A step closer to standardized manufacturing practices for ceramic water filters

Nearly a billion people do not have access to an improved water supply (UNICEF/WHO 2008). Hundreds of millions drink water contaminated at the source or during collection, transport, and storage. Diarrhea, one health consequence of unsafe drinking water, kills 1.87 million children each year (Boschi-Pinto et al. 2008).

Recognizing this global health challenge 30 years ago, Dr. Fernando Mazariegos conceived the idea of engaging local artisans to manufacture a ceramic water filter that could be distributed in rural communities. After two years of research and field trials, with funding from the Inter-American Development Bank, the ceramic water pot (CWP) filter was developed. These filters met the objectives of being produced with local raw materials, at low cost, using earthenware pottery, and promoting local employment.

Potters for Peace, a nongovernmental organization founded by Ron Rivera, redesigned the CWP manufacturing process in the mid-1990s, and promoted filter manufacturing in over 20 countries. CWP filters, now produced at 35 independent factories in 18 countries, are the highest-rated product for rural water treatment (Smart Disinfection Solutions, 2010).

However, each artisanal factory is limited by locally available materials, equipment, and resources. This results in unavoidable variations in production, which occur not only between factories in different countries, but also within each factory.

PATH supports standardization

The primary challenge of standardizing the production process is respecting the art of working with clay, a highly intuitive craft process. Factories adjust production practices according to experience, continually trying to improve their process and end product. The key challenge is maintaining quality control standards in decentralized production facilities.

To assist filter factories in producing the most effective CWP filters possible at the lowest cost, PATH provided funding for members of the Ceramics Manufacturing Working Group (CMWG) to complete a set of best practices and recommendations for the manufacturing of ceramic water filters. The CMWG includes leading CWP experts from international health organizations, universities, and different ceramic filter manufacturing groups.

The resulting set of recommendations, released and distributed worldwide through the CMWG and its members, is available on the Water Institute website: Best Practice Recommendations for Local Manufacturing of Ceramic Pot Filters for Household Water Treatment (2.8 MB PDF).

A better manufacturing approach

CWPs are made by pressing a mixture of clay and a combustible (burn-out) material into the filter shape, allowing it to dry, and then firing it in a kiln. The flow rate of the fired filter is measured for uniformity and colloidal silver is added as a bactericide.

While this seems straightforward, the production process and materials are not standardized among all manufacturers. The CMWG “best practices” include recommendations on factory setup, selection of raw material and processing, employee training, workplace safety, as well as quality control considerations at each step of the production process, including testing and validation.

An ongoing task

While these new recommendations address many of the challenges around standardizing production processes, additional research is needed to further refine these guidelines. PATH and members of the CMWG have also discussed developing standardized training materials and establishing a quality assurance program, including a “seal of approval,” to assist CWP manufacturers. PATH would also like to identify funding to support marketing and business development activities in partnership with CWP factories and the working group.

Photo: PATH.