Tuesday, June 16, 2009

Tornadoes, Hurricanes, Drinking Water and a WAPI

I’ve never lived in Tornado Alley except the year when a tornado leveled Udall, Kansas killing 80 people and injuring hundreds more, about 35 miles from where we lived. However, I grew up in the Land of Hurricanes and have been through perhaps 20 of them from Cat 1’s to Cat 4’s.

So I know only too well the destruction and interruption of services from severe storms. Even now, living in the mountains, hurricanes pose a threat. It’s not the threat of wind damage, but the flooding that brings down mountainsides from rain coming up with a storm from the Gulf of Mexico or coming inland from the Atlantic. 3 inches of rain on relatively flat land isn’t too bad, but 3 inches of rain on a mountain all flows down to the lowest point, becoming feet instead of inches. With any severe storm, the water supply is usually affected.

I have posted how to make an inexpensive emergency water supply apparatus, but that still costs at least $50 for the filter. We all know you can boil water to kill any bacteria in it, but what if you have precious little fuel? Or maybe none? Sooner or later, the sun will come out and with a little cardboard and some aluminum foil you can make a solar oven.

Later this week I will post some plans for making a solar ovens (solar cookers), but solar ovens will not get hot enough to boil water. However, water doesn’t have to reach boiling temps to be safe. Water heated to 149ºF for a short time will pasteurize water; that is, it will kill disease-causing organisms like E. coli, Giardia, Rotaviruses and even the Hepatitis A virus.

Here’s a $6 gadget that you can use with a solar cooker to let you know when the water is pasteurized. It can also be used when heating water over a gas or charcoal grill or even a wood fire. It’s a great addition to camp and emergency packs.

The gadget is actually a simple thermometer called a WAPI, which stands for Water Pasteurization Indicator. It’s a reusable, durable indicator that contains a special soy wax in one end of the tube, and has a moveable weight to keep it at the bottom of the water when in use. When the water (or milk) reaches proper pasteurization temperature, the wax melts and runs to the bottom of the tube. Remove the tube from the pot and let it cool so the wax hardens in the bottom. To re-use, just turn the tube upside down (so the wax is at the top), slide the weight to the bottom, and drop it in cooking water.

WAPI’s are made by Solar Cookers International and sell for $6 (or less in bulk). Churches, Scouts and civic groups often raise money to supply them to Third World countries where millions of people become sick every year from drinking contaminated water. SCI also sells a solar pasteurizer called an AquaPak that is a bag with a WAPI built in. It will pasteurize 4-5 liters in about 2 hours, and sells for $20. Buy 2 and have water for a hot shower!

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