[Stoves] A simple water sterilization technique

Tue Feb 12 15:08:02 CST 2013

Greetings Charlie and  Bruce, 
That is a  great move forward you have both made in the field detection of the key bacteriologic contaminants in drinking water .  I hope that the grand finale of your efforts would be to identify local materials resources  that can be adapted to your tests, so that it can become a fully locally owned process: Charlie, you seem closer to that goal in using sari cloth but what about indicators in the surrounding plant & animal community ; What in  that environment indicates the presence of  ecoli and how can it be calibrated to your analytical assessment.  

(As an example of what i am suggesting, towards the end of our 5 year contract with the Swedish aid in Tanzania in the late 70's, we used dead cow bones crushed and heated to actively exchange the  flouride ion from otherwise unpotable flouride rich drinking water that flowed ot of contact springs all around the side to the proximate Mt Meru.   (This idea was developed by a nameless Arizona rancher that if the water was turning his ranch hands' teeth brown and making their children bowlegged, then  why not feed the water thru said cow bones first. He allegedly heated the bones to make them more brittle and make them more attractive for the simle ion exchange required,  then smashed them into crumbs with a small sledge hammer and dumped  them into an 1 gal coffee tin and dripped the flouride water through it. the resulting water was relatively free of flouride , the crushed bones turned brown indicating definate exchange of ions, taking place . He would then dump out the  bones when they "turned brown" refilling the tin with a new batch and so on. The "when it turns brown" was is the interesting part.  I had planned to  calibrate  what "turning brown" meant with my trusty hatch kit to get some idea of what that indicated for testing purposes but never got the chance to do so. The users on Mt meet simply went by color indicators but thus a solution was born.  

For us at least,  all about local ownership of the process when and where possible right down to the ground and the resources they have available again where possible.. Just wondering if it might be possible to push the envelope a bit farther to better assure complete local adaptation. 
Either way it was good  to learn that someone is moving in the right direction. Keep up the good work !

Richard Stanley
www.legacyfound.org

On Feb 10, 2013, at 11:30 PM, Charlie Sellers wrote:

Thank you for that great reference on improved investigations into this simple approach!  We looked into the use of sari cloth filtration when we explored methods to use when constructing slow sand filters for an EWB project, where we needed to effectively sieve the media so that it had the right particle size distribution.  The information we had available to us concerned just mechanical filtration aspects:
http://www.nytimes.com/2011/09/27/health/27sari.html?_r=0
and as a materials scientist I especially liked their electron microscope images, showing the differences between new and used sari materials (showing openings on the order of ~20 microns):
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC298724/?tool=pmcentrez

But the bottom line is that locally available materials/methods worked for them in Bangladesh, and now the addition of heating the water afterwards can lead to even further improvements in the approach's efficacy.

From: nari phaltan <nariphaltan at gmail.com>
To: Discussion of biomass cooking stoves <stoves at lists.bioenergylists.org> 
Sent: Friday, February 8, 2013 4:20 PM
Subject: [Stoves] A simple water sterilization technique

Hello stovers,

One of the major problems of rural areas is unavailability of clean drinking water. A simple method of filtration and heating it to 55-60 degrees Celsius can remove all bacteria. The paper is at; http://www.currentscience.ac.in/php/forthcoming/RC494.pdf

And the news item is at; http://www.firstpost.com/fwire/sari-sun-combo-can-sterilise-dirty-water-619304.html?utm_source=fwire&utm_medium=hp

Cheers.

Anil

-- 
Nimbkar Agricultural Research Institute (NARI)
Tambmal, Phaltan-Lonand Road
P.O.Box 44
Phaltan-415523, Maharashtra, India
Ph:91-2166-222396/220945
e-mail:nariphaltan at gmail.com
          anilrajvanshi at gmail.com

http://www.nariphaltan.org

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