News Update
Tests Indicate 99% Removal
of Particles of All Sizes
for the
Ceramiques d'Afrique
Earthenware Water Purifier
Ceramiques d'Afrique to relocate to Bangladesh
Prospects appear excellant for the removal of a high percentage of pathogens during filtration through the Ceramiques d'Afrique earthenware water purifier. While bacteriological tests have yet to be performed, removal of particles of the same sizes as the pathogens would appear to indicate that similar performance can be expected. The goal is effective removal of fecal coliforms, in order to give people in low income areas of the world a chance to get safe drinking water for their families. The purifiers can be readily manufactured on a small scale, and at low cost, within the countries or regions where they are needed.
Previous estimates indicated the need for a silver material, as additional disinfectant, but the the high percentage of pathogens already removed by filtration would appear to make the silver unnecessary. On the other hand, the tiny amount of silver needed is inexpensive, and may still be applied, in order to prevent regrowth of bacteria in the purifier wall. It had been thought that the earthenware purifers would not be capable of more than about 90% removal, thus necessitating the need for the additional disinfectant. But surprisingly, the particle tests, undertaken by a researcher in the U.S., at West Point, New York, have indicated that 99% of particles of all sizes are removed, down to 1.0 micron.
Continued work in perfecting the purifier will continue, following relocation of facilities to Dhaka, Bangladesh at the end of July. Once there, contacts will be established, with the intention of beginning purifier production, as well as training in production. The production phase is to follow the now successful research, undertaken over the past two years.
Ceramiques d'Afrique purifiers have been developed in collaboration with the Nicaraguan based NGO, Potters for Peace.
Purifiers of the type promoted by Potters for Peace are in the form of an earthenware 'filter bucket,' resembling a flower pot and containing 8 liters. For the filter bucket, the filter itself nests in a lower, catchment container. Filter buckets have been proven effective by laboratories in several countries, and are becoming increasingly popular.
By contrast size-wise, the newly developed Ceramiques d'Afrique purifiers are of the 'candle' variety, and are 8 cms. in diameter by 14 cms. high. Wherever the filter candles are produced, their small size and good strength will make it possible to safely ship them without fear of breakage. Workers near the location of the users can fit them into the buckets.
During the past year, simultaneous with research on the earthenware purifier, a second variety of purifier has also been under development, made of a porous concrete. In first purifiers of both types the amount of flow is designed to be an average of 1.0 liter per hour, with a view towards satisfying the drinking water needs of a small
family. At the same time, training modules have been designed, suitable for acquainting would-be producers with the
necessary steps in making the purifiers. In most cases the resources necessary in production are locally available and the startup cost should be very low.
Introducing
Earthenware Purifiers
Earthenware purifiers are formed with the help of a hydraulic, car jack, as shown here in the operation of the press. The primary problem of our research has been to control and improve the amount of flow, beyond what can be expected for conventional earthenware. Part of what makes this possible is a big reduction in the amount of water used during the process of forming the purifiers, from the 35% normal to earthenware down to about 8%. Because of this the clay material resembles a powder, and
several tonnes of pressure are needed when the filters are pressed. A further aid to flow is the
inclusion of a very porous, pre-fired clay material, which can also be made locally.
The silver material used as disinfectant can be applied to the filter in the tiny amounts needed, using either silver nitrate or colloidal silver. When silver nitrate is applied the filters must be fired for a second time, and a combustible must be closed into the kiln with the filters. This results in a reduction atmosphere, which causes the nitrates to be burned off. After running water through the filter several times it is ready for safe use. On the other hand it is possible to apply colloidal silver, without the need for a second firing. Amounts as low as 0.32% silver solution have proven effective in providing potable water.
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Advantages to producers of earthenware purifiers, by comparison to concrete purifiers:
- Filters can be made minutes apart from the same set of dies (ie. molds). In making concrete filters one mold is needed per filter per twenty four hours. So, to make 100 concrete filters per day would require the use of 100 molds.
- The presence of a kiln at the site of production makes possible several other types of product.
