There is a way to disinfect water using only sunlight and plastic bottles. Contaminated water is put into clear plastic bottles and exposed to strong full sun for 6 hours. Placing the bottles on a roof for six hours will do the job.
Guidelines for the application at household level
The ultra-violet radiation of the sun destroys the pathogens in the water.
Solar disinfection is an effective method for treating water where chlorine or boiling the water is not practical. Even where fuel for boiling is available solar disinfection is more economical and environmentally friendly. Reduction of diarrhea cases from solar-treated water is as high as 80%.
International Action has installed more than 100 chlorinators in Port-au-Prince to protect the water of 300,000 people. Each week we are adding more chlorine installations. However, there are 2 million residents of the capital that we have not reached yet.
We have asked our Haitian Director—Dalebrun Esther—to describe on the radio the solar/bottle approach to making safe water. Only small quantities of water can be produced, but Dalebrun speaks on radio in Port-au-Prince reaching an audience of thousands, who have no source of clean water.
Solar disinfection is recommended by the World Health Organization for household water treatment and safe storage. This approach is spreading in many developing countries between latitude 35° N and 35° S.
Suggested Treatment Schedule
| Weather conditions | Minimum Treatment Duration |
|---|---|
| Sunny | 6 hours |
| 50% cloudy | 6 hours |
| 50-100% cloudy | 2 days |
| Continuous rainfall | Unsatisfactory performance, use rainwater harvesting |
“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 causes a serious health hazard and exposes many to the risk of water-borne diseases. There are about 4 billion cases of diarrhea per year, out of which 2.5 million cases end in death, mostly among children under the age of five. This is equivalent to one child dying every 15 seconds or 20 jumbo jets crashing every day. Solar Water Disinfection can contribute to improve this precarious situation.”
Source: www.sodis.ch