[Stoves] A simple water sterilization technique

Wed Feb 13 21:47:40 CST 2013

Thanks for an interesting discussion. I am again putting the story on our
work in case it was missed.
http://news.in.msn.com/national/article.aspx?cp-documentid=252177469

Most of the women in rural areas in our part of India heat water for bath.
The away to know that water has been heated is by putting hand in the
water. At 60 degrees celsius one can hardly keep the hand for 4-5 seconds
in water. This is a good indicator of temperature. Thus filtering dirty
water through 4 layers of sari and then heating to 60 degrees Celsius is
safe for drinking purposes.

The full paper is at; www.nariphaltan.org/watersterilizaion.pdf

Cheers.

Anil

On Thu, Feb 14, 2013 at 8:53 AM, Bruce Stahlberg <
bruce at affordableenergysolutions.com> wrote:

> Agreed.  This is the price on the internet from SCI.  They typically use
> the funds to help out with projects elsewhere.  Especially in bulk the
> price per unit would be much less.  Does anyone have any experience of
> making them?
>
> Bruce
>
> On Wed, Feb 13, 2013 at 8:45 PM, Crispin Pemberton-Pigott <
> crispinpigott at gmail.com> wrote:
>
>> Dear Bruce, Tom and All****
>>
>> ** **
>>
>> I recall the pasteurization indicator being pitched to our Rotary Club in
>> Swaziland and it was much less than $9 so I suspect it is an ‘advertised’
>> or ‘list’ price. There must be a bulk price as well.  ****
>>
>> ** **
>>
>> Regards****
>>
>> Crispin****
>>
>> ** **
>>
>> ++++
>>
>> 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
>>
>> ****
>>
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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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-- 
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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