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+ | {{Updated|7|12|17}} |
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⚫ | [[Water pasteurization|Pasteurization]] destroys all microorganisms that cause diseases from drinking contaminated water and milk. A small polycarbonate tube contains a wax that melts when water or milk is heated enough to be pasteurized, i.e., {{Degree|65}}. This saves much fuel by eliminating the need to boil water or milk to ensure that the pasteurization |
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⚫ | [[Image:Wapi-before-after.jpg| |
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− | (65˚C/149˚F). This saves much fuel by eliminating the need to boil water or milk to ensure that the pasteurization |
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temperature has been reached. See also [[WAPI production|Instructions for building WAPIs]]. |
temperature has been reached. See also [[WAPI production|Instructions for building WAPIs]]. |
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Since [[Water pasteurization|water pasteurizes]] at temperatures well below the boiling point of water, WAPIs save time when solar pasteurizing, and save fuel when using traditional fuels. |
Since [[Water pasteurization|water pasteurizes]] at temperatures well below the boiling point of water, WAPIs save time when solar pasteurizing, and save fuel when using traditional fuels. |
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− | {{clr}} |
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+ | Some people have wondered how long the water temperature must be maintained at the pasteurization temperature. The WAPI is designed so that if the wax melts, the water is definitely pasteurized. Also, it should be noted that the water will be slowly rising into the pasteurization zone and then slowly cooling down from the pasteurization temperature. This offers a extra layer of protection since harmful pathogens are being killed even at lower temperatures but at a slower rate. |
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− | *'''May 2007:''' [http://www.knoxnews.com/kns/national/article/0,1406,KNS_350_5551367,00.html Little pieces go long way to provide safe water] - ''Knoxville News Sentinel'' |
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− | == |
+ | =={{HeadingNews}}== |
+ | [[File:North_Star_-Sportswapi2_brochure,_8-8-17.png|thumb|300px|A floating [[WAPI]] from [[North Star Devices]], ''Photo credit: North Star Devices, Inc. 2017]] |
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− | *[http://shop.solarcookers.org/?pn=WAPI&cn=Water+Pasteurization&p=630&c=31 WAPIs can be purchased from Solar Cookers International]. |
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+ | *{{NewAug17}}'''August 2017:''' [[Robert Nepper]] announces that [[North Star Devices]] has created a floating [[water pasteurization]] device known as the SPORTSWAPI 2. |
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+ | *'''February 2014:''' [[Dale Andreatta]], inventor of the [[WAPI]], discusses the latest developments in [[water pasteurization]] at the ETHOS 2013 conference in Kirkland, {{state|Washington}}, [[USA]]. He describes three uses for low temperature (below boiling) solar-heated water, and three simple devices for producing that hot water. In Johnson and Bryden (2012) it is estimated that in a particular village in [[Mali]], 22% of the domestic wood consumption went for water heating exclusive of cooking, while another 52% went for cooking. In a sunny climate the methods presented here would provide most of the energy required for water heating exclusive of cooking, and a substantial fraction of the energy needs for cooking. Read more at: [[Media:Solar Thermal Document.pdf|Solar Thermal Energy for the Village]] - ''Dale Andreatta'' |
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− | * [http://www.sunoven.com Sun Ovens International] sells WAPIs and Solar Ovens |
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− | *The Cool WAPI design does not require heat sealing the tube, but uses a plug to seal the ends instead. See various types, and purchasing information at [[Media:Cool_Wapi_- _Bob_Nepper_January_2013.pdf|The Cool WAPI]] |
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+ | *'''January 2014:''' [[North Star Devices]] announces a sale on the SuperWAPIs. A year-end sale set to end on December 31, 2013, is to be extended until remaining stock is gone. Regularly $225USD for 100 finished units, the price is now $199USD including extended financing options. Read about the WAPI's latest features: [[Media:WaPIFlyer2a.pdf|Reusable Water Pasteurization Indicators (WAPIS)]] |
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− | ==New designs explored== |
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− | [[Image:New_WAPI_designs_1.jpg|left|thumb|113px|End plugs are hammered in, |
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− | eliminating the melting step]] |
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− | The first prototype, from current WAPI makers [[North Star Devices]], is similar in design to current WAPIs in that it is comprised of a wax-filled polycarbonate tube strung with a fishing line and held low in the water with a metal washer. The current WAPI, however, requires that the ends of the tube be melted and pinched - which can be a difficult and slow process - while the new design does not require any heating. Instead, tight-fitting plugs, pre-drilled for fishing line, are hammered in to each end of the tube, sealing in the wax. |
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+ | [[File:Cool_WAPI,_North_Star_Devices,_Inc.,_12-11-13.jpg|thumb|250px|The Cool WAPI from North Star Devices, Inc.]] |
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− | [[Image:New_WAPI_designs_2.jpg|right|thumb|128px|The assembled WAPI, strung with fishing line and washers]]The second prototype was designed by a group of students at Ohio State University (USA) using wax-filled glass capsules from [[Solar Solutions]], makers of the [[AquaPak]] solar pasteurizer. |
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+ | *'''December 2103:''' [[Robert Nepper]] reports that they have made improvements to the SuperWAPI, which features a heat resistant stainless steel cable. North Star Devices' WAPI is the only WAPI offered as a hammer together design, not requiring heat sealing. The SuperWAPI is also now available as a kit. Read more about their WAPIs in their latest flyer: [[Media:WaPIFlyer3.pdf|Reusable Water Pasteurization Indicators (WAPIs)]] |
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+ | *'''November 2013: Study of water treatment in Kenya demonstrates the effectiveness of the WAPI''' - [[Bob Metcalf]], research microbiologist, and [[FOTO]] worked together on a study to compare results of various water treatment chemicals to the [[WAPI]] water pasteurization indicator used with a [[CooKit]] solar cooker. One finding of note is that the WAPI, when used with the CooKit, was 100% effective in producing negative results for E.coli, while the WaterGuard (3 drops/liter) method was only effective in most cases. Read the study at: [[Media:Eliminating Water-bourne Disease Lower Nyakach Kenya 2013.pdf|The Goal is Zero: A Strategy to Eliminate Water-bourne Disease in Lower Nyakach, Kenya]] |
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− | Under the direction of Prof. [[Dennis Guenther]], these students - Arif Mohsin, Zaidi Ahmad Latiffi, Khairil Azim Khairuddin, William Hunter, Shimpei Narita, and Muhammad Yusoff Che-Lah - developed a unique spring and rod system to hold the capsule upright in the water and keep it near the bottom of the pot or jar. The middle seven coils of stainless steel spring, with an inside diameter slightly smaller than the outside diameter of the tube, firmly holds the capsule in place. The three coils on each end of the spring are bent perpendicular to the capsule in such a way that a stainless steel rod can be slid through them with a tight fit. The capsule can then be slid up or down the rod as needed. ''[For further information see [[Media:Improved_WAPI_Final_Report.pdf|Final report on possible improvements to the WAPI]].]'' |
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− | [[Image:Rotary_Youth_Leadership_Awards_youth_Southern_CA_2009.jpg|thumb|300px|Rotary Youth Leadership Awards youth making WAPIs in Southern California for use in projects around the world.]] |
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− | {{clr}} |
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+ | |||
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+ | ==Buying WAPIs== |
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− | The new Cool WAPI, developed by [[Robert Nepper]] and Bill Stevenson, is called “cool” since it requires no heat for assembly when compared to the earlier version WAPI. We have re-designed the WAPI in response to customers who wanted it capable of being assembled in the country of use. We offer it in the completely assembled version and in the totally unassembled version, complete with all parts. |
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+ | *{{NewDec17}}[https://www.sunoven.com/product/water-pasteurization-indicator-wapi/ WAPIs are available from Sun Ovens International] |
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⚫ | *The [http://www.montereysunriserotary.org/wapi.html Monterey Sunrise Rotory Club] sells a kit that contains the materials to make 200 WAPIs. Contact PDG Don Kremer at [mailto:WAPI@pacbell.net WAPI@pacbell.net].* They also sell an embossing tool to use to soften the ends of the plastic tubing when making your own, as an alternative to using an open butane flame. [[North Star Devices]] used to sell WAPI assembly kits and materials. |
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+ | *{{NewJun17}}WAPIs are also [https://www.amazon.com/Sunflair-Water-Pasteurization-Indicator-WAPI/dp/B00F7104EY/ available on Amazon]. |
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− | Yes, unskilled persons can assemble the new cool WAPI with a minimum of tools and instructions. All that is really needed is a common claw hammer and a heavy, flat rock, a cement block or an anvil. It must be solid and heavy or you will find it too difficult to hammer in the plugs. To prevent injured fingers, however, we offer a free simple holder set with initial purchases of 100 pieces or more. The holders also prevent the plugs from being driven in too far (obscuring the holes needed for the fish line). |
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+ | [[File:Superwapi1_medium.jpg|thumb|300px|The new design used plugs to seal the tube and a metal wire that won't melt when used on a cooking fire.]] |
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+ | The Cool WAPI, developed by [[Robert Nepper]] and Bill Stevenson, is called “cool” since it requires no heat for assembly when compared to the earlier version WAPI. According to Robert and Bill: "We have re-designed the WAPI in response to customers who wanted it capable of being assembled in the country of use. We offer it in the completely assembled version and in the totally unassembled version, complete with all parts. Yes, unskilled persons can assemble the new cool WAPI with a minimum of tools and instructions. All that is really needed is a common claw hammer and a heavy, flat rock, a cement block or an anvil. It must be solid and heavy or you will find it too difficult to hammer in the plugs. To prevent injured fingers, however, we offer a free simple holder set with initial purchases of 100 pieces or more. The holders also prevent the plugs from being driven in too far (obscuring the holes needed for the fish line). We sell the completed version for $1.25 each and the unassembled version for $.95 each (in lots of 100 or more). There is quite a bit of manual labor in making the plugs and the wax slug so we cannot offer volume discounts at this time. If the volume gets higher, we will make them with more automation, hopefully to be able to reduce the price and offer volume discounts as well." |
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+ | *See various types at [[Media:Cool Wapi - Bob Nepper January 2013.pdf|The Cool WAPI]]. |
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− | We sell the completed version for $1.25 each and the unassembled version for $.95 each (in lots of 100 or more). There is quite a bit of manual labor in making the plugs and the wax slug so we cannot offer volume discounts at this time. If the volume gets higher, we will make them with more automation, hopefully to be able to reduce the price and offer volume discounts as well. See various types, and purchasing information at [[Media:Cool_Wapi_- _Bob_Nepper_January_2013.pdf|The Cool WAPI]] |
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− | See [[Media: |
+ | *See [[Media:Cool WAPI Assembly Instructions 3-04-09.pdf|Instructions for Assembling the Cool WAPI]]. |
+ | . |
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{{clr}} |
{{clr}} |
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==WAPIs with stainless steel wire== |
==WAPIs with stainless steel wire== |
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− | The [ |
+ | The [http://www.montereysunriserotary.org/wapi.html Monterey Sunrise Rotary Club] now has WAPI kits available in which stainless steel wire replaces the monofilament fishing line; the new WAPI is good for all applications including open flame fires, which had the tendency to melt the traditional fishing line. The kit contans all the components and instructions to build 200 WAPIs. These are reusable and virtually indestructable. The kit costs $85 (about $.42 each) plus shipping. If you are interested in a fun project that teaches about the perils of unclean water and then shows folks how to make a difference, contact us at [mailto:WAPI@pacbell.net WAPI@pacbell.net]. This is a great fellowship project for [[:Category:Rotary Clubs|Rotary Clubs]], Rotary Interact Clubs, Church youth groups, etc. |
==A jig for making WAPIs== |
==A jig for making WAPIs== |
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==Audio and video== |
==Audio and video== |
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+ | *{{NewMar17}}'''January 2017:''' |
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− | <youtube>rKsVcB_07iI</youtube> |
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+ | ::[[File:Dr. Akihiko Kumagai - What Would be a Sustainable WAPI Producing Method for Developing Countries?|none|400px]] |
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+ | *{{NewApr17}}'''April 2014''' |
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⚫ | |||
+ | ::[[File:WAPI - Water Pasteurization Indicator|none|400 px]] |
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+ | *'''March 2010:''' |
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+ | |||
+ | *'''February 2008:''' |
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+ | ::[[File:Tusk Trust Documentary - 07 Making Water Safe to Drink|thumb|none|400px|Making Water Safe to Drink with the [[WAPI]].]] |
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+ | |||
+ | *'''September 2007:''' |
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+ | ::[[File:Water Pasteurization Indicator (WAPI)|400px|none]] |
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+ | |||
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+ | The method described below is included to spark innovation and hasn't been tested for possible chemical contamination from the hot glue. |
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[[File:Soda_straw_WAPI.jpg|thumb|none|300px|'''Straw Pasteurizer Indicator''' - (see above) A disposable pasteurizer indicator invented by [mailto:larnedmarlow@gmail.com Eric Marlow] that can be made by taking a plastic soda straw and folding it back on itself and applying hot glue. [[Media:Soda bottle pasteurizer Eric Marlow - 2010.pdf|More information...]]]] |
[[File:Soda_straw_WAPI.jpg|thumb|none|300px|'''Straw Pasteurizer Indicator''' - (see above) A disposable pasteurizer indicator invented by [mailto:larnedmarlow@gmail.com Eric Marlow] that can be made by taking a plastic soda straw and folding it back on itself and applying hot glue. [[Media:Soda bottle pasteurizer Eric Marlow - 2010.pdf|More information...]]]] |
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+ | |||
+ | ==Reports== |
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+ | *{{NewMar17}}'''January 2017:''' [[Media:What would be a Sustainable Water Pasteurization Indicator (WAPI) Producing Method for Developing Countries Kumagai.pdf|What Would be a Sustainable Water Pasteurization Indicator (WAPI) Producing Method for Developing Countries?]] [http://solarcooking.org/conferences/WAPI_Production_Method_for_Developing_Countries_Kumagai_slides.pdf (slides)] - ''Akihiko Kumagai'' |
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==See also== |
==See also== |
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− | *WAPI instructions in [[Media: |
+ | *WAPI instructions in [[Media:WAPI instructions English.pdf|English]], [[Media:WAPI Instructions Spanish.pdf|Spanish]], and [[Media:Wapi directions (portuguese).pdf|Portuguese]] |
+ | *The [[Boil 3, Add 1 Method]] allows for the fuel savings of pasteurization (versus sterilization) without the need for a temperature measuring device. |
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+ | *[[Media:Eliminating Water-bourne Disease Lower Nyakach Kenya 2013.pdf|The Goal is Zero: A Strategy to Eliminate Water-bourne Disease in Lower Nyakach, Kenya, 2013]] - ''[[Bob Metcalf]] and [[FOTO]]'' |
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*[[WAPI production]] |
*[[WAPI production]] |
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+ | *{{NewJul17}}[[International shipping]] |
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*[[SPADE WAPI]] |
*[[SPADE WAPI]] |
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*[[Bob Metcalf]] |
*[[Bob Metcalf]] |
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*[[Portable Microbiology Laboratory]] |
*[[Portable Microbiology Laboratory]] |
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*[[Integrated Cooking Method]] |
*[[Integrated Cooking Method]] |
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− | *[[Media: |
+ | *[[Media:Improved WAPI Final Report.pdf|Report on possible improvements to the WAPI]] |
+ | *[[Research topics]] |
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− | *[[Topics needing research]] |
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==External links== |
==External links== |
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+ | |||
− | *[http://shop.solarcookers.org/?pn=WAPI&cn=Water+Pasteurization&p=630&c=31 WAPIs can be purchased from Solar Cookers International]. |
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*[http://solarcooking.org/phpBB2/viewtopic.php?p=82 Making a WAPI from a ballpoint pen] |
*[http://solarcooking.org/phpBB2/viewtopic.php?p=82 Making a WAPI from a ballpoint pen] |
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[[Category:WAPI devices]] |
[[Category:WAPI devices]] |
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[[Category:Health and safety]] |
[[Category:Health and safety]] |
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[[Category:Water pasteurization]] |
[[Category:Water pasteurization]] |
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+ | [[Category:Materials]] |
Latest revision as of 18:25, 30 June 2023
Last edited: 12 July 2017
|
The Water Pasteurization Indicator (WAPI) is a simple indicator that shows water has reached pasteurization temperature and is safe to drink. It was invented by Fred Barrett and Dale Andreatta.
Pasteurization destroys all microorganisms that cause diseases from drinking contaminated water and milk. A small polycarbonate tube contains a wax that melts when water or milk is heated enough to be pasteurized, i.e., 65 °C (149 °F). This saves much fuel by eliminating the need to boil water or milk to ensure that the pasteurization temperature has been reached. See also Instructions for building WAPIs.
Since water pasteurizes at temperatures well below the boiling point of water, WAPIs save time when solar pasteurizing, and save fuel when using traditional fuels.
Some people have wondered how long the water temperature must be maintained at the pasteurization temperature. The WAPI is designed so that if the wax melts, the water is definitely pasteurized. Also, it should be noted that the water will be slowly rising into the pasteurization zone and then slowly cooling down from the pasteurization temperature. This offers a extra layer of protection since harmful pathogens are being killed even at lower temperatures but at a slower rate.
News[]
- August 2017: Robert Nepper announces that North Star Devices has created a floating water pasteurization device known as the SPORTSWAPI 2.
- February 2014: Dale Andreatta, inventor of the WAPI, discusses the latest developments in water pasteurization at the ETHOS 2013 conference in Kirkland, Washington, USA. He describes three uses for low temperature (below boiling) solar-heated water, and three simple devices for producing that hot water. In Johnson and Bryden (2012) it is estimated that in a particular village in Mali, 22% of the domestic wood consumption went for water heating exclusive of cooking, while another 52% went for cooking. In a sunny climate the methods presented here would provide most of the energy required for water heating exclusive of cooking, and a substantial fraction of the energy needs for cooking. Read more at: Solar Thermal Energy for the Village - Dale Andreatta
- January 2014: North Star Devices announces a sale on the SuperWAPIs. A year-end sale set to end on December 31, 2013, is to be extended until remaining stock is gone. Regularly $225USD for 100 finished units, the price is now $199USD including extended financing options. Read about the WAPI's latest features: Reusable Water Pasteurization Indicators (WAPIS)
- December 2103: Robert Nepper reports that they have made improvements to the SuperWAPI, which features a heat resistant stainless steel cable. North Star Devices' WAPI is the only WAPI offered as a hammer together design, not requiring heat sealing. The SuperWAPI is also now available as a kit. Read more about their WAPIs in their latest flyer: Reusable Water Pasteurization Indicators (WAPIs)
- November 2013: Study of water treatment in Kenya demonstrates the effectiveness of the WAPI - Bob Metcalf, research microbiologist, and FOTO worked together on a study to compare results of various water treatment chemicals to the WAPI water pasteurization indicator used with a CooKit solar cooker. One finding of note is that the WAPI, when used with the CooKit, was 100% effective in producing negative results for E.coli, while the WaterGuard (3 drops/liter) method was only effective in most cases. Read the study at: The Goal is Zero: A Strategy to Eliminate Water-bourne Disease in Lower Nyakach, Kenya
Articles in the media[]
- January 2010: WAPIs set to go to Haiti - Recorder Online
- December 2003: Professor sees solar solution to safer water - Sacramento State News
Buying WAPIs[]
- WAPIs are available from Sun Ovens International
- The Monterey Sunrise Rotory Club sells a kit that contains the materials to make 200 WAPIs. Contact PDG Don Kremer at WAPI@pacbell.net.* They also sell an embossing tool to use to soften the ends of the plastic tubing when making your own, as an alternative to using an open butane flame. North Star Devices used to sell WAPI assembly kits and materials.
- WAPIs are also available on Amazon.
Improved design: The Cool WAPI[]
The Cool WAPI, developed by Robert Nepper and Bill Stevenson, is called “cool” since it requires no heat for assembly when compared to the earlier version WAPI. According to Robert and Bill: "We have re-designed the WAPI in response to customers who wanted it capable of being assembled in the country of use. We offer it in the completely assembled version and in the totally unassembled version, complete with all parts. Yes, unskilled persons can assemble the new cool WAPI with a minimum of tools and instructions. All that is really needed is a common claw hammer and a heavy, flat rock, a cement block or an anvil. It must be solid and heavy or you will find it too difficult to hammer in the plugs. To prevent injured fingers, however, we offer a free simple holder set with initial purchases of 100 pieces or more. The holders also prevent the plugs from being driven in too far (obscuring the holes needed for the fish line). We sell the completed version for $1.25 each and the unassembled version for $.95 each (in lots of 100 or more). There is quite a bit of manual labor in making the plugs and the wax slug so we cannot offer volume discounts at this time. If the volume gets higher, we will make them with more automation, hopefully to be able to reduce the price and offer volume discounts as well."
- See various types at The Cool WAPI.
.
WAPIs with stainless steel wire[]
The Monterey Sunrise Rotary Club now has WAPI kits available in which stainless steel wire replaces the monofilament fishing line; the new WAPI is good for all applications including open flame fires, which had the tendency to melt the traditional fishing line. The kit contans all the components and instructions to build 200 WAPIs. These are reusable and virtually indestructable. The kit costs $85 (about $.42 each) plus shipping. If you are interested in a fun project that teaches about the perils of unclean water and then shows folks how to make a difference, contact us at WAPI@pacbell.net. This is a great fellowship project for Rotary Clubs, Rotary Interact Clubs, Church youth groups, etc.
A jig for making WAPIs[]
The SPADE WAPI for bottles[]
Another technique that has developed from seeking a simple solution to water pasteurization is the SODIS approach. Basically it involves leaving sealed transparent bottles of clear, but untreated, water in direct sunshine from two to four hours. The time will depend on the surfaces below the bottles, and the intensity of the sunshine. Often the bottles are placed on a flat corrugated metal roof. When the water reaches 65°C(150°F) it is suitable for drinking. As mentioned earlier, a need developed to find a simple device, a WAPI, to indicate when the water was safe. Several designs use a melting wax method. A recent version, called the SPADE WAPI, is designed to be fitted directly to the cap on a water bottle. After drilling a 1/4" hole through the cap. The slender clear tube, with wax at one end, is submerged into the bottle. Reaching a safe temperature, the wax runs to the bottom of the tube. A compact approach to providing water pasteurization using existing bottles.
Audio and video[]
- January 2017:
- April 2014
- March 2010:
- February 2008:
- September 2007:
Disposible soda straw variation[]
The method described below is included to spark innovation and hasn't been tested for possible chemical contamination from the hot glue.
Reports[]
- January 2017: What Would be a Sustainable Water Pasteurization Indicator (WAPI) Producing Method for Developing Countries? (slides) - Akihiko Kumagai
See also[]
- WAPI instructions in English, Spanish, and Portuguese
- The Boil 3, Add 1 Method allows for the fuel savings of pasteurization (versus sterilization) without the need for a temperature measuring device.
- The Goal is Zero: A Strategy to Eliminate Water-bourne Disease in Lower Nyakach, Kenya, 2013 - Bob Metcalf and FOTO
- WAPI production
- International shipping
- SPADE WAPI
- Bob Metcalf
- Water pasteurization
- Portable Microbiology Laboratory
- Integrated Cooking Method
- Report on possible improvements to the WAPI
- Research topics