[2] Rivera first became passionate about ceramics in the early 1970s when he studied in Cuernavaca, Mexico with Paulo Freire and Ivan Illich, who taught that human beings had lost their connection with the earth.
Rivera produced this inexpensive filter developed in Guatemala by Mr. Mazariegos from a mix of local terra-cotta clay and sawdust or other combustible materials, such as rice husks.
This combination of fine pore size and the bactericidal properties of colloidal silver produce an effective filter, killing over 98 percent of the contaminants that cause diarrhea, thus dramatically reducing public health problems in the communities that use them to purify potable water.
[2][3] Rivera began manufacturing the pots through Potters for Peace in Nicaragua, eventually helping to establish an independent enterprise to produce the filters.
[6] Beginning in 1998, Rivera traveled throughout Latin America, Africa and Asia to establish 30 filter microenterprises in Guatemala, Honduras, Mexico, Cambodia, Bangladesh, Ghana, Nigeria, El Salvador, the Darfur region of Sudan, Myanmar and other countries.
[2] Rivera wanted to share this Guatemalan invention with the world and posted his experience in manufacturing ceramic pot filters in painstaking detail, on the Internet.