Global water usage is growing twice as fast as the population. Could we turn salt water potable on a mass level?
Water, water everywhere and not a drop to drink. That’s (almost) the reality of a planet whose H2O — or at least 97 percent of it — is nonpotable ocean. Much of the remainder is trapped in glaciers, ice caps and soil. In other words, accessible freshwater is scarce — and getting scarcer. But some scientists say this may be changing. As desalination technology advances, the sea may hold the answer to the world’s water crisis. But at what cost?
The desal concept isn’t new — even the ancient Romans used clay filters to separate salt from water in order to make it potable. But there’s never been more incentive for large-scale implementation. Nearly three billion people currently live without access to clean, reliable drinking water. And with the population expected to hit nearly 10 billion by 2050, the problem is set to get worse. According to the United Nations, our water usage is increasing twice as fast as population growth. In America, the average family of four blows through 400 gallons per day. Exacerbated by man-made climate change, water scarcity — the “petroleum of the next decade,” according to Goldman Sachs — will increasingly be a force of international conflict in years to come.
For these reasons, countries around the world are turning to desalination, which usually involves reversing the process of osmosis. Typically, water flows naturally through a semipermeable membrane from an area of low salt concentration to an area of high salt concentration. But, in order for desalination to work, water is pumped in the opposite direction through a very fine (less than a hundredth the diameter of a human hair) synthetic filter. Because brine is left behind, the water becomes usable for irrigation, industrial processes and, yes, drinking.