[Stoves] A simple water sterilization technique

[Crispin Pemberton-Pigott]

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-indica
tor-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=C0WJ6
2882Vbe29BDXSBJ7Fgl 

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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