BBC News: A book with pages that can be torn out to filter drinking water has proved effective in its first field trials.
The "drinkable book" combines treated paper with printed information on how and why water should be filtered.
Its pages contain nanoparticles of silver or copper, which kill bacteria in the water as it passes through.
In trials at 25 contaminated water sources in South Africa, Ghana and Bangladesh, the paper successfully removed more than 99% of bacteria.
Read the full story on BBC News.