SODIS WATER TREATMENT
This Section Contains:
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Field Notes
SODIS WATER TREATMENT: FIELD NOTES
At least one third of the population in developing countries has no access to safe drinking water. The lack of adequate water supply and sanitation facilities exposes many to the risk of water-borne diseases. There are about 1.8 million cases of diarrhea each year which end in death. Every day about 4000 children die of dehydration due to diarrhea.
SODIS, Solar Water Disinfection, improves the microbiological quality of drinking water, using both solar UV-A radiation and temperature to inactivate pathogens causing diarrhea.
The SODIS system works in the following way:
When the direct sun rays, and especially the ultraviolet radiation present in them, penetrate water in clear plastic bottles, they completely destroy the human pathogens. The sunlight also increases the water temperature, which contributes to killing the microbes. This disinfected water is suitable for human consumption.
Human pathogens present in the water are very sensitive to solar radiation because they normally live in our stomachs and intestines. They therefore do not have any protective mechanisms against sunlight.
Fill two-liter, clear plastic bottles completely with water. The bottles can be exposed lying horizontally to the sun on the metal roof of a house. It is important that they receive sun during at least 6 hours of the day - from at least 9 o’clock in the morning until 3 o’clock in the afternoon.
It is recommended to use twice the number of SODIS bottles that you require for daily drinking water. While one bottle is being exposed to the sun, the other bottle is available for drinking. The SODIS bottle is a clean and safe container, protecting the water against recontamination; store the disinfected water in the SODIS bottle itself and not in a different container which could be contaminated.
Useful Links:
SODIS: http://www.sodis.ch/
Adapted from: Solar Water Disinfection; A guide for the Application of SODIS
