Water Filters From Clay, Coffee Grounds & Cow Manure

An Australian inventor claims that a handful of clay, yesterday's coffee grounds and some cow manure are the ingredients that could bring clean, safe drinking water to much of the third world. The simple new technology, developed by ANU materials scientist Mr Tony Flynn, allows water filters to be made from commonly available materials and fired on the ground using cow manure as the source of heat, without the need for kiln. The filters have been tested and shown to remove common pathogens including E-coli. Unlike other water filtering devices, the filters are simple and inexpensive to make."They are very simple to explain and demonstrate and can be made by anyone, anywhere," says Mr Flynn. "They don't require any western technology. All you need is terracotta clay, a compliant cow and a match." The production of the filters is extremely simple. Take a handful of dry, crushed clay, mix it with a handful of organic material, such as used tea leaves, coffee grounds or rice hull, add enough water to make a stiff biscuit-like mixture and form a cylindrical pot that has one end closed, then dry it in the sun. According to Mr Flynn, used coffee grounds have given the best results to date. Next, surround the pots with straw, put them in a mound of cow manure, light the straw and then top up the burning manure as required. The manure makes a good fuel because it is very high in organic material that burns readily and quickly.

:: Radio Australia's Innovations

[by Justin Thomas]