Cactus gum could make clean water cheap for millions

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Buckethead
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Cactus gum could make clean water cheap for millions

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http://www.newscientist.com/article/mg2 ... lions.html

* 27 April 2010 by Helen Knight
* Magazine issue 2757. Subscribe and save
* For similar stories, visit the Food and Drink Topic Guide

FORGET expensive machinery, the best way to purify water could be hiding in a cactus. It turns out that an extract from the prickly pear cactus is effective at removing sediment and bacteria from dirty water.

Many water purification methods introduced into the developing world are quickly abandoned as people don't know how to use and maintain them, says Norma Alcantar at the University of South Florida in Tampa. So she and her colleagues decided to investigate the prickly pear cactus, Opuntia ficus-indica, which 19th-century Mexican communities used as a water purifier. The cactus is found across the globe.

The team extracted the cactus's mucilage - the thick gum the plant uses to store water. They then mixed this with water to which they had added high levels of either sediment or the bacterium Bacillus cereus.

Alcantar found that the mucilage acted as a flocculant, causing the sediment particles to join together and settle to the bottom of the water samples. The gum also caused the bacteria to combine and settle, allowing 98 per cent of bacteria to be filtered from the water (Environmental Science and Technology, DOI: 10.1021/es9030744). They now intend to test it on natural water.

Householders in the developing world could boil a slice of cactus to release the mucilage and add it to water in need of purification, says Alcantar. "The cactus's prevalence, affordability and cultural acceptance make it an attractive natural material for water purification technologies."

But Colin Horwitz of GreenOx Catalysts in Pittsburgh, Pennsylvania, says many issues remain, including how much land and water is needed to grow cacti for widespread water purification, and how households will know all the bacteria have been removed.
daiv
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Post by daiv »

Good old O. ficus-indica is probably the most useful species already.
All Cacti are succulents, but not all succulents are Cacti
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Arzberger
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Post by Arzberger »

Very interesting!
I imagine, that this would be specifically useful for our very dry chaco, where people have to deal with stored rainwater and its impurity.
Thanks for sharing the info!

Regards
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Peterthecactusguy
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Post by Peterthecactusguy »

I could also see how it might help people in places that don't have any water to waste at all. In other words if it gets dirt in it and they don't have any more water throw some of the Opuntia stuff into the water and bingo fresh water.

Interesting thanks for sharing.
btw it's interesting all the things that O. ficus-indica is good for! :)
Here's to you, all you insidious creatures of green..er I mean cacti.
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Post by Loph »

very cool. maybe not good enough for "the developed world", but the other 90% of people could probably sure benefit from it! 98% is pretty darn fantastic for such a simple method.
Stephen Robert Irwin: 22 February 1962 – 4 September 2006. Rest In Peace.
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