ASHKELON, Israel -- Abraham Tenne tilts his head upward and takes a gulp of water from a paper cup. But this isn't your average cup of water. It's just come directly from the briny Mediterranean Sea. At the Ashkelon Desalination Plant, a 28-acre complex some 40 miles (70 km) south of Tel Aviv, 15,000 to 16,000 cubic meters of seawater is converted into fresh water every hour -- if you can imagine it, that's about 15 to 16 million one-liter plastic bottles. The plant churns out 15 percent of Israel's yearly water supply.

The technology that turns the sea into fresh, potable drinking water isn't new, but now it's changing the game for Israel, where a severe water crisis threatens the country's very existence.

The country's population of 7.8 million people is growing at a rate of 1.8 percent a year. Meanwhile, severe drought has plagued this largely desert nation over the past decade -- it's been so severe that Tenne, chairman of Israel's Water Desalination Administration, compares it to biblical misfortunes: "If you remember the story of our ancient fathers who had seven good years and seven bad years in the time of Moses, in Egypt, we had the same seven years. Only it was in the last seven years."

Although in 2012 the country experienced a cold and wet winter that caused water levels to increase once again, there's no expectation the water shortage will end anytime soon.

That's because Israel's aquifers have been drying up, and the Sea of Galilee, known here as Lake Kinneret, which supplies the country with 35 percent of its freshwater needs, has fallen to extremely low levels, creating a large gap between supply and consumer demand. Officials believe it is only going to get worse unless something drastic is done.

"We will need to close the gap", Tenne says.

But How Much Does It Cost?

Enter desalination, which is typically considered the most expensive way to get fresh water. But in Israel, the benefits outweigh the costs.

Tenne says the cost may be a misconception. He is the co-author of a study presented this year that notes that large-scale desalination increases economic activity by employing people to construct, operate and maintain the plant, and it also reduces water hardness. "You have to take into account the difference of the cost of water minus the benefits you are gaining from the water," says Tenne.

Water desalination is just one of a host of technologies Israel employs to conserve what it considers a vital resource. The country is  a world leader in recycling waste water, reusing over 80 percent of what is known as treated waste water, or approximately 400 million cubic meters a year, far beyond that of any other country. By comparison, Spain, in second place behind Israel, recycles 20 percent of its waste water.

Additionally, Israel is considered a leader in drip irrigation techniques. About 90 to 95 percent of its agricultural sector uses drip irrigation, says Tenne, compared to less than 7 percent in the United States, according to the International Commission on Irrigation and Drainage. Tenne says Israelis educate their children on water conservation so that they become what he calls "an army of water policemen," reminding their parents to shut the tap every time they brush their teeth or shave.

Yet, despite the country's emphasis on education and innovative water conservation technologies, the water shortage continues to be pervasive.

The crisis is pushing the Israelis to invest billions in a long-term national water plan that would have the public and private sectors work  together. In the case of Ashkelon, for example, the cost of building the plant, the equivalent of more than $200 million, was shouldered by VID, a joint venture of Israeli-based IDE Technologies, Dankner-Ellern and France's Veolia(NYSE:VE). In turn, the Israeli government promises to buy a certain amount of water annually from the plant operators, and it will assume ownership of the site in 2027.

Israel currently has three large-scale desalination plants in operation, along its Mediterranean coastline: Ashkelon, Palmachim and Hadera. The latter was built in 2009 and surpassed Ashkelon as the largest reverse osmosis water plant in the world, producing 140 million cubic meters of water every year. Another Israeli plant at Sorek, scheduled to open in mid-2013, is expected to be bigger still.

By the end of next year, the country's national water authority plans to expand Palmachim and open a fifth plant at Ashdod. The new water plan may even leave the country with some reserves so it can be less reliant on pumping water from aquifers and the Kinneret, and allow them to replenish their levels naturally.

Currently there are more than 20,000 water desalination plants across the globe, and Israeli authorities believe there will need to be many more to accommodate the growing demands of seven billion people.   

"The main issue for the future of the world is the water crisis," said Gilad Erdan, Israel's Minister of Environmental Protection. "Everyone understands we will need much more water in the future." That's the approach Erdad pitched in June at the Rio Earth Summit. But desalination isn't free from environmental costs and dangers. 

No Power, No Fresh Water   

First, saltwater is pumped directly from the Mediterranean, with three large undersea pipes sucking in vast amounts of water, which is then filtered. After it is cleaned, the seawater is pumped into a warehouse-like building that resembles an airplane hangar and is home to 50,000 membranes that separate the water molecules from the salt in the water through reverse osmosis under high pressure, about 30 to 35 times the pressure of a car tire.

Fifty percent of the seawater ends up as drinking water and the other fifty goes back into the sea as a concentrated brine. The last stage in the process is adding minerals, such as limestone, back into the fluid to make it taste like what we know as water.

But where does the salt go?

Initially, when it is harvested from the sea, the water is about 4 percent salt, and when the concentrate is returned it contains about 7.5 percent salt, roughly double the average salinity of the world's oceans. On top of that, environmentalists have raised concerns about a large red plume in the sea caused by the high iron content of the concentrate sent back into the Mediterranean.

Israel is a member of the Barcelona Convention, a landmark treaty between 22 countries to assess and control marine pollution. Tenne says his agency is monitoring the water, the seabed and biological population near the plant, and new, more stringent regulations have put greater controls on how the concentrate is sent back to sea. Overall, the industry is placing a growing emphasis on reducing the amount of chemicals in the process, finding better ways to remove water from the sea and how to return the salt concentrate back to the sea without killing marine life, according to Tom Pankratz, a Houston-based independent consultant and editor of Global Water Intelligence's weekly Water Desalination Report.  

Israel's Minister of the Environment, Erdan, says the country's water needs are too important to give up desalination because of environmental concerns. We have to make sure the quality of the brine fits the demands of the international community. The dilemma is whether to give it up, and then you don't have water, or try to improve the desalination technologies. The new Sorek plant will feature water intakes and exhausts that will be less damaging to the environment.

Then there's energy use. Desalination has traditionally been done with thermal distillation plants, power-hungry monsters that generate lots of greenhouse gases. Like a teakettle, thermal plants boil seawater to create steam, then the water is cooled so the steam condenses and forms pure water. This heating and cooling requires about 6 to 7 kilowatt hours per every one cubic meter of desalinated water produced -- but innovations in reverse osmosis technologies now make it possible for Israel to produce one cubic meter of desalinated water for roughly every 3.5 kilowatt hours. That's the equivalent of what one air-conditioner needs for one hour of operation, and it's enough to produce water that meets the average person's needs for a week.  

Mixing Hamas And Water

The experts, in fact, admire Israel's proficiency in desalination technology. Pankratz says that "people tend to be conservative, and some new technologies have been slow to get to market in this industry, but Israel has done an amazing job of rolling out and implementing the new ideas," he said, adding that "Israeli companies build desalination plants fast and relatively affordably."

Israel's desalination push isn't taking place in a vacuum, though -- the country is in a volatile part of the world, where some experts predict that conflicts over water rights will exacerbate the precarious political situation as populations grow. Already tensions with Hamas, the Palestinian party in control of Gaza and with which Israel has no formal relations, have created a number of ongoing security concerns at the Ashkelon plant. Some fear it could be the target of a terrorist attack, or that sewage from nearby Gaza, which lacks water treatment facilities sufficient for its booming, penned-in population, could disrupt plant operations. And overall, there's the threat of population growth too steep for even improved desalination to keep pace with: "It's not a magic solution," acknowledges Erdan. 

Still, the new technology is a huge leap: When Israel's new plants go online in 2013, the country's total capacity will be roughly 600 million cubic meters of water annually, or almost 50 percent of its drinking water needs. That's one glass of water out of every two coming from the sea.