[Stoves] A simple water sterilization technique

Wed Feb 13 19:55:59 CST 2013

Bruce was alluding to the 3M Petrifilms test for E Coli / total coliforms.
I have some experience with these tests and am happy to discuss with folks
who are interested. The cost is around $2 or $3 per test, though 3M has
worked with universities and non-profits to provide free or discounted
tests. I and colleagues have done them in the field and can provide some
experience and advice if desired.

Josh

On Wed, Feb 13, 2013 at 7:00 PM, Bruce Stahlberg <
bruce at affordableenergysolutions.com> wrote:

> Tom, all,
>
> Using the sari to pre-filter the water is a great idea especially where
> the water is particularly dirty before treatment.  If I understand right it
> is a pre-treatment and the water may not be drinkable until treated or at
> least tested to find out if it needs treatment.
>
> The Water Pasteurization Indicator (WAPI) is the lowest of the
> technologies for testing the temperature of water that is offered by Dr.
> Metcalf and others.   For those who want more information about a WAPI:
>
>
> http://www.sunoven.com/products-page/accessories/water-pasteurization-indicator-wapi
>
> Of course, boiling is another, cheaper way to test the temperature.  The
> downside is that it requires more energy than is needed.  The WAPI melts at
> 65 C enough to kill 99% of the bacteria that causes problems for human
> consumption versus 100 C for boiling.  I believe the Peace Corps still
> advises boiling for 20 minutes or at least a period of time.
>
> As can be seen from the link, a WAPI is $9 on the SCI site which is out of
> reach of the populations mostly served by folks on this list.   On the plus
> side, the technology is simple, transportable, can be reused and could be
> made in country if the wax was available.   I am not sure of the
> availability of the wax.
>
> The other techniques are higher up the technology chain.  One is a 3M
> product (which I am not mentioning because I am from Minnesota) and is used
> to test E. Coli here in the states.  There is a cost to each test packet
> and I am not aware of this cost.  The benefit is that it can be tested on
> site without the need for any high tech equipment and does not require any
> electricity, just the temperature of the human body and time.
>
>
> http://solutions.3m.com/wps/portal/3M/en_US/Microbiology/FoodSafety/product-information/product-catalog/?PC_7_RJH9U523003DC023S7P92O3O87000000_nid=C0WJ62882Vbe29BDXSBJ7Fgl
>
> Tom, do you know the availability and cost of these?  I think I saw $2 per
> test plus a small amount for a clean pipet.  Not ideal for families but one
> way to test and confirm water quality in remote areas.
>
> I agree that low tech solutions are the best.  The WAPI can be used in
> conjunction with the sun to know if the water temperature hit the right
> mark.  When the wax is on the bottom it was hot enough.  If not, then the
> water is not safe to drink.
>
> For those of us who have the luxury of clean water at our fingertips I
> appreciate everyone who works on ways to provide clean water to the other
> 90% of the population.  Thanks to you all.
>
> Bruce
>
>
> On Wed, Feb 13, 2013 at 3:47 PM, Jeff Holiman <jeff.holiman at gmail.com>wrote:
>
>> Hello,
>> Dr. Metcalf  continues to mentor Tom Carter, Director of Aqua Pura Para
>> El Pueblo, a group that also works internationally teaching basic water
>> quality testing for coliforms and distributes simple pasteurization
>> indicators made from a wax that melts at 65 C.
>> These indicators have the potential to save much fuel for those folks
>> that are currently boiling water to ensure having reached adequate
>> temperature for pasteurization.
>> Kind regards,
>> Jeff  Holiman
>>
>>
>> On Mon, Feb 11, 2013 at 6:16 AM, Bruce Stahlberg <
>> bruce at affordableenergysolutions.com> wrote:
>>
>>> Greetings,
>>>
>>> Bob Metcalf has been treating and testing water quality in Africa for
>>> many years and uses simple, fairly low tech methods of testing the water on
>>> site to determine if it is safe for drinking.  The testing can be done on
>>> site.  It is explained here:
>>>
>>> www.imageevent.com/bobmetcalf/watertestingpasteurizationinafrica
>>>
>>> Search words:  Bob Metcalf, water pasteurization
>>>
>>> Hope this helps.
>>>
>>> Bruce
>>>
>>> On Fri, Feb 8, 2013 at 6:20 PM, nari phaltan <nariphaltan at gmail.com>wrote:
>>>
>>>> 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
>>>>
>>>>
>>>>
>>>>
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>
>
> --
> Bruce Stahlberg
> Affordable Energy Solutions, Inc.
> 3535 East Lake Street
> Minneapolis, MN  55406
> 612.724.8977
> www.affordableenergysolutions.com
>
>
>
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-- 
Josh Kearns
PhD Candidate, Environmental Engineering
University of Colorado-Boulder
Visiting Researcher, North Carolina State University

Director of Science
Aqueous Solutions
www.aqsolutions.org

Mobile: 720 989 3959
Skype: joshkearns
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