Using the Sun to Sterilize Your Drinking Water.

Forget expensive chlorination – Tanzanian villagers used free sunlight to sterilize their water.

"I fill the plastic bottles, put the lids on, then put them on my black-painted roof where they stay for a whole day."

The sun heats the water, helped by the black roof, which helps to absorb the heat.

Solar radiation means a combination of ultra-violet rays and heat destroys the bacteria which cause common water-borne diseases like cholera, typhoid, dysentery and diahorrea.

After eight hours in the sun, it is ready to drink.

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