Difference between revisions of "Ceramic candle filter"

Revision as of 11:03, 15 July 2010

Diagram of a ceramic candle filter

Man using the ceramic candle filter

There are several producers of ceramic candle filters. The product discussed here is the Water4life Gravity Unit ceramic candle filter.

The system consists of two reservoirs on top of each other. The top reservoir contains at least one candle and at most two filter candles. The lower bucket works as safe storage for treated water. The top reservoir is filled with contaminated source water. Gravity pushes the water gradually through the porous filter candle. The average flow rate of the water is limited to about 1 to 2 litres per hour.

The filter candles are from India, China, Indonesia or Brazil. Layer 1 is made from clay which is fired to attain a fine pore structure. The size of these pores differ. But the Brazil Stefani candles can stop any particles / bacteria larger than 0,5 micrometer. The second layer is impregnated with colloidal silver on the inside and outside which deactivates bacteria. In layer 3, it is filled up with activated carbon. This is a material that has huge potential to adsorb. Contaminants slide into the holes of this honeycomb and hold fast. thereby it can hold iron, chlorine, odour and colour.

History and social context

Suitable conditions

Technical specification

Operation

When new candles are used, don’t consume the first 5 litres for drinking water. Do not clean the unit and candles every day. Filter candles need to be cleaned when flow rate is very low. Use some water an a piece of cloth to rub the dirt off the candles. Never use soap or other detergents. If the dirt has penetrated the outer layers of the ceramics, scrapping off the outer layer is needed. This can be done by using hard brush. Take care that no crack is introduced. Once a crack is created the water is no longer safe.

Store clean water covered and away from sunlight. To prevent recontamination, refrain from opening the lower vessel for any reason and access the filtered water only through the tap.

Complete user’s directions are provided when unit is purchased. Motivational campaigns, extensive training or other instructions could optimize health benefits, reduce failures, and improve the longevity and sustainability of the intervention

Maintenance

The design of steel vessels are very robust. As long as proper O&M is conducted, no real damage should occur. However, candles need to be handled more cautiously especially during maintenance.

Manufacturing

Local entrepreneur Water4Life Field testing in 17 villages throughout the Mpongwe District, Zambia in 2009; commissioned by Water4Lifes. Six months intervention study in a rural community near Cochabamba, Bolivia in 2003 [2].

Local manufacturer or local trading group is supported by Water4life.

Estimated Lifespan

The need of replacing the candle filter is mainly due to clogging. One candle could normally produce 7.000 litres of water.

As for the steel vessels, they will easily last 10 years.

Cost

[a] based on the Water4life filter; include production cost, training and education of users and manufacturers .[b] based on the filter system used in Charinco. Assuming daily usage of 25 litres/system. [c] price in India with 1 nanosilver candle [d] metal design water purifier with one candle [e] plastic water purifier consists of two plastic buckets that cost €1 each, a tap costs €0,30 and one candle. For all filters, extra carbon cartridge cost €1,30

Country experiences

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Acknowledgements

This article is based on a factsheet from Aqua For All…..

References

• http://www.solarsolutions.info/main.html

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