New Scientist: Water purification is a costly and energy-intensive process, but scientists are taking lessons from 19th century Mexican communities and employing cactus power to do the job. Researchers from the University of South Florida have discovered that the thick gum used by the prickly pear cactus (Opuntia ficus-indica) to store water also acts as a flocculant, causing sediment and bacteria in the water to settle out. The gum is so effective, it allows 98% of bacteria to be filtered out.
Mexican communities in the 19th century used the gum to filter their water and scientist hope that modern communities in the developing world could also make use of the cactus’ filtration abilities, avoiding the need for costly and complicated filtration systems. Read more.