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Friday, October 30, 2009

Clean Water Everywhere: DIY Clay Water Filters

By Jasmin Greene

By Care2 .com

clay photo

Aaron Lindberg/Getty Images

Do It Yourself | Health | Water

Clean drinking water has always been a major issue in many developing countries, but with the onset of climate change and droughts, this may become a problem for industrialized countries as well. There is a simple solution for clean water: clay. Tony Flynn with the World Vision charity and Potters for Peace have discovered people everywhere can drink clean water with the materials around us.

Tony Flynn, a master potter and scientist, has created a simple to create water purifier out of incredibly simple materials found almost anywhere in the world. The filter is created with clay, organic materials (coffee grinds or rice), water and manure. The straw and rice are mixed in with the clay and water and then fired over some burning manure. 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 [Source: ANU]. One of these filters can great a liter of drinkable water in only two hours. You can make your own filter by following these steps:

1. crushed, dry clay
2. organic material(tea leaves, cofffee grounds, or rice hulls)
3. water
4. Cow manure

1. Mix in enough water to make a stiff biscuit-like mixture
2. Form a cylindrical pot that has one closed end
3. Dry the pot in the sun
4. Surround the pot with straw and place it in a mound of cow manure
5. Light the straw and then top up the burning manure as required.
6. Filter will be completed in less than an hour.

This invention was purposely not-patented so that everyone could create their own water filters. Other organizations like Engineers Without Borders and Potters for Peace have introduced a similar clay filter designed by Guatemalan chemist Fernando Mazariegos. The filter follows the same idea as the one created by Tony Flynn, but fires the clay inside of a kiln rather than over an open fire and paints the filter with colloidal silver afterwards. The silver helps to remove bacteria and pathogens that traditional clay filters might otherwise miss [Source: Gazette Times].

While clay filters are easy to create and much environmentally friendly, there are some downfalls. One of the major disadvantages is that they can only produce a small amount of water and that if the water is turbid, then the filter needs to be scrubbed after use. This abrasive treatment wears away the ceramic and may even crack the ceramic. Any cracks would allow pathogens to short circuit the filters. Clay filters may be cheap to produce, but if the surface water that they are treating is highly turbid the filters may have a relatively short life [Source: RELFE] and need to be replaced at a very high rate.

Despite these flaws, clay filters are gaining in popularity and countries like Ghana and Cambodia are producing thousands of these for distribution per year. Clean drinking water does not have to a problem in the future if we take precautions not to pollute our water or climate.

How to Go Green: Water


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