FROM TAP TO TOILET: At least 2.6 billion people worldwide do not have access to adequate sanitation--meaning discomfort, disease and death.
©John Montgomery-Brown/istockphoto.com

Sanitation doesn't get a lot of headlines but, all told, its absence kills 6,000 children a day, according to British charity Water Aid. And the solution chosen by the developed world—the flush toilet—is running up against limits in the amount of water available to flush away human waste.

The United Nations has attempted to fill this gap by securing a pledge from developed countries to halve the number of people without any form of sanitation—whether basic outdoor latrines or indoor toilets—by 2015 as part of  its Millennium Development Goals (a series of goals for world development, ranging from alleviating poverty to fighting diseases like AIDS). To accomplish this task, however, a toilet would have to be installed every second between now and then, according to the U.N.

As a result, this objective may be the furthest of these goals from being realized. At present rates of progress, sub-Saharan Africa, for example, would only reach the target by 2076, according to Water Aid. And the developed world is in no better shape: U.S. Environmental Protection Agency estimates predict a $122 billion spending shortfall on wastewater treatment necessities between 2000 and 2019.

In an effort to better understand this sanitation crisis, Scientific American's David Biello spoke with Rose George, author of The Big Necessity: The Unmentionable World of Human Waste and Why It Matters. (Read an excerpt here.)

What inspired this book? Why toilets?
It was kind of a gradual process. … I was introduced to Dr. Bindeshwar Pathak of Sulabh [a non-governmental organization devoted to sanitation] in India. He was a Brahmin [member of the highest Hindu caste] who devoted his life to saving untouchables [the lowest caste] from the horrible job of cleaning dry latrines with their bare hands. His life's work was installing half a million public toilets, which American tourists have probably enjoyed.

Right now, 2.6 billion people have no toilet, not even a bucket. That's four in 10. And diarrhea kills more children under five than TB, HIV and malaria combined. I found that absolutely shocking. And I found these people who I came to admire, kind of sanitation foot soldiers like Dr. Pathak, trying to do their bit. It's a colorful cast of characters. Dr. Pathak also set up the International Museum of Toilets—the biggest toilet museum in the world—which is one room in New Delhi.