The World Health Organization (WHO) estimates that the total number of people without access to clean drinking water now stands at 663 million; each year, more than 840,000 globally die from water-related diseases. A key challenge in developing effective water filter technologies has been making them cheap and portable for distribution to those who need them.
Enter The Drinkable Book™— a patent-pending water filter technology that produces clean drinking water by passing contaminated water through a thick sheet of paper embedded with silver nanoparticles; these nanoparticles have antimicrobial properties, killing more than 99 percent of bacteria as they pass. The filtered water meets US EPA bacteria guidelines for clean drinking water.
A single page from The Drinkable Book is capable of filtering 100 liters of water, meaning a single book can supply a person with cleaning drink water for roughly four years. The books cost only dollars to produce, but the team behind it needs help in bringing the technology to scale: pAge Drinking Paper, the non-profit organization behind The Drinkable Book, has launched an Indiegogo campaign to trial the filter papers in two villages for a month, as part of their aim of evaluating their performance across a range of countries. The fundraising campaign has raised just over US$9,000 of its US$30,000 target so far — enough to supply the equipment, paper and personnel to trial the drinking papers for one month.
We caught up with pAge Drinking Paper founder Dr. Theresa Dankovich to hear more about the filters’ potential and forward plans.
If I understand correctly, the Drinking Paper is embedded with silver nanoparticles that kill the microbes in dirty water. Does this target all potentially harmful bacteria to make it suitable for drinking?
Teri Dankovich: Silver nanoparticles are non-specific antibacterial agents. In the scientific literature, silver has been shown to kill all sorts of bacteria, including E. coli, Listeria, pseudomonas, salmonella, staphylococcus, streptococcus and cholera.
You developed this technology through your PhD research at McGill University, and I suspect you spent a number of years testing its capabilities under the controlled conditions of a laboratory. How have the results compared when tested against the complex nature of real-life waters? How does the paper withstand complications such as sediment-laden waters?
TD: We found that in both laboratory and field analyses of these filter papers that there were high levels of bacteria reduction, greater than 99.9 percent. There are many differences in laboratory-prepared bacterial suspensions and natural water sources. Laboratory tests can often overestimate the numbers of bacteria present in natural waters. For example, in wastewater the level of bacteria is typically in the millions of counts per milliliter, and because of this potentially high contamination, laboratory tests are designed to evaluate the worst-case scenario. The typical levels of bacteria in surface waters (rivers and lakes) are usually less than 2,000 counts per milliliter. Overall, natural water sources differ by being much more variable in levels of bacteria. In terms of turbid water (sediment-laden water), the paper can still function to eliminate bacteria, but would typically filter more slowly.
Are there any potential issues with waste management or toxicity once the pages have been used?
TD: As the filters are used to purify water, a small amount of silver is leached into the filtered water. The level is lower than the recommendations by the WHO and the EPA, but is not zero. As the filters are used to clean many liters of water, the total amount of silver in the filter papers will decline. At a certain point, the antimicrobial effectiveness of the filters declines to loss of the active ingredient — silver. Because of this, we do not anticipate issues with waste management.
How can users tell when the antimicrobial effectiveness of the silver nanoparticles has been depleted, such that they need to switch to a new filter sheet?
TD: We are working on developing some sort of indicator embedded into the sheet that could cause a color change or loss of color over time. For the time being, printed on the pages of the Drinkable Book give specific recommendations for the length of time and number of liters that the filter can handle.
There is a range of viable water-filtration technologies, but a key stumbling block is in making them cheap enough for wide-scale use by those who need them. The beauty of the pAge Drinking Paper seems to lie in its low cost and portability. How much is a Drinking Book likely to cost?
TD: We aim to keep costs as low as possible, and the goal is to create these filters to cost less than ten cents each. Ideally, these filters would be sold in regular marketplaces. The Drinkable Book™ contains 50 filters, so our target would be US$5 for the paper materials cost, and ideally less than US$10 with the printing and binding included.
What kind of reception have the drinking books received from local communities?
TD: In rural communities in Southern Bangladesh, people wanted to purchase and know when the filters would be available for purchase. They were very interested in how the filters work and ways to use them in their current household practices. Often villagers guessed that the filter was made from carton paper or animal hide! In general, the reception has been very positive.
What are next steps in bringing this to scale? How far is the technology from commercialization and mass rollout?
TD: While we ultimately want to be able to provide water to tens to hundreds of millions of people, we must first do development work to create a practical product and demonstrate that it works in the hands of users in faraway countries. The next step in the project is scaling up production at pilot paper facilities and field testing to distribute filter papers to hundreds to thousands of people. We plan to perform a field trial of the papers for 1-2 months in about a dozen villages. Follow-up on these field trials will refine our filter prototypes to achieve a final product.
If all goes well, we hope to finalize the development work within the next couple of years.
The Drinkable Book’s Indiegogo campaign continues through September 17, 2015.