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Solar Disinfection System
In 1991, a group of scientists and engineers in Switzerland tried to
use everyday tools to make drinking water safe. They wanted to find a
way to get rid of disease-causing bacteria without expensive chemical
treatment.
The solution was a solar disinfection system, or SODIS. It relies on
a few simple items and sunshine. SODIS works best in countries near
the equator. That’s where sunshine is strongest.
Here’s how SODIS works.
1.
Get a clean, clear plastic bottle with a cap. (Glass can be used,
but clear plastic is best.)
2.
Fill the bottle with water and put the cap on.
3.
Lay the bottle flat on a piece of corrugated tin or on a roof.
4.
Let the bottle lie in the sunshine for 6 hours to 2 days,
depending on how cloudy it is. Then the water is ready to drink.
Light from the Sun is called
solar radiation
. The ultraviolet part
of solar radiation kills bad bacteria and makes it safe to drink. Heat
and ultraviolet radiation from the Sun work together to disinfect the
water.
What’s so great about SODIS? It costs nothing at all, and it recycles
plastic bottles. Sometimes the simplest solutions are the best.
1
Clean the bottles.
2
Fill the bottles
with water.
3
Put the bottles
in sunshine.
4
Wait 6 hours to 2 days.
5
Drink the safe water.
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