What if the pages of a book could help clean contaminated water?
Given the fact that 663 million people around the world do not have access to clean drinking water, the need for this kind of innovation is urgent and widespread.
In his Science & Environment article for BBC News, Bug-killing book pages clean murky drinking water, writer Jonathan Webb features a technology being developed by a Carnegie Mellon researcher that is starting to make significant ripples around the globe in terms of access to clean water.
Dubbed a “drinkable book,” the technology combines treated paper with printed information on how and why water should be filtered.
Dr. Teri Dankovich, a postdoctoral researcher at Carnegie Mellon University, developed and tested the technology for the book over several years, working at McGill University and the University of Virginia.
How does it work?
The book’s actual pages contain nanoparticles of silver or copper, which kill bacteria in the water as it passes through.
In trials conducted at 25 contaminated water sources in South Africa, Ghana and Bangladesh, the paper successfully removed more than 99% of bacteria. The results were presented in August at the 250th national meeting of the American Chemical Society.
“It’s directed towards communities in developing countries,” says Dankovich. “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 and wells and out comes clean water—and dead bacteria as well.”
The bugs absorb silver or copper ions—depending on the nanoparticles used—as they percolate through the page.
“Ions come off the surface of the nanoparticles, and those are absorbed by the microbes,” explains Dankovich.
According to her tests, one page can clean up to 100 liters of water. That means a book could filter one person’s water supply for four years.
After successfully testing the paper in the lab using artificially contaminated water, Dankovich went on to conduct field trials over the past two years, working with the charities Water is Life and iDE.
During these trials, the bacteria count in the water samples plummeted by well over 99% on average—and in most samples, it dropped to zero.
“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.
One location gave the paper a particularly tough challenge.
“There was one site where there was literally raw sewage being dumped into the stream, which had very high levels of bacteria. But we were really impressed with the performance of the paper; it was able to kill the bacteria almost completely in those samples,” says Dankovich.
What’s next for the project?
Dankovich and her colleagues are hoping to step up production of the paper, which she and her students currently make by hand, and move on to trials in which local residents use the filters themselves.
“We need to get it into people’s hands to see more of what the effects are going to be. There’s only so much you can do when you’re a scientist on your own.”
Dankovich’s work in Bangladesh is also exploring whether a filter holding one of the book pages could be fitted into a “kolshi”—the traditional water container used by Bangladeshis.
The “drinkable book” has passed two key stages—it works in the lab and on real water sources. Next, the team will need “a commercialisable scalable product design” for a device that the pages slot into. The team also hopes to test the device on non-bacterial infections, protozoa and viruses.
Read the entire article here.
