Sometimes low-tech solutions make the most sense, particularly in developing countries with limited access to affordable technology. It often happens these same countries experience chronic water shortages, so MIT researchers designed a brilliant solution that relies on nature to clean up after itself. It turns out certain kinds of tree branches, when peeled, rival cilantro’s ability to scrub contaminated water clean of harmful bacteria. In an experiment, they found sapwood is capable of eliminating 99 percent of E.coli bacteria. The same properties that allow xylem tissue to transport sap from a tree’s roots to its crown traps bacteria and other particles over 20 nanometers in size.
“Today’s filtration membranes have nanoscale pores that are not something you can manufacture in a garage very easily,” says Rohit Karnik, associate professor of mechanical engineering at MIT. “The idea here is that we don’t need to fabricate a membrane, because it’s easily available. You can just take a piece of wood and make a filter out of it.”…………..