EMERGENCY DISINFECTION OF WATER

There are times when access to disinfected water is not available and expedient methods must be employed. Some people will be caught off guard, while others will be en route in an evacuation and need potable water. These methods are for small volumes of water, rather than large volumes stored in a sterilized container in a fixed location.

There are variations on this theme, however. Emergency disinfection may be required for larger volumes of water for those using a motor home or travel trailer during an evacuation. In every case, the water to be used should be as clean as possible prior to disinfection. Steam or pond water may be found in a place of relative safety, for example, so the large water holding tank can be filled. One slow but sure method is to pass all water through a fine grade nylon paint filter in a 5 gallon bucket which has been fitted with a hose bib at the bottom for drainage, to remove large debris, then through a nylon permanent style coffee filter placed over a funnel, and then into the tank. The water can then be disinfected with the proper amount of chlorine product, and be safe to drink in a half hour.

Small quantities of water may be disinfected to destroy harmful bacteria by one of the following methods:

BOILING

Boil the water briskly for five minutes. Allow the water to cool and store in a sterile, covered container. If the taste is flat, pour the water back and forth from one clean container to another to allow air to be absorbed. This is the safest and simplest method of treating small volumes of water, providing it there is a means of boiling the water which does not attract attention. In an emergency situation, building a wood fire and putting up a plume of smoke is not recommended.

IODINE

Use ordinary household tincture of iodine (2% iodine and 2.4% sodium iodide). For each gallon of clear water to be treated add eight (8) drops of iodine. For muddy or mossy water use 15 to 25 drops of iodine for each gallon of water. Then stir well and allow to stand for thirty minutes. At the end of that period the water should have a distinct medicinal taste; if not, add more iodine. As even backpackers can easily carry a nylon coffee filter, there is no reason for anyone to treat muddy or mossy water!

CHLORINE

Use ordinary household bleach (5.25% available chlorine). For each gallon of clear water to be treated add five (5) to eight (8) drops of bleach. For muddy or mossy water use 15 to 20 drops of bleach per gallon of water. Then stir well and allow to stand for thirty minutes. At the end of that time the water should have a slight chlorinous taste; if not, add more chlorine.  See also Chlorinating Concentrate for a longer lasting, more concentrated form of bleach.

DISINFECTION OF LARGE QUANTITIES OF WATER

Large quantities of water are best disinfected through the use of a chlorine compound. The usual choice is 5.25% bleach. Chlorinated lime may also be used, and has the advantage of being a compact, dense, potent powder, so it takes up less space (volume) than bleach water. But be careful using chlorinated lime: it is a dry fluffy powder you do NOT want to breathe! When using powdered chlorine, it is best to mix the proper amount of powder with a small amount of water, making a paste, then gradually dilute to one gallon and allow the inert material to settle out, then the clear solution should be poured off and used. If the tank has a bottom drain, however, the powdered chlorine can be put directly into the tank, then the precipitate flushed out the bottom through the drain prior to use.

Perhaps the easiest way to disinfect a large quantity of water with the correct amount of chlorine is to use a two step procedure: first make a 1% chlorine solution, then add the 1% solution in the correct quantity to the volume of water to be treated. A diluted solution is easier to measure than mere drops when disinfecting large volumes of water.

Preparation of 1% Chlorine Solution:

To one (1) gallon of water, add 3 1/4 cups of 5.25% household bleach, or one (1) cup of chlorinated lime.

Disinfection of Various Volumes of Water With 1% chlorine solution:

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