOR DIFFERENT
FUELS!
Following are just some typical values.
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A
B
C
D
E
F!
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coal
$4 billion 400,000
$3 (RO)
0
6 million tons!
$22(MFD)!
natural gas $3 billion 400,000
$7.30
0
3 million tons!
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Wind
$6 billion
45,000
$12.50
0
carbon credit!
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nuclear
$3 billion
400,000 $0.5-1.0 (RO) 700 MWe carbon credit !
$1.5 (MED)!
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A= Nature of plant. Capacity 1100 MWe!
B= Approximate cost of plant!
C= Water produced in cubic meters/day!
D= Water price / cubic meters including cost of fuel!
E= Additional energy output!
F= Yearly GHG emission!
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As can be seen from the table.
nuclear desalination is very price
competitive as well as having advantages of not using fossil fuel. !
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COGENERATION !
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For cogeneration we can use power stations fueled by thermal
power plants or nuclear reactors !
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Lack of freshwater along the many coastal cities of China makes it
very suitable for the installation of small and medium sized reactors for
cogeneration. The hot water from the final cooling system is used to drive
turbines for electricity generation.
The low pressure steam from the
turbines is then used for desalination. The beauty of the cogeneration
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setup is when the grid is busy, reactor is used for generating electricity.
When the grid demand is low at night, it switches to desalination. so there
is no waste energy !
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An IAEA preliminary feasibility study on nuclear desalination in
Algeria was published in 2015 for Skikda on the Mediterranean coast, using
cogeneration. The nuclear energy option was very competitive compared with
fossil fuels.
WORLD COGENERATION EXPERIENCE WITH NUCLEAR POWER!
The feasibility of integrated cogeneration nuclear desalination plants
has been proven with over 150 reactor-years of experience, chiefly in
Kazakhstan, India and Japan. *Kazakhstan The BN-350 fast reactor at Aktau, successfully supplied up to 135
MWe of electric power while producing 80,000 cubic meter/day of potable
water over some 27 years, about 60% of its power being used for heat and
desalination. It established the feasibility and reliability of such cogeneration
plants. (In fact, oil/gas boilers were used in conjunction with it, and total
desalination capacity through ten MED units was 120,000 cubic meters/day.)
*Japan
some 10 desalination facilities linked to pressurized water reactors
operating for electricity production yield some 14,000 cubic meter/day of
potable water, and over 100 reactor-years of experience have accrued. !
*India It has been engaged in desalination research since the 1970s. In 2002 a
demonstration plant coupled to twin 170 MWe nuclear power reactors
(PHWR) was set up at the Madras Atomic Power Station, Kalpakkam. This
hybrid Nuclear Desalination Demonstration Project (NDDP) comprises a
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reverse osmosis (RO) unit with 1800 cubic meters/day capacity and a multistage flash (MSF) plant unit of 4500 cubic meter/day costing about 25%
more. This is the largest nuclear desalination plant based on hybrid MSF-RO
technology using low-pressure steam and seawater from a nuclear power
station. They incur a 4 MWe loss in power from the plant.
A low temperature (LTE) nuclear desalination plant uses waste heat
from the nuclear research reactor at Trombay has operated since about 2004
to supply make-up water in the reactor.
*Pakistan
In 2010 commissioned a 4800 cubic meter/day MED desalination plant,
coupled to the Karachi Nuclear Power Plant (KANUPP, a 125 MWe PHWR)
though in 2014. It has been operating a 454 cubic meter/day RO plant for its
own cooling.
*China General Nuclear Power (CGN) has commissioned a 10,080 cubic
meter/day seawater desalination plant using waste heat to desalinate and
provide cooling water at its new Hongyanhe project at Dalian in the northeast
Liaoning province.
* Much relevant experience comes from nuclear plants in Russia, Eastern
Europe and Canada where district heating is a by-product.
CONCLUSION
As the global population is fast growing, water scarcity is becoming more
and more acute. How will 9 billion people in 2050 manage with so little
water which is already present with us today? Conservation, in particular
recycling of urban waste water is imperative. Desalination is expensive and
energy intensive. But more countries are now building large desalination
plants not just for drinking water but for irrigation in agriculture and for
industrial uses like mining for coal which is water intensive. In China,
pollution control is number one priority. Both in air pollution leading to acid
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rain, and pollution in the water system - dumping of waste in rivers for
example. Nuclear cogeneration of fresh water using improved new RO
technique is for our future. However, we must not forget that the world’s
energy resources are NOT limitless.
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Gioietta Kuo, from Cambridge, Oxford and Princeton, is a research
physicist specializing in energy problems. She has published over 100
articles in World Future Society, wfs.org, amcips.org and other worldwide
think tanks. As well as in ‘ People’s Daily’ and ‘World Environment’ ,
Magazine of the Chinese Ministry of Environmental
Protection, and
others in China. She can be reached at <[email protected].>
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