MIT scientists show tree branch to be effective water purifier

Brooks Hays upi.com BOSTON, Feb. 27 (UPI) -- Dirty, contaminated water is a problem for many developing nations. But water filters are relatively expensive and not something easily assembled in the shed, garage or backyard -- unless, of course, the water filter is already assembled and growing in the backyard. New research by scientists at MIT proves that a water filter made out of a small piece of sapwood from a white pine tree can rid contaminated water of 99 percent of the bacteria E. coli, producing up to four liters of clean, potable water a day. They say the small pores of a sapwood branch or section of trunk -- tissue that's designed to transport sap throughout the tree -- works to trap and block most types of bacteria as water filters through. The details of the researchers' discovery was recently published in Plos One. “Today’s filtration membranes have nanoscale pores that are not something you can manufacture in a garage very easily,” explained Rohit Karnik, co-author of the new study and 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.” to read more: upi.com