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 <[email protected]>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 < > [email protected]> 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 <[email protected]>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 >>> >>> >>> >>> > _______________________________________________ > Stoves mailing list > > to Send a Message to the list, use the email address > [email protected] > > to UNSUBSCRIBE or Change your List Settings use the web page > > http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org > > for more Biomass Cooking Stoves, News and Information see our web site: > http://www.bioenergylists.org/ > > > -- Bruce Stahlberg Affordable Energy Solutions, Inc. 3535 East Lake Street Minneapolis, MN 55406 612.724.8977 www.affordableenergysolutions.com
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