Quenching the Global Thirst for Clean Water

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The Infrastructure Approach

Millions of LifeStraws or ceramic filters, however, will not necessarily solve the drinking water crisis. "I don't see that there's going to be one silver bullet solution for the world's water," Murcott says. And ultimately, "the solution to unsafe drinking water is bigger than a technology solution," she asserts.

The aspiration is to establish water-treatment plants and utilities like we have in the developed world throughout remote regions of Africa, Latin America, Southeast Asia, and elsewhere, maintains John Briscoe, of the Harvard School of Public Health, who has been working in the field of environmental health and engineering for four decades. But "that's incredibly unsexy," he confesses. It requires economic growth and relative stability—tall orders for many regions, but ones that will bring with them myriad other improvements, such as jobs, transportation, and medical care, in addition to clean water. Piecemeal approaches such as point-of-use filters, he notes, are addressing the symptoms rather than the causes of water insecurity. And that, he argues, can even distract from and slow down development of crucial larger water-infrastructure projects. It is a hard position for many to swallow, he says, but many government or aid- organization attempts to improve water access—with filters or one-off cleaning powders—fail to result in more lasting changes in the affected areas of the globe.

Saltwater and Wastewater Solutions

Where climate, geography, and other factors make fresh water scarce, many places are already running off the freshwater grid. For example, Saudi Arabia and Singapore are among the more than 120 countries using desalination to create some of their drinking water. The most basic method of desalination has been in practice for centuries and requires simply boiling salt water and gathering the purified water vapors to condense back down into potable water. A less energy-intensive process that is becoming more popular simply filters the salt out of the water using a super-fine mesh membrane, which has the added benefit of removing other contaminants at the same time. Utilities are already using this technique in Israel, Hong Kong, and El Paso, Texas. Research groups and forward-looking companies are now also enlisting artificially made proteins to extract the salt from water. These proteins work like those in our own bodies that move water out of cells; they have a positive charge on one end that repels salt molecules and prevents them from passing through the membrane. Earlier this year, a Danish company named Aquaporin acquired a patent in the United States for a version of this protein-based desalination technology.

For the landlocked, successful water reuse has finally arrived, which means that—if the public can stomach it—engineers can turn wastewater back into drinking water (by filtering out solids and then pushing the water through super-fine filters to remove bacteria and other contaminants before it is disinfected further via UV light, hydrogen peroxide, and other treatments). Some localities, such as Orange County, California, and El Paso, are pumping treated wastewater underground to replenish freshwater aquifers. Others, including cities such as San Diego and Windhoek, Namibia, are pumping this recycled water directly back into the main public supply.

Of course, climate change, with its contaminating floods and devastating droughts, will further stress the planet's resources. And the proliferation of new contaminants, such as pharmaceutical compounds from consumer and agricultural wastewater that have been found in the United States, Europe, and Southeast Asia, will continue to push us to develop new and smarter filtering approaches.

Here in the U.S., for example, agricultural runoff, industrial pollutants, and other manmade hazards—such as risks to well water near hydraulic fracturing sites—also play a part. Concerns over these threats and others have pushed at least 4 out of 10 American households to use some sort of home filtering, according to a 2005 study by the EPA.

Yet, says Patricia Toccalino, a water-quality expert with the U.S. Geological Survey, "the U.S. has one of the safest drinking water supplies in the world." And for the rest of the world, Briscoe notes, more than a quarter million people each day are already gaining access to better drinking and cooking water. Something to raise a glass to, indeed.

Katherine Harmon is a writer living in Brooklyn, New York. She is currently an associate editor at Scientific American. Her first book, about octopuses, will be published in 2013 by Current, a division of Penguin.

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