Quick Answer
You can safely purify water using sunlight during desert nights, but only if the water is left in a clear container and placed in direct sunlight for a sufficient amount of time.
Using Solar Disinfection for Water Purification
To purify water using sunlight, you’ll need to employ the solar disinfection (SODIS) method. This involves filling a clear plastic bottle or container with the water you want to purify and then leaving it in direct sunlight for at least six hours. The UV rays in the sunlight will kill bacteria, viruses, and other microorganisms that can cause illness.
Calculating the Right Amount of Time
The length of time required for SODIS to be effective depends on several factors, including the type of container used, the amount of water, and the intensity of the sunlight. Generally, a clear plastic bottle left in direct sunlight will require at least six hours to kill most bacteria and viruses. However, the Centers for Disease Control and Prevention (CDC) recommend leaving the water in the sun for at least 6 hours, or the entire day if possible.
Important Considerations for Desert Travel
When using SODIS for water purification in a desert environment, it’s essential to take into account the night’s low temperature and the potential for dew or frost to form on the container. In temperatures below 40°F (4°C), SODIS may not be effective, and you may need to use alternative methods for water purification. Additionally, if the water is cloudy or contains particulate matter, it may not be suitable for SODIS.
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