A team of researchers has completed the first field trials on a book that can be used to filter drinking water, researchers said Sunday at the American Chemical Society national meeting. The “drinkable book,” developed by Carnegie Mellon University postdoctoral researcher Dr. Teri Dankovich, uses treated pages that contain nanoparticles of silver or copper, which kill bacteria in water as it filters through. Trials in 25 contaminated water sources in South Africa, Ghana, and Bangladesh proved successful, removing more than 99 percent of bacteria to produce levels of contamination similar to U.S. tap water, according to researchers. The papers also come printed with directions and why water should be filtered. Each page can clean up to 100 liters of water, which means one book could filter a person’s water supply for four years, according to Dankovich.