This ‘One World’ task is about the Lifestraw, a water purifier for developing countries. It is aimed at middle school students.
Slideshow about water sources, use and purification Water sources.
AraBern sewerage treatment plant in Berne http://www.ara-bern.ch/.
The student sheets can be accessed here: Lifestraw student sheet Lifestraw Simplified student sheet.
Lifestraw Movie 2min30s
“Lifestraw from Vestergaard Frandsen.” youtube. 11 Nov 2008. Web. 8 Dec 2009.
<http://www.youtube.com/watch?v=e6B65Z10BKE>
LifeStraw – FAQ
What is LifeStraw?
LifeStraw is a portable water purifier that removes all bacteria and viruses responsible for causing common diarrhoea. LifeStraw needs no electrical power or spare parts and can be carried around for easy access to safe and clean water.
What is the need for LifeStraw?
Many kids who walk long distances to and from school, find it difficult to obtain clean drinking water. LifeStraw has been developed to provide a solution to the ‘instant’ need for safe water.
Who can use LifeStraw?
Since humans have the natural ability to suck, both adults and children above three years can use LifeStraw.
What is the shelf life of LifeStraw?
LifeStraw can be stored for three years at a maximum temperature of 30 degrees. Storage at a higher temperature will not stop the working of LifeStraw but the first few millilitres of water consumed will have an initial lower killing effect on the bacteria and viruses.
What effect does LifeStraw have on salt water?
LifeStraw does not make salt water drinkable; but it still removes the bacteria and viruses from the salty water.
Does LifeStraw filter dissolved heavy metals like arsenic, iron and fluoride?
No, the present version does not filter any of the heavy metals.
Does LifeStraw remove parasites like cryptosporidium and giardia?
No, the present version does not filter any parasites.
adapted from “Lifestraw FAQ.” Vestergaard Frandsen. 2009. Web. 8 Dec 2009. <http://www.vestergaard-frandsen.com/lifestraw.htm>
Lifestraw
LifeStraw is a water filter designed by the Swiss-based Vestergaard Frandsen for people living in developing nations. The LifeStraw filters a minimum of 700 litres of water, enough for one person for one year. The LifeStraw kills 99.9999% of waterborne bacteria and 98.5% of viruses. The LifeStraw is a plastic tube 31cm long and 3cm in diameter. It costs around $5.00.
Water that is sucked through the straw first passes through a filter with 0.1mm spaces, then through a filter with 0.015mm spaces. Water then passes through a chamber with balls inside, which are coated in iodine to kill bacteria which are not caught in the filter. The process is powered by a person sucking, similar to using a conventional drinking straw.
LifeStraw Personal has been praised for its effective and instant method of bacteria removal. The filter does not currently remove the parasite Giardia lamblia, but the company is working on this issue.
The device also causes higher-than-normal iodine levels in the drinkers’ water, although this is countered by the iodine deficiency problem that exists in the third world.
Paul Hetherington, of the charity WaterAid, has criticised the LifeStraw Personal for being too expensive for people in low income countries. He also said there were other important problems with accessing clean water in developing countries, which are not solved by the Lifestraw.
adapted from “Lifestraw.” wikipedia.org. Wikipedia, 16 Nov 2009. Web. 8 Dec 2009. <http://en.wikipedia.org/wiki/LifeStraw>
One World Science 