Earthy chemistry promises clean water

A very low-tech approach to materials makes a water filter effective in removing common microbes, such as Escherichia coli. The new technology was developed by Australian National University materials scientist Tony Flynn. It uses everyday raw materials, including coffee grounds, clay, and cow dung, which are molded into a filter that can then be hardened without the need for an expensive, energy hungry kiln. The cheap system could bring clean water to millions.