Twenty-five contaminated water sources in South Africa, Ghana and Bangladesh have been cleansed more than 99 percent by a bug-killing book in its first field trials. Its papers successfully killed bacteria with promising effect to filter a person's water supply for four years.
The result, presented at the 250th national meeting of the American Chemical Society in Boston, US, shows the handmade book with treated papers that can be torn out to filter murky drinking water has been succesfully used to kill bacteria. The result shows a single page can clean up to 100 litres of water, and the entire book can provide clean water for a person enough for four years.
The bacteria-killing book was developed by Dr Teri Dankovich, a postdoctoral researcher at Carnegie Mellon University in Pittsburgh. She tested the technology for the book over several years before it was proven effective. The book, also called as the "drinkable book," has the information printed on its pages explaining how and why water should be filtered.
The pages contain nanoparticles of silver or copper which can kill dangerous bacteria as they pass through the water. During the trials, tiny amounts of silver or copper leached into the water, but the amounts were well below safety limits, Dankovich said.
"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 told BBC. The effect occurs when bugs absorb the silver or copper ions, depending on the nanoparticles used, as they infiltrate through the page.
The outcome is primarily directed to the communities in developing countries, where to date, an estimated 663 million people are living without access to clean drinking water, Dankovich said.
Prior to the field tests, the drinkable book was already tested by Dankovich in the lab through artificially contaminated water. In the tests, bacteria levels dropped to zero in artificially contaminated water.
The success of the lab tests led to the field trials which she conducted over the past two years along with charities Water is Life and iDE. In these trials, the number of bacteria in the water decreased by 99 percent on average, and in most samples, it dropped to zero.
"Greater than 90 percent of the samples had basically no viable bacteria in them, after we filtered the water through the paper… 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," Dankovich said.
Dankovich and her team hope to increase the production of the book, which currently is hand-made. They also aim to move on to trials, where local residents use the pages to filter waters themselves.
Dr Kyle Doudrick, an expert studying sustainable water treatment at the University of Notre Dame in Indiana, said the book would be more powerful if it could also tackle non-bacterial infections, such as the tiny parasite cryptosporidium which contaminates water in Lancashire in England.
Out of all the technologies currently available such as ceramic filters and UV sterilisation, the book is a promising one, Doudrick said. The book is cheap and people can easily get hold of it and understand the idea of cleaning water.
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