Advances in Desalination

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SEATTLE — The U.N. reports that the world’s population will rise to 8.6 billion people by 2030, so scientists need to be vigilant in both monitoring Earth’s most necessary resources and finding ways to prolong them. As fresh water becomes more scarce as populations grow, advances in desalination are necessary for keeping up with this global population increase.

At least 26 countries in Africa are predicted to double in population by 2050, and India is on track to surpass the world’s largest populated country of China by 2024. Nigeria is likely to go from ranking seventh to surpassing the United States as the third-most populated country in the world.

Climate change alone is leaving hundreds of millions with significantly less access to long-held freshwater sources. There are currently more than 1,800 desalination plants operating in 150 different countries around the world, using several methods to convert salt-rich ocean water into fresh drinking water. The most utilized method is membrane distillation, in which heated salt water and cold freshwater are sandwiched between a porous membrane. This naturally draws fresh water vapor from the salt water.

The Rice University Center for Nanotechnology Enabled Water Treatment (NEWT) is currently working on its own advances in desalination with a solar-powered desalination plant. The technique is called “nanophotonics-enabled solar membrane distillation” and combines the more traditional membrane distillation technique with light-harvesting nanophotonics that convert sunlight to heat. According to an article from Science Daily, NEWT’s goal is “to develop compact, mobile, off-grid water treatment systems that can provide clean water to millions of people who lack it and make U.S. energy production more sustainable and cost-effective.”

Meanwhile, Singapore strives to change the perception of conventional desalination plants. Its Keppel Marina East development plant (to be completed in 2020) will have a more modern design, with a 20,000 square-meter lush garden set to be used as a community recreational area. It will use collected rainwater from the green roof to supply the facility’s water needs as well as irrigate the area.

Water availability in India is predicted to decline by 50 percent per person every year between 2001 to 2050. Harsh Vardhan, the Indian minister of earth sciences, reports having embarked on a “desalination mission,” according to an article by Water and Wastewater International. There are a few desalination plants in the country, but they will have to improve significantly to keep up with the growing demand for fresh water in a rapidly growing country.

The Sorek Desalination Facility provides the water-scarce Israel with 10 percent of the country’s drinking water as well as 20 percent of domestic water. It is currently the world’s largest desalination plant with a seawater treatment capacity of 624,000 cubic meters per day. Water Desalination Administration (WDA), an Israeli Governmental agency, launched its “water desalination master plan’ in 2000, and envisions tripling that number to 650 million cubic meters per year by 2020.

Environmentalists criticize desalination due to the procedure’s high energy cost and ecological footprint, while marine biologists note the risk to ocean biodiversity. Traditional water sourcing from freshwater bodies is much more environmentally friendly and is optimal to continue in a perfect world. The fact of the matter is that this may not be enough, especially with desert regions and increasingly populated areas where advances in desalination techniques may be the only option.

The solution is to find an environmentally friendly desalination technique in the future. Scientific American writes, “Of course, as supplies of fresh water dwindle, the economic cost of desalinization, especially in coastal areas with easy access to ocean water, begins to look competitive with traditional water sourcing.”

Katherine Gallagher

Photo: Flickr

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