Water softening
Water softening is the act of reducing the dissolved calcium, magnesium, and to some degree manganese and ferrous iron ion concentration in hard water. A common water softener is sodium carbonate (Na2CO3).These "hardness ions" cause three major kinds of undesired effects. Most visibly, metal ions react with soaps and calcium-sensitive detergents, hindering their ability to lather and forming a precipitate—the familiar "bathtub ring". Presence of "hardness ions" also inhibits the cleaning effect of detergent formulations.
Second, calcium and magnesium carbonates tend to precipitate out as hard deposits to the surfaces of pipes and heat exchanger surfaces. This is principally caused by thermal decomposition of bi-carbonate ions but also happens to some extent even in the absence of such ions. The resulting build-up of scale can restrict water flow in pipes. In boilers, the deposits act as an insulation that impairs the flow of heat into water, reducing the heating efficiency and allowing the metal boiler components to overheat. In a pressurized system, this can lead to failure of the boiler. The damage caused by calcium carbonate deposits varies depending on the crystalline form, for example, calcite or aragonite.
Third, the presence of ions in an electrolyte, in this case, hard water, can also lead to galvanic corrosion, in which one metal will preferentially corrode when in contact with another type of metal, when both are in contact with an electrolyte. However the sodium (or potassium) ions released during conventional water softening are much more electrolytically active than the calcium or magnesium ions that they replace and galvanic corrosion would be expected to be substantially increased by water softening and not decreased. Similarly if any lead plumbing is in use, softened water is likely to be substantially more plumbo-solvent than hard water
Ion-exchange resin devices
Conventional water-softening appliances intended for household use depend on an ion-exchange resin in which "hardness" ions trade places with sodium ions that are electrostatically bound to the anionic functional groups of the polymeric resin. A class of minerals called zeolites also exhibits ion-exchange properties; these minerals were widely used in earlier water softeners. Water softeners may be desirable when the source of water is a well, whether municipal or private.[3]How it works
The water to be treated passes through a bed of the resin. Negatively-charged resins absorb and bind metal ions, which are positively charged. The resins initially contain univalent hydrogen, sodium or potassium ions, which exchange with divalent calcium and magnesium ions in the water. As the water passes through the resin column, the hardness ions replace the hydrogen, sodium or potassium ions which are released into the water. The "harder" the water, the more hydrogen, sodium or potassium ions are released from the resin and into the water.Resins are also available to remove carbonate, bi-carbonate and sulphate ions which are absorbed and hydroxyl ions released from the resin. Both types of resin may be provided in a single water softener.
Regeneration
As these resins become loaded with undesirable cations and anions they gradually lose their effectiveness and must be regenerated. If a cationic resin is used (to remove calcium and magnesium ions) then regeneration is usually effected by passing a concentrated brine, usually of sodium chloride or potassium chloride, or hydrochloric acid solution through them.For anionic resins a solution of sodium or potassium hydroxide (lye) is used. Most of the salts used for regeneration get flushed out of the system and may be released into the soil or sewer. These processes can be damaging to the environment, especially in arid regions. Some jurisdictions prohibit such release and require users to dispose of the spent brine at an approved site or to use a commercial service company. Most water softener manufacturers provide metered control valves to minimize the frequency of regeneration. It is also possible on most units to adjust the amount of reagent used for each regeneration. Both of these steps are recommended to minimize the impact of water softeners on the environment and conserve on reagent use. Using acid to regenerate lowers the pH of the regeneration waste.
In industrial scale water softening plants, the effluent flow from re-generation process can be very significant. Under certain conditions, such as when the effluent is discharged in admixture with domestic sewage, the calcium and magnesium salts may precipitate out as hardness scale on the inside of the discharge pipe. This can build up to such an extent so as to block the pipe, as happened to a major chlor-alkali plant on the south Wales coast in the 1980s.
If potassium chloride is used, the same exchange process takes place, except that potassium is exchanged for the calcium, magnesium and iron instead of sodium. This is a more expensive option and may be unsuited for people on potassium-restricted diets.
In residential or small commercial softeners. salt bridges and salt cakes can easily occur if no routine maintenance is performed. This could be done by poking a broom handle down the salt tank to break up salt clumps and bridges. Also, every so often, salt should be emptied out of the tank, and the sides of the brine tank should be wiped down with a dilluted vinegar/water solution.
Effects of sodium
For people on a low-sodium diet, the increase in sodium levels (for systems releasing sodium) in the water can be significant, especially when treating very hard water. A paper by Kansas State University gives an example: "A person who drinks two litres (2L) of softened, extremely hard water (assume 30 gpg) will consume about 480 mg more sodium (2L x 30 gpg x 8 mg/L/gpg = 480 mg), than if unsoftened water is consumed." This is a significant amount, as they state: "The American Heart Association (AHA) suggests that the 3 percent of the population who must follow a severe, salt-restricted diet should not consume more than 400 mg of sodium a day. AHA suggests that no more than 10 percent of this sodium intake should come from water. The EPA’s draft guideline of 20 mg/L for water protects people who are most susceptible." Most people who are concerned with the added sodium in the water generally have one tap in the house that bypasses the softener, or have a reverse osmosis unit installed for the drinking water and cooking water, which was designed for desalinisation of sea water. Potassium chloride can also be used instead of sodium chloride, which would have the added benefit of helping to lower blood pressure, though for about 4 times the cost.Chelating agents
Chelators are used in chemical analysis, as water softeners, and are ingredients in many commercial products such as shampoos and food preservatives. Citric acid is used to soften water in soaps and laundry detergents. A commonly used synthetic chelator is EDTA.Physical conditioners
Physical conditioners treat water by subjecting it to a magnetic field or radio waves and claim to provide similar benefits to water softening. These devices are controversial. In the UK, Southern Water's factsheet states "by the modern definition, physical conditioning does not soften water, and any such claim is incorrect. However, physical conditioning can make water seem softer".Ion exchange
Typical ion exchangers are ion exchange resins (functionalized porous or gel polymer), zeolites, montmorillonite, clay, and soil humus. Ion exchangers are either cation exchangers that exchange positively charged ions (cations) or anion exchangers that exchange negatively charged ions (anions). There are also amphoteric exchangers that are able to exchange both cations and anions simultaneously. However, the simultaneous exchange of cations and anions can be more efficiently performed in mixed beds that contain a mixture of anion and cation exchange resins, or passing the treated solution through several different ion exchange materials.
Ion exchangers can be unselective or have binding preferences for certain ions or classes of ions, depending on their chemical structure. This can be dependent on the size of the ions, their charge, or their structure. Typical examples of ions that can bind to ion exchangers are:
- H+ (proton) and OH− (hydroxide)
- Single charged monoatomic ions like Na+, K+, or Cl−
- Double charged monoatomic ions like Ca2+ or Mg2+
- Polyatomic inorganic ions like SO42− or PO43−
- Organic bases, usually molecules containing the amino functional group -NR2H+
- Organic acids, often molecules containing -COO− (carboxylic acid) functional groups
- Biomolecules which can be ionized: amino acids, peptides, proteins, etc.
Applications
Most typical example of application is preparation of high purity water for power engineering, electronic and nuclear industries; i.e. polymeric or mineralic insoluble ion exchangers are widely used for water softening, water purification, water decontamination, etc.
Ion exchange is a method widely used in household (laundry detergents and water filters) to produce soft water. This is accomplished by exchanging calcium Ca2+ and magnesium Mg2+ cations against Na+ or H+ cations.
Industrial and analytical ion exchange chromatography is another area to be mentioned. Ion exchange chromatography is a chromatographical method that is widely used for chemical analysis and separation of ions. For example, in biochemistry it is widely used to separate charged molecules such as proteins. An important area of the application is extraction and purification of biologically produced substances such as proteins (amino acids) and DNA/RNA.
Ion-exchange processes are used to separate and purify metals, including separating uranium from plutonium and other actinides, including thorium, and lanthanum, neodymium, ytterbium, samarium, lutetium, from each other and the other lanthanides. There are two series of rare earth metals, the lanthanides and the actinides, both of which families all have very similar chemical and physical properties. Using methods developed by Frank Spedding in the 1940's, ion-exchange used to be the only practical way to separate them in large quantities, until the advent of solvent extraction techniques which can be scaled up enormously.
A very important case is the PUREX process (plutonium-uranium extraction process) which is used to separate the plutonium and the uranium from the spent fuel products from a nuclear reactor, and to be able to dispose of the waste products. Then, the plutonium and uranium are available for making nuclear-energy materials, such as new reactor fuel and nuclear weapons.
The ion-exchange process is also used to separate other sets of very similar chemical elements, such as zirconium and hafnium, which incidentally is also very important for the nuclear industry. Zirconium is practically transparent to free neutrons, used in building reactors, but hafnium is a very strong absorber of neutrons, used in reactor control rods.
Ion exchangers are used in nuclear reprocessing and the treatment of radioactive waste.
Ion exchange resins in the form of thin membranes are used in chloralkali process, fuel cells and vanadium redox batteries. Ion exchange can also be used to remove hardness from water by exchanging calcium and magnesium ions for hydrogen and chlorine ions in an ion exchange column.
Other applications
- In soil science, cation exchange capacity is the ion exchange capacity of soil for positively charged ions. Soils can be considered as natural weak cation exchangers.
- In planar waveguide manufacturing, ion exchange is used to create the guiding layer of higher index of refraction.
- Dealkalization, removal of alkali ions from a glass surface.
- Chemically strengthened glass, produced by exchanging Na+ for K+ in glass surfaces using KNO3 melts.
Desalination
Water is desalinated in order to convert salt water to fresh water so it is suitable for human consumption or irrigation. Sometimes the process produces table salt as a by-product. It is used on many seagoing ships and submarines. Most of the modern interest in desalination is focused on developing cost-effective ways of providing fresh water for human use in regions where the availability of fresh water is, or is becoming, limited.
Large-scale desalination typically uses extremely large amounts of energy as well as specialized, expensive infrastructure, making it very costly compared to the use of fresh water from rivers or groundwater.
The world's largest desalination plant is the Jebel Ali Desalination Plant (Phase 2) in the United Arab Emirates. It is a dual-purpose facility that uses multi-stage flash distillation and is capable of producing 300 million cubic metres of water per year. By comparison the largest desalination plant in the United States is located in Tampa Bay, Florida and operated by Tampa Bay Water, which began desalinating 25 million gallons (US Gal.) (95000 m³) of water per day in December 2007. The Tampa Bay plant runs at around 12% the output of the Jebel Ali Desalination Plants. A January 17, 2008, article in the Wall Street Journal states, "World-wide, 13,080 desalination plants produce more than 12 billion gallons of water a day, according to the International Desalination Association."
A - Steam in
B - Seawater in
C - Potable water out
D - Waste out
E - Steam out
F - Heat exchange
G - Condensation collection
H - Brine heater
Methods
The traditional process used in these operations is vacuum distillation—essentially the boiling of water at less than atmospheric pressure and thus a much lower temperature than normal. This is because the boiling of a liquid occurs when the vapor pressure equals the ambient pressure and vapor pressure increases with temperature. Thus, because of the reduced temperature, energy is saved. A leading distillation method is multi-stage flash distillation accounting for 85% of production worldwide in 2004.
Considerations and criticism
Cogeneration
Cogeneration is the process of using excess heat from power production to accomplish another task. In the sense of desalination, cogeneration is the production of potable water from seawater or brackish groundwater in an integrated, or "dual-purpose", facility in which a power plant is used as the source of energy for the desalination process. The facility’s energy production may be dedicated entirely to the production of potable water (a stand-alone facility), or excess energy may be produced and incorporated into the energy grid (a true cogeneration facility). There are various forms of cogeneration, and theoretically any form of energy production could be used. However, the majority of current and planned cogeneration desalination plants use either fossil fuels or nuclear power as their source of energy. Most plants are located in the Middle East or North Africa, due to their petroleum resources and subsidies. The advantage of dual-purpose facilities is that they can be more efficient in energy consumption, thus making desalination a more viable option for drinking water in areas of scarce water resources.
Additionally, the current trend in dual-purpose facilities is hybrid configurations, in which the permeate from an RO desalination component is mixed with distillate from thermal desalination. Basically, two or more desalination processes are combined along with power production. Such facilities have already been implemented in Saudi Arabia at Jeddah and Yanbu.
A typical aircraft carrier in the U.S. military uses nuclear power to desalinate 400,000 gallons (US Gal.) or 1514 m³ of water per day.
Economics
A number of factors determine the capital and operating costs for desalination: capacity and type of facility, location, feed water, labor, energy, financing and concentrate disposal. Desalination stills now control pressure, temperature and brine concentrations to optimize the water extraction efficiency. Nuclear-powered desalination might be economical on a large scale.While noting that costs are falling, and generally positive about the technology for affluent areas that are proximate to oceans, one study argues that "Desalinated water may be a solution for some water-stress regions, but not for places that are poor, deep in the interior of a continent, or at high elevation. Unfortunately, that includes some of the places with biggest water problems." and "Indeed, one needs to lift the water by 2000 m, or transport it over more than 1600 km to get transport costs equal to the desalination costs. Thus, it may be more economical to transport fresh water from somewhere else than to desalinate it. In places far from the sea, like New Delhi, or in high places, like Mexico City, high transport costs would add to the high desalination costs. Desalinated water is also expensive in places that are both somewhat far from the sea and somewhat high, such as Riyadh and Harare. In many places, the dominant cost is desalination, not transport; the process would therefore be relatively less expensive in places like Beijing, Bangkok, Zaragoza, Phoenix, and, of course, coastal cities like Tripoli." After being desalinated at Jubail, Saudi Arabia, water is pumped 200 miles (320 km) inland through a pipeline to the capital city of Riyadh. For cities on the coast, desalination is being increasingly viewed as an untapped and unlimited water source.
Nevertheless, desalination does not take into account recycling water and broken infrastructure. Water is reused in Fountain Valley, CA, Fairfax, VA, El Paso, TX and Scottsdale, AZ. This process is an alternative to desalination that requires 50% less energy due to the significantly lower salt content and produces new water at 30% less cost to the consumer than desalinated sea water without the damage to marine life and ecosystems common to desalination plants.
Israel is now desalinating water at a cost of US$0.53 per cubic meter. Singapore is desalinating water for US$0.49 per cubic meter. Many large coastal cities in developed countries are considering the feasibility of seawater desalination, due to its cost effectiveness compared with other water supply options, which can include mandatory installation of rainwater tanks or stormwater harvesting infrastructure. Studies have shown that the desalination option is more cost-effective than large-scale recycled water for drinking, and more cost-effective in Sydney than the vastly expensive option of mandatory installation of rainwater tanks or stormwater harvesting infrastructure. The city of Perth has been successfully operating a reverse osmosis seawater desalination plant since 2006, and the Western Australian government have announced that a second plant will be built to serve the city's needs. A desalination plant is being built in Australia's largest city of Sydney, and the Wonthaggi desalination plant is a proposed facility in Wonthaggi, Victoria.
The Perth desalination plant is powered partially by renewable energy from the Emu Downs Wind Farm. The Sydney plant will be powered entirely from renewable sources, thereby eliminating harmful greenhouse gas emissions to the environment, a common argument used against seawater desalination due to the energy requirements of the technology. The purchase or production of renewable energy to power desalination plants naturally adds to the capital and/or operating costs of desalination. However, recent experience in Perth and Sydney indicates that the additional cost is acceptable to communities, as a city may then augment its water supply without doing environmental harm to the atmosphere. The Queensland state government recently announced that the Gold Coast desalination plant will be powered entirely from renewable sources, bringing its environmental footprint down, in line with the other major plants that will be operating around the same time, in Perth and Sydney.
In December 2007, the South Australian government announced that it would build a seawater desalination plant for the city of Adelaide, Australia, located at Port Stanvac. The desalination plant is to be funded by raising water rates to achieve full cost recovery. An online, unscientific poll showed that nearly 60% of votes cast were in favor of raising water rates to pay for desalination.
A January 17, 2008, article in the Wall Street Journal states, "In November, Connecticut-based Poseidon Resources Corp. won a key regulatory approval to build the US$300 million water-desalination plant in Carlsbad, north of San Diego. The facility would be the largest in the Western Hemisphere, producing 50 million [U.S.] gallons [190,000 m³] of drinking water a day, enough to supply about 100,000 homes ... Improved technology has cut the cost of desalination in half in the past decade, making it more competitive ... Poseidon plans to sell the water for about US$950 per acre-foot [1200 m³]. That compares with an average US$700 an acre-foot [1200 m³] that local agencies now pay for water." $1,000 per acre-foot works out to $3.06 for 1,000 gallons, which is the unit of water measurement that residential water users are accustomed to being billed in.
While this regulatory hurdle was met, Poseidon Resources is not able to break ground until the final approval of a mitigation project for the damage done to marine life through the intake pipe, as is required by California law. Poseidon Resources has made progress in Carlsbad, CA, despite its unsuccessful attempt to complete construction of Tampa Bay Desal, a desalination plant in Tampa Bay, FL, in 2001. The Board of Directors of Tampa Bay Water were forced to buy Tampa Bay Desal from Poseidon Resources in 2001 to prevent a third failure of the project. Tampa Bay Water faced five years of engineering problems and operation at 20% capacity due to marine life and growth captured and stuck to reverse osmosis filters prior to fully utilizing this facility in 2007.
According to a May 9, 2008, article in Forbes, a San Leandro, California, company called Energy Recovery Inc. has been desalinating water for US$0.46 per cubic meter.[24]
According to a June 5, 2008, article in the Globe and Mail, a Jordanian-born chemical engineering doctoral student at the University of Ottawa, named Mohammed Rasool Qtaisha, has invented a new desalination technology that is alleged to be between 600% and 700% more water output per square meter of membrane than current technology. According to the article, General Electric is looking into similar technology, and the U.S. National Science Foundation announced a grant to the University of Michigan to study it as well. Because the patents were still being worked out, the article was very vague about the details of this alleged technology.
Environmental
One of the main environmental considerations of ocean water desalination plants is the impact of the open ocean water intakes, especially when co-located with power plants. Many proposed ocean desalination plants' initial plans relied on these intakes despite perpetuating ongoing impacts on marine life. In the United States, due to a recent court ruling under the Clean Water Act, these intakes are no longer viable without reducing mortality, by ninety percent, of the life in the ocean; the plankton, fish eggs and fish larvae. There are alternatives, including beach wells that eliminate this concern, but require more energy and higher costs while limiting output. Other environmental concerns include air pollution and greenhouse gas emissions from the power plantsTo limit the environmental impact of returning the brine to the ocean, it can be diluted with another stream of water entering the ocean, such as the outfall of a waste water treatment plant or power plant. While seawater power plant cooling water outfalls are not freshwater like waste water treatment plant outfalls, the salinity of the brine will still be reduced. If the power plant is medium- to large-sized and the desalination plant is not enormous, the flow of the power plant's cooling water is likely to be at least several times larger than that of the desalination plant. Another method to reduce the increase in salinity is to spread the brine over a very large area so that there is only a slight increase in salinity. For example, once the pipeline containing the brine reaches the sea floor, it can split off into many branches, each one releasing the brine gradually along its length through small holes. This method can be used in combination with the joining of the brine with power plant or waste water plant outfalls.
The concentrated seawater has the potential to harm ecosystems, especially marine environments in regions with low turbidity and high evaporation that already have elevated salinity. Examples of such locations are the Persian Gulf, the Red Sea and, in particular, coral lagoons of atolls and other tropical islands around the world. Because the brine is denser than the surrounding sea water due to the higher solute concentration, discharge into water bodies means that the ecosystems on the bed of the water body are most at risk because the brine sinks and remains there long enough to damage the ecosystems. Careful re-introduction can minimize this problem or example, for the desalination plant and ocean outlet structures to be built in Sydney from late 2007, the water authority states that the ocean outlets will be placed in locations at the seabed that will maximize the dispersal of the concentrated seawater, such that it will be indistinguishable from normal seawater between 50 meters and 75 meters from the outlet points. Sydney is fortunate to have typical oceanographic conditions off the coast that allow for such rapid dilution of the concentrated byproduct, thereby minimizing harm to the environment.
In Perth, Australia, in 2007, the Kwinana Desalination Plant was opened. The water is sucked in from the ocean at only 0.1 meter per second, which is slow enough to let fish escape. The plant provides nearly 140,000 m³ of clean water per day.
Desalination compared to other water supply options
Increased water conservation and water use efficiency remain the most cost-effective priorities in areas of the world where there is a large potential to improve the efficiency of water use practices. While comparing ocean water desalination to waste water reclamation for drinking water shows desalination as the first option, using reclamation for irrigation and industrial use provides multiple benefits. Urban runoff and storm water capture also provide benefits in treating, restoring and recharging groundwater. A proposed alternative to desalinization in the state of California and other areas in the American Southwest is the commercial importation of bulk water either by very large crude carriers converted to water carriers, or via pipelines. The idea is politically unpopular in Canada, where governments have been scrambling to impose trade barriers to bulk water exports as a result of a claim filed in 1999 under Chapter 11 of the North American Free Trade Agreement (NAFTA) by Sun Belt Water Inc. a company established in 1990 in Santa Barbara, California, to address pressing local needs due to a severe drought in that area. Sun Belt maintains a web site where documents relating to their dispute are posted online.Experimental techniques and other developments
In the past, many novel desalination techniques have been researched with varying degrees of success. Some, such as forward osmosis, are still on the drawing board now while others have attracted research funding. For example, to offset the energy requirements of desalination, the U.S. government is working to develop practical solar desalination.As an example of newer theoretical approaches for desalination, focusing specifically on maximizing energy efficiency and cost effectiveness, the Passarell Process may be considered.
Other approaches involve the use of geothermal energy. From an environmental and economic point of view, in most locations geothermal desalination can be preferable to using fossil groundwater or surface water for human needs, as in many regions the available surface and groundwater resources already have long been under severe stress.
Recent research in the U.S. indicates that nanotube membranes may prove to be extremely effective for water filtration and may produce a viable water desalination process that would require substantially less energy than reverse osmosis.
Another method being looked into for water desalination is the use of biomimetic membranes
On June 23, 2008, it was reported that Siemens Water Technologies had developed a new technology, based on applying electric field on seawater, that desalinates one cubic meter of water while using only 1.5 kWh of energy, which, according to the report, is one half the energy that other processes use.
Fresh water can also be produced by freezing seawater, as happens naturally in the polar regions, and is known as freeze-thaw desalination.
According to MSNBC, a report by Lux Research estimated that the worldwide desalinated water supply will triple between 2008 and 2020.
Low Temperature Thermal Desalination
Low Temperature Thermal Desalination (LTTD) takes advantage of the fact that water boils at low pressures, even as low as ambient temperature. The system uses vacuum pumps to create a low pressure, low-temperature environment in which water boils at a temperature gradient of 8 to 10 degrees C between two volumes of water. Cooling water is supplied from sea depths of as much as 600 metres (2,000 ft). This cold water is pumped through coils to condense the evaporated water vapor. The resulting condensate is purified water. The LTTD process may also take advantage of the temperature gradient available at power plants, where large quantities of warm waste water are discharged from the plant, reducing the energy input needed to create a temperature gradient.LTTD was developed by India's National Institute of Ocean Technology (NIOT) from 2004. The world's first LTTD plant was opened in 2005 at Kavaratti in the Lakshadweep islands. The plant's capacity is 100,000 liters/day, at a capital cost of INR 50 million (€922,000). The plant uses deep water at a temperature of 7 to 15 degrees C. In 2007, NIOT opened an experimental floating LTTD plant off the coast of Chennai with a capacity of 1 million liters/day. A smaller plant was established in 2009 at the North Chennai Thermal Power Station to prove the LTTD application where power plant cooling water is available..
Thermo-ionic process
In October 2009, Saltworks Technologies, a Canadian firm, announced a process that uses solar or other thermal heat to drive an ionic current that empties all the sodium and chlorine ions from the water.Existing facilities and facilities under construction
Abu Dhabi, United Arab Emirates
- Taweelah A1 Power and Desalination Plant has an output 385 million liters per day of clean water
- Umm Al Nar Desalination Plant has an output of 394 million liters a day of clean water
- Fujairah F2 is to be completed by July 2010 will have a water production capacity of 492 million liters (130 million gallons) per day.
Aruba
The island of Aruba has a large (world largest at the time of its inauguration) desalination plant with the total installed capacity of 42000 metric tons (11.1 million gallons or 42 × 103 m3) per day.Australia
A combination of increased water usage and lower rainfall in Australia has caused State governments to build a number of desalination plants, including the recently commissioned Kurnell Desalination Plant serving the Sydney area. While desalination has been adopted by state governments to secure water supply, it is highly energy intensive (~$140 energy demand/ML) and has a high carbon footprint due to continued reliance on Australia's coal-based energy generation.Cyprus
There are also desalination plants in Cyprus, like the one near the town of Larnaca. This is called the Dhekelia Desalination Plant, which utilises the reverse osmosis system.Israel
The Hadera seawater reverse osmosis (SWRO) desalination plant in Israel is the largest of its kind in the world. The project was developed as a BOT (Build-Operate-Transfer) by a consortium of three international companies: Veolia water, IDE Technologies and Elran.Location | Opening | Capacity (mln m3/year) | Capacity (mln gallons/day) | Capacity (megaliters) | Cost of water (per m3) | Notes |
|---|---|---|---|---|---|---|
| Ashkelon | August 2005 | 111 (as of 2008) | 83.2 | 315 | NIS 2.60 | |
| Palmachim | May 2007 | 30 (expansion up to 45 planned ) | 32.6 | 123.4 | NIS 2.90 | |
| Hadera | December 2009 | 127 | 91.9 | 349 | NIS 2.60 |
| Location | Opening | Capacity (mln m3/year) | Cost of water (per m3) | Notes |
|---|---|---|---|---|
| Ashdod | 2012 | 100 (expansion up to 150 possible) | NIS 2.55 | |
| Soreq | 2013 | 150 (expansion up to 300 approved) | NIS 2.01 - 2.19 |
