A "drinkable" book containing pages that can be removed and used to filter drinking water has been effective in its initial field trials, its developers say.

The book, with instructions on how to use it printed on each page, has been successfully tested at 25 contaminated water sites in Bangladesh, Haiti, Kenya, Ghana and South Africa.

Its pages, with instructions in English and the appropriate local language, are coated with nanoparticles of copper or silver that kill bacteria in the water as it passes through them.

Each page can be torn from the book and inserted into a special holder into which water is poured and filtered.

The metal removes 99 percent of dangerous microbes, and even though tiny amounts of the sliver or copper do leech into the filtered water, the resulting metal levels are well below U.S. guidelines for safe drinking water.

A single page of the book can filter and purify around 25 gallons of water, and one book can filter enough water for one person's needs for 4 years.

The Drinkable Book is the brainchild of Theresa Dankovich of Carnegie Mellon University in Pittsburgh, who has teamed up with a nonprofit organization, WATERisLIFE, to mass-produce them.

"It's directed towards communities in developing countries," she says, noting that 663 million people around the globe are without access to a source of clean drinking water.

"All you need to do is tear out a paper, put it in a simple filter holder and pour water into it from rivers, streams, wells etc. and out comes clean water – and dead bacteria as well," she explains.

Successful laboratory trials led to 2 years of field trials.

"It's really exciting to see that not only can this paper work in lab models, but it also has shown success with real water sources that people are using," says Dankovich, who presented the results of her work at the national meeting of the American Chemical Society this week.

It meets the need for an inexpensive, simple-to-use and transportable method for purifying drinking water, she says.

The developers say they are working on easily accepted and culturally appropriate designs for the filter holders.

"Worldwide, many people use a 5-gallon bucket for many needs, so we are basing our approach on that type of container," Dankovich says.

The focus now is on going from limited production of experimental prototypes to full-scale manufacturing, she says.

"We have to go from 'cool chemistry' to something everyone can understand and use," she says.