[Stoves] A simple water sterilization technique

[Bruce Stahlberg]

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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