What is the Desalination Process?

New Haven, CT — Yale researchers are building a pilot-scale plant to demonstrate a novel forward osmosis desalination process. The project, led by Professor Menachem Elimelech and graduate students Robert L. McGinnis and Jeffery R. McCutcheon, will feature a process that differs from existing desalination technologies in that it uses osmotic pressure, rather than hydraulic pressure or thermal evaporation, to separate fresh water from a seawater or brackish water source. This approach promises significant reductions in energy consumption and cost, as well as high feed-water recoveries and greatly reduced brine discharge streams.

Markets and Stats:


It is estimated that some 30% of the world’s irrigated areas suffers from salinity problems and remediation is seen to be very costly.

  • In 2002 there were about 12,500 desalination plants around the world in 120 countries. They produce some 14 million m3/day of freshwater, which is less than 1% of total world consumption.
  • The most important users of desalinated water are in the Middle East, (mainly Saudi Arabia, Kuwait, the United Arab Emirates, Qatar and Bahrain), which uses about 70% of worldwide capacity; and in North Africa (mainly Libya and Algeria), which uses about 6% of worldwide capacity.
  • Among industrialized countries, the United States is one of the most important users of desalinated water (6.5%), especially in California and parts of Florida.



Most desalination today uses fossil fuels, contributing to increased levels of greenhouse gases. Total world capacity is approaching 40 million m³/day of potable water, at some 15,000 plants. Most of these are located in the Middle East and North Africa, and use distillation processes. The largest plant produces 454,000 m³/day.

There are several technologies being used in the world today for desalination: reverse osmosis (RO) and multi-stage flash distillation (MSF). A minority of plants use other technologies, such as multi-effect distillation (MED) or vapour compression (VC). All of the processes are energy intensive requiring anywhere from five to 200 kWh per cubic metre of water.

Some 10% of Israel’s water is desalinated, and one large RO plant provides water at a cost of 50 cents per cubic metre. Malta gets two-thirds of its potable water from RO. In 2005, Singapore commissioned a large RO plant supplying 136,000 m³/day — 10% of its needs, at a cost of 49 cents US per cubic metre. All three plants use fossil fuels to desalinate the water.

Here are our parameters for saline water:

  • Fresh water – Less than 1,000 ppm
  • Slightly saline water – From 1,000 ppm to 3,000 ppm
  • Moderately saline water – From 3,000 ppm to 10,000 ppm
  • Highly saline water – From 10,000 ppm to 35,000 ppm

By the way, ocean water contains about 35,000 ppm of salt.

Source: Saline-water resources of North Dakota, USGS Water Supply Paper 1428, 1958.

Membrane processes: A more recent development, and now more widely used, relies on what is called a semi-permeable membrane to separate salt from water. Simply put, a synthetic membrane is made, with pores so tiny that water molecules can pass through it, but other molecules, especially salts, cannot.

  • The Middle East is still the largest user of desalination and seawater desalination plants of capacity over 300 ML/d are being constructed there (e.g. Ashkelon plant in Israel). There is increasing use in Europe in countries such as Spain and in North America with plants of over 100ML/d capacity in the Caribbean.


Other Sources of Information

International Desalination Association (IDA) http://www.idadesal.org – Journal – The International Desalination and Water Reuse Quarterly
Australasian Desalination Association (ADA) – http://www.ceic.unsw.edu.au/ada/ – publishes regular newsletters for members.
European Desalination Society (EDS) http://www.edsoc.com

1. Saudi Arabia 10,759,693 m3/d 17%
2. UAE 8,428,456 m3/d 13%
3. USA 8,133,415 m3/d 13%
4. Spain 5,249,536 m3/d 8%
5. Kuwait 2,876,625 m3/d 5%
6. Algeria 2,675,958 m3/d 4%
7. China 2,259,741 m3/d 4%
8. Qatar 1,712,886m3/d 3%
9. Japan 1,493,158 m3/d 2%
10. Australia 1,184,812m3/d 2%


The global market for desalination currently stands at about US $35 billion annually and could double over the next 15 years.

Among industrialized countries, the United States is one of the most important users of desalinated water (6.5%), especially in California and parts of Florida.

http://www.emwis.net/topics/Desalination/facts-and-figures-about-water-and  Unesco Water report 2008

With the growth of membrane science, reverse osmosis (RO) overtook MSF as the leading desalination technology, and should be considered the baseline technology. Presently, RO of seawater can be accomplished with an energy expenditure in the range of 11-60 kJ/kg at a cost of $2 to $4 per 1000 gallons. The theoretical minimum energy expenditure is 3-7 kJ/kg.


The potential for desalination plants is huge–in 2005, Harvard Business School estimated that the water industry does $400 billion in business each year (including sales and investment). By 2025, the United States will need about $500 billion in upgrades to its water system infrastructure–desalination plants could capture much of this spending.


Considering that almost one quarter of the world’s population lives

less than 25 km from the coast, seawater could become one of the main sources of freshwater in the

near future.

http://ec.europa.eu/environment/etap/inaction/pdfs/watedesalination.pdf – 2006

The largest market will continue to be the Gulf area, where the combination of rapidly growing populations, depleted ground water resources and the retirement of capacity built during the oil boom years of the 1970s and early 1980s will require a near doubling of the total capacity. Growth in the region would be stronger but for concerns about Saudi Arabia’s ability to finance its required capacity within the timeframe.

- The largest growth market will be the Mediterranean Rim, where Algeria, Libya, and Israel are anticipating capacity increases in excess of 300%. With desalination back on the political agenda in Spain, the total increase in capacity in the Mediterranean region will be 179%.

- The US market will make the break-through into large scale municipal desalination (it is currently predominantly a brackish water desalinator). Already it has nearly 2 million cubic meters of seawater desalination on the drawing board, although financing issues and the permitting process will delay the growth of the market.

- China and India are also set to enter the large-scale seawater desalination market. Both have large populations in water stressed regions, and political backing for higher water tariffs. The 650,000m3/d additional capacity these two countries are expected to bring on line by 2015 could be the start of a massive move into desalination in the longer run.


Publicly traded companies involved in the desalination sector include Veolia Environnement, Suez Environnement, General Electric and Energy Recovery Inc. They enjoy strong long term prospects in this market, although revenues in the current year will have been impacted.

Desal companies profits have been downgraded 2010 and 2011 due to

  • The completion of major desalination plant building programmes in Algeria, Spain, and Australia.
  • The weakness of the real estate market in the UAE, Southern Spain and the Western United States
  • Project delays and postponements related to a variety of unconnected issues such as elections, financing difficulties, heavy rains, and administrative issues.


Recent statistics show that global water consumption has been twice that of population growth, and meeting this demand has become a key environmental and economic impediment facing many countries.


It is estimated that some 30% of the world’s irrigated areas suffers from salinity problems and remediation is seen to be very costly.


Fresh Water Stress


Global Water Footprint

Via Waterfootprint.org. Dark red countries have the worst footprints – between 2.1 and 2.5 million liters of water per capita each year.

The top five biggest average daily users of water are the U.S., Australia, Italy, Japan, and Mexico – all five of these use well over 300 liters daily. The countries where water poverty is the worst and water usage is the lowest are Mozambique, Rwanda, Haiti, Ethiopia, and Uganda – these five use 15 liters or less daily.


Freshwater withdrawals have tripled over the last 50 years. Demand for freshwater is increasing by 64 billion cubic meters a year (1 cubic meter = 1,000 liters)

  • The world’s population is growing by roughly 80 million people each year.
  • Changes in lifestyles and eating habits in recent years are requiring more water consumption per capita.
  • The production of biofuels has also increased sharply in recent years, with significant impact on water demand. Between 1,000 and 4,000 litres of water are needed to produce a single litre of biofuel.
  • Energy demand is also accelerating, with corresponding implications for water demand.

Almost 80% of diseases in so called “developing” countries are associated with water, causing some three million early deaths. For example, 5,000 children die every day from diarrhoea, or one every 17 seconds.


http://www.worldometers.info/water/  -   Real time water usage this year in the billions of litres.

A report by Lux Research indicates that to meet the demands of a growing human population, worldwide desalinated water supply must triple by 2020. This report indicates that desalination is feasible, as the global water desalination market is expected to expand at a compound annual growth rate of 9.5 percent over the next 10 years.


World Water Chart – Who has it and who doesn’t


Desalination Competitors

Elsevier – magazine

Saltworks Technologies Inc – Vancouver, BC

Pure-Aqua –

Veolia – supplies Sydney water Desal plant

Parker Racor – division of Parker Hanafin, they produce 160 – 100,000 GPD machines for seaside properties, boats, luxury yachts, military, submarines etc  http://www.villagemarine.com/about_ph.html