Wat-a-filter! 01/06/2010
 
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Every year millions of children die of water-borne diseases. A scientist from Australia has developed a filter, that's as easy to make as it is to use, with clay, coffee and, believe it or not, some good ol' cow dung. He created this technology in 2005, and it has never been patented, so that it is used freely wherever required in the world.

Tony Flynn, an artist, potter and materials scientist at the Australian National University (ANU), realised that water-borne diseases such as diarrhea destroy numerous lives, especially in the developing world. Most water filters consist of a hollow ceramic vessel filled with charcoal. These filters are usually imported from foreign countries, and out of reach for the people who need it the most. This filter uses normal clay, found freely anywhere in the world, mixed with coffee. The clay on its own is too dense to allow water through. When the clay is mixed with coffee in equal parts, and fired, the coffee creates holes in it, making it porous. 

Firing of clay is an expensive affair requiring a kiln, and Tony knew this would not be practical. Wood too, is not always easily available. He realised that cow manure is the ideal material as a dung fire burns at 950˚C, perfect for baking clay. After around an hour of baking in the dung, the filter is ready to use. When tested the filter removes between 94.6 and 99.8% of e-coli in water. The tiny holes of the filter are too small for bacteria to go through. However, particles from the clay itself, and some viruses can pass through the filter. "It's not a golden bullet but it's a bullet nevertheless. It will help where there's nothing else available." Mr. Flynn elaborates. According to the ANU, 'the organic materials are burned away during the firing process and create small passages in the filter that allow water, but not pathogens, to pass. This filter effectively removes 96.4-99.8% of E. Coli in water.'

This invention was born out of a World Vision and Potters for Peace project in East Timor, to rehabilitate a small potter community, Manatuto, that had been displaced by the constant violence of East Timor's civil war. The idea was empower the potters to make their own filters, and maybe even sell them for income. 

The simple materials, and the firing with cow-dung ensures this is a 'zero-technology' process, available whenever needed. Tony Flynn sums it up,"“Everyone has a right to clean water, these filters have the potential to enable anyone in the world to drink water safely."

By Armeen Kapadia
 


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