Plant Xylem Water Filter

MIT Researchers Discover Natural Solutions for Filtering Water

Plant Xylem Water Filter
Copyright: © 2014 Boutilier et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Ads and commercials for water filtration systems today seem to be based on the future and the products themselves even look like technologically advanced. However, a new study is finding that getting clean water might not require super-advanced filters after all. At MIT, a team of researchers led by Rohit Karnik has found that trees, white pine in particular, can be used as a biodegradable and less-expensive water filtration option.

“There is a community of people who do look at sap flow and drying in plants because it’s obviously important, but that community doesn’t intersect with the water purification community,” said Karnik, an associate professor of mechanical engineering at MIT. “They are thinking about how plants work and not how we can use plants to accomplish something else.”

When researchers passed water through the sapwood in tests, they discovered that it was able to filter over 99% of the E. Coli that was present. The initial hypothesis is that the tissues of the wood that allow sap to pass through do the same for water while blocking most types of bacteria.

“Some of the most powerful pollutant filtration is found all around us in nature,” says Steve Scheer, President of Brondell Inc. “Various plants and animals already act as organic filters. Think of oysters in a bay actively filtering and cleaning the water around them. As we study and learn more about how they work, we can incorporate this technology into our next generation designs.”

But though the study looks promising, going out and turning a stick into a straw isn’t necessarily a good idea. Because viruses are smaller than bacteria, they could still work their way through the natural filters, causing serious illnesses. Plus, the system is not yet very time-efficient, since it took about an hour for the filter to produce just a small vial of water. In the future though, as the process is fine-tuned and perfected, it could become more viable.

“We would like to see this developed further, so we are seeking funding to develop this into filtration devices,” Karnik said. “We did not file for a patent. I just felt one shouldn’t patent something that’s so universal, but I think that how do we process xylem or how do we make filters out of it—that’s where I think there’s a lot of potential to develop this technology.”

Over time, it will be interesting to see if the seemingly primitive technique can be used in home filtration systems. Certainly, funding will play a role if it ever does.