This is a update of an article that I posted several years ago on how to pasteurize your water. It explains how you can pasteurize your water without bringing it to a boil. In an emergency this little device can save you fuel by shorting the time in which you have to heat your water. It is inexpensive, reliable and can be reused indefinitely. research indicates that it has proved effective in third world countries.
Because of its low price $7.00 you can afford to purchase several. It is small and will store almost anywhere. The downside to it is that it does take a heat source to work and it will not remove chemicals or other contaminates.
I have often felt after talking with people that water purification is a major weakness that many of us share. In my family, we have the capability to treat large amounts of water. We have several good-quality gravity filters and numerous smaller units.
But with all of that, we still have an ace in the hole. The WAPI stands for Water Pasteurization Indicator
This new method of water purification using the solar ovens and the sun has been developed by Dr. Bob Metcalf, a professor in microbiology at California State University at Sacramento.
Water Pasteurization Indicator (WAPI) is a simple thermometer that indicates when water has reached pasteurization temperature and is safe to consume. Pasteurization destroys all microorganisms that cause diseases from drinking contaminated water. The WAPI consists of a small polycarbonate tube that contains a soy wax that melts when water is heated enough to be pasteurized (65˚C/149˚F). Heating water to 149˚F kills E. coli, rotaviruses, giardia, and the hepatitis A virus. It is my understanding that the wax melts at 160° F.
Instruction on how to use a WAPI – The WAPI can be used in stoves heated with most fuels, including wood, gas, kerosene, charcoal, but it was originally designed to work with solar ovens.
Fill your container (do not use plastic) with water, place over heat or in a solar oven. Place WAPI in water with the wax-filled end up. To do this you have to slide the weigh so that it is on the opposite end from the wax.
This puts the wax end nearest the surface of the water. When the water reaches the correct temperature, the wax melts and falls to the bottom of the WAPI. This shows that the water has been pasteurized and is ready to drink.
Remember pasteurization does not remove dangerous chemicals. Pasteurization is not the same as sterilization and the WAPI should not be used for medical or food canning.
The WAPI can be purchased at Solar Cookers International for $7.00. This has to be an all-time bargain for a water purification device that will last for many years and requires no maintenance or filters..