The Guatemalan association Afaguatemala is promoting the use of a low-cost, artisanal filter to purify water, says the inventor, Gernando Mazariegos. The device, patented in Guatemala, helps reduce the incidence of gastrointestinal diseases and is already being used in 16 countries, among them, Cambodia, Cuba, El Salvador, Ghana, Haiti, Mexico, Nepal and Sudan, Mazariegos said in a Tierramérica interview.

“Its basic components are sand, sawdust and mud, to which colloidal silver is added” as a bactericide, he explained.

The filter, invented by the Guatemalan in 1991, at first glance looks simply like a pot of mud inside a plastic bucket, and costs a little more than 36 dollars in Guatemala's rural areas. But it can filter eight to 10 liters of water a day, which is the average consumption of a family with four or five members.