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Whats in My Water Summary:

Desalination in Israel

Water, possibly the most important natural resource on earth, has ensured the well-beingand growth of human civilization. However as humanity progressed over the centuries, our

dependence on and usage of water has increased to the point that water is no longer the

abundant resource it used to be. The country of Israel is one of the nations that have been

badly affected by this. The nation has suffered from water shortages for several years now

and has struggled to supply enough water in order just to meet the water requirements for

households and agriculture. Rapid population growth since the 1940s and the higher

standard of living have contributed to the increase in the demand for water. [3]

In order to tackle this crisis, the Israeli government has turned to desalination of ocean

water. They began to construct plants to desalinate salt water from the ocean using a

process known as reverse osmosis to purify the water. [2] While Osmosis, a natural effect,

which balances the solute concentrations of a solution, Reverse osmosis separates the

solutes from the solvents. [6] Reverse Osmosis is the process of applying pressure to a

contaminated and highly concentrated liquid, force it to pass through a series of

membranes in which all solutes are filtered out. The process requires special filters with the

membranes in order to filter out and separate solutes from the solvents. In theory if this

method was used on salt-water, the process would filter out the salt leaving only clean

drinkable water. However the external pressure applied must be higher than osmoticpressure of the solution in order to prevent the natural osmosis effect from taking place. [4]

The process is quite energy efficient as it consumes about 2 kilowatts of energy per hour

(kWh) to create a single cubic meter (m3) as opposed to 20 years ago when 10kWh were

required to do the same task. [1] Reverse osmosis is very effective at filtering out organic

compounds and bacteria due to the fact that the semi-permeable membranes, that are used

to separate the solutes from the solvents, contain very small pores that restrict bacteria and

similar pathogens that cause illness or disease. This is particularly effective for water that

has been contaminated with water-borne diseases. Unlike other processes such as multi-

stage flash distillation a process in which water is converted to steam to separate the

solvents such as salt and brine, reverse osmosis does not require a heated energy source

which increases overall energy consumption. [5]

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However reverse osmosis is not great for drinking water. The pores in the membranes

restrict minerals that naturally exist in water such as calcium and potassium that are healthy

to the human body. The removal of these minerals could actually cause the water to

become unhealthy for drinking. Another problem with the process is that the membranes

cannot block particles with a smaller molecular structure than water, some of which can be

harmful such as chlorine and pesticides. This often requires a carbon filter as a safety

precaution to filter those chemicals that are able to pass through the membrane. Reverse

osmosis is also a very slow process compared to Multi-stage flash distillation. Reverse

osmosis also wastes about 3 gallons of water per gallon of purified water that is produced

making it a more wasteful process than distillation. [5]

Although more energy efficient than before the desalination plants still require a massive

amount of energy to operate which comes from non-renewable fossil fuels. The burning of

these fossil fuels to generate energy for the desalination plants increases the amount ofgreenhouse gas emissions, contributing to environmental problems such as air pollution.

Chemicals and more concentrated waste from the purification process in reverse osmosis

such as chlorine are released into the ocean. This causes water pollution and endangers the

marine life as the chlorine often forms similar by-products which can cause diseases such as

cancer among animals. [5]

Despite its environmental issues the desalination projects received positive feedback from

the people of Israel. Local support of these projects has increased and people have begun to

back the government into building even more desalination plants. While local support

increased, bordering country Palestine criticized Israel claiming that they have wasted

energy and resources on the projects and have done little but pollute more water.

Palestinian protesters in Qalqiya, Palestine accused Israel of diverting water away from

Palestinian territories claiming that the desalination projects were nothing but an excuse to

hide their stolen that they fill up their swimming pools with and hose off their lawns

while many of us barely have water for basic sanitation an unnamed man who was part

of the protester group in Qalqiya. [7]

In conclusion, desalination, while heavily supported by locals, is not the perfect answer to

Israels water problems. The energy requirements and environmental impact overshadow

the benefits of the purified water. Perhaps in the future a more time-efficient and

environmentally friendly method of desalination will be discovered. However until that time

comes desalination should not be considered a permanent solution to Israels water crisis.

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Bibliography

1. "Ashkelon, Israel."Water Technology. Net Resources International. Web. 08 Feb.2012. .

2. Barkat,Amiram. "Mekorot WinsBattletoBuildAshdod Desalination Plant-Globes."Globes - Israel's Business Area. 22 Feb. 2011. Web. 08 Feb. 2012.

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3. "Israel's Chronic Water Problem."Jewish Virtual Library. Web. 15 Feb. 2012..

4. Kershner,Kate. "HowStuffWorks"Reverse Osmosis: LotsMoreInformation""HowStuffWorks "Science"Spring 2011. Web. 15 Feb. 2012.

.

5. "Reverse Osmosis- Prosand Cons."The History of Water Filters. Web. 15 Feb. 2012..

6. "Reverse Osmosis."Wikipedia, the Free Encyclopedia. Web. 08 Feb. 2012..

7. Wood, Paul. "BBC News | MIDDLE EAST | Israel FacesWater Crisis."BBC News -Home. BritishBroadcasting Corporation, 23 May 2001. Web. 08 Feb. 2012.

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