A woman in Africa walks 3.5 miles to get water for her family, each member of which will need at least 2 gallons a day. Almost 1 in 3 people in Tajikistan rely on easily contaminated open ditches and canals for household water, putting them at risk for disease. Around the world, some 800 million people lack access to clean water to drink or cook with, according to official statistics from the World Health Organization (WHO) and the United Nations. And some experts estimate that the actual number of people using water that is unsafe might be closer to 1.8 billion. More than 2 million people still die each year from consuming contaminated water. And millions of people who live in water-insecure areas—whether in Asia or here in the United States—already depend on large-scale recycled or desalinated water supplies as part of their daily intake.
The millions who remain at the highest risk lack access to "improved" water sources, meaning that the crucial resource is not piped in or even collected from a protected spring or well. Thus these people are forced to use untreated and unprotected water for drinking, cooking, and washing. Though some of these dangerous sources are visibly dirty—surface water, or a muddy ditch, for example—other sources may look crystal-clear yet harbor hazardous bacteria, viruses, and parasites. Even water that is thoroughly clean when collected is frequently contaminated at home due to insufficient sanitation and hygiene. Tragically, children are the most vulnerable: Most of the illnesses and deaths caused by dirty water strike those under the age of 5, notes the WHO.
But today, technologies—some high-tech and some elegantly simple—are helping to bring safe water to people who have never had it. Thanks to innovations such as desalination, which is already in use in Asia, the Middle East, the United States, and elsewhere, and a wide range of filters, such as ceramic pots designed for at-home decontamination that are being made and used in Africa and South America, the world's drinking water crisis might finally be starting to dry up.
21st-Century Innovations for Individual and Community Use
For those across the globe still in need of a drink of clean water, many of the world's smartest minds are finding ingenious ways to make dirty water clean—and in some of the most challenging locations.
One such innovation derives from the age-old—and still common—practice of boiling water to disinfect it. Known as solar disinfection, a new approach is being championed by the WHO, Red Cross, and UNICEF, for individuals in at least two dozen countries, including remote, rugged areas in Guatemala, Kenya, and India. Refilling recycled plastic water bottles and leaving them laid horizontally undisturbed in the sun for a day can render water free of microbial contamination. UV-A rays kill off common bacteria such as E. coli. And if the water gets hotter than 122 degrees Fahrenheit, it can also inactivate any amoebas that can cause dysentery and other diseases that pose serious health threats, especially in regions of Africa where medical facilities are few and far between.
Susan Murcott, an engineering lecturer at the Massachusetts Institute of Technology, has been working for the past seven years in northern Ghana to increase the use of ceramic pot filters, which can filter out both microbial and sedimentary contamination using gravity. These pots are manufactured and sold locally and come with a safe water storage container and tap to minimize the chances for recontamination. Factories for these filters are now springing up elsewhere in Africa as well as in South America.
Other filtration technologies include LifeStraw, an oversize plastic straw that contains hollow fibers that function as filters, so a person can use it to drink directly from a microbially contaminated water source. The straw can satisfy one person's drinking-water needs for about a year before the filters get clogged (filtering approximately 264 gallons of water). A larger, gravity-based version can clean water for a family on any continent to meet U.S. EPA standards, and an even bigger iteration for use in schools is currently in the works.
More complex chemistry is also being used to clean water for millions—many of whom live in politically unstable or hard-to-reach areas of South Sudan, Rwanda, and Ethiopia. For example, PUR, a brand better known for first-world home filters, developed a powder that contains safe iron sulphate and calcium hypochlorite. These compounds kill bacteria and viruses, which then clump together with any dirt and particulate matter that are in the water, making it easy to remove or filter out. One packet can clean 2.5 gallons of water in about half an hour.
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.