Prize winner, Julie Frost, from the University of New South Wales in Sydney, Australia, developed a cleverly shaped plastic bucket with a dark polyethylene lining, that ladies in developing countries can fill at a well and then balance on the heads to transport home as they've traditionally done.

To date, nothing has changed. But once the precious water arrives home in Julie's bucket, that she calls a mvura (Shona for 'water'), the changes come thick and fast. easy pure water purifier price in bangladesh

First, the woman places the bucket on the floor and it opens right into a flat lotus flower shape. Amazing! The flexible black polythene lining spreads out, still holding every one of its 15 liters of water, so nothing is spilled. That is then put into the hot African sun ... and Julie's magic begins in this ingenious home made water purifier.

In just two hours the heat of the sun, amplified by the black plastic, heats the water to 65 degrees. The village water carrier knows when this temperature has been reached because some simple soybean wax could have melted. And when that has happened the water becomes pasteurized and harmful bacteria is likely to be neutralized.