The Ceramic Water Filter is a kind of flowerpot made of clay. The clay is mixed with sawdust which, in the heat of the oven, will burn, leaving tiny holes - micropores - inside the clay. Water will seep through these holes. Once the filter is fired in the kiln, it's given a coating of colloidal silver that the Potters for Peace get from laboratories in Zaragoza, at cost price. This material has bactericidal properties, and destroys microbes. This device filters the water, making it crystal clear, and, thanks to the silver, disinfects it by destroying any bacteria that make it through the micropores. The optimal working capacity is the purification of two liters per hour.
The NGO started making these ceramic filters in Nicaragua, and their knowledge has spread around the world. Potters for Peace is in contact with other organizations such as the Red Cross, Doctors Of the World, or Intermón Oxfam for help with distribution, and to teach local potters to make their own Ceramic Water Filter and set up a production capacity. Right now, there are 25 industries of this type in the world, each one serving around seven thousand families.
In each of the countries where the Filter is being made, the potters use materials they already have in their environment, such as clay. Labor is usually cheap, and the harder-to-get materials, such as the colloidal silver, are supplied at cost price, so the final cost of this water-purifier is affordable: in total, seven dollars for a filter with a useful life of between 12 and 18 months. In Zaragoza, one of the suppliers of colloidal silver are the Argenol laboratories.
However, the device must be handled with care since, being made of a porous clay, it's rather fragile. It must be cleaned periodically, too. In any case, and despite being made of clay, there's no risk of it developing any problems through contact with water.
This process of purification has no negative effect on the environment - according to an environmental study in the USA the device generates no contamination or residues, and its contribution to climate change 'has no long-term importance'.