cool, clear water

OK, this might just be THE technological innovation of the 21st century, with the power to change day to day life for millions of people in the world. Some savvy folks at Australian National University have developed a field procedure where one can combine clay and coffeegrounds into a pot, fire it by piling up dried cow dung around it, and presto, you have a WATER FILTER.

What makes it work? Basically the organic material ends up creating an ultrafine porous matrix in the clay, which is then burned out in the firing process. In the case of coffeegrounds, the most efficacious material used so far, small silica deposits are also made in the clay. The result is a ceramic water filter, but one that can be made with free materials on-hand, instead of being imported and costing approximately $5 USD (a huge sum in many places).

How well does it work? Tests on the filters showed that they removed 96 - 99% of e. coli, putting the water well within safe drinking levels.

Don't have coffeegrounds? It works with rice hull or used tea leaves too, both of which are in abundant supply in areas where these filters are needed most.

Read a transcript of an interview with the inventor for a deeper understanding of the process involved.