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Water Purification Methods


There are two types of chemical treatment: those using iodine and those using chlorine. There are a variety of products on the market, so follow the directions on the bottle. For tablets, pay close attention to the expiration date because many of them will not work effectively once the date has passed.  Once the bottle has been opened, the tablets must be used within a certain period.  If they are not they will cease to work properly. If there is any doubt, buy a new bottle. Remember that chemical purification methods may only be partially effective, depending on the water temperature.

The effectiveness of all chemical treatment of water is related to the temperature, pH level, and clarity of the water. Cloudy water often requires higher concentrations of chemical to disinfect.  If the water is cloudy or filled with large particles, strain it, using a cloth, before treatment.

After you add the chemical to the water, swish it around to aid in dissolving. Splash some of the water with the chemical onto the lid so that all water areas are treated. The water should sit for at least 30 minutes after adding the chemical to allow purification to occur.

Cold water is less effective when using a chemical as a purifying agent. If the water temperature is below 40° F (4° C), double the treatment time before drinking. It is best if water is at least 60° F (16° C) before treating.
Chemically treated water can be made to taste better by pouring it back and forth between containers, after it has been adequately treated. Other methods include adding a pinch of salt per quart or adding flavorings (e.g., lemonade mix, etc.) after the chemical treatment period.

Iodine is light sensitive and must always be stored in a dark bottle. It works best if the water is over 68° F (21° C). Be aware that some people are allergic to iodine and cannot use it as a form of water purification. Persons with thyroid problems or on lithum, women over fifty, and pregnant women should consult their physician prior to using iodine for purification. Also, some people who are allergic to shellfish are also allergic to iodine. If someone cannot use iodine, use either a chlorine-based product or a non-iodine-based filter.

Chlorine can be used for persons with iodine allergies or restrictions. Remember that water temperature, sediment level, and contact time are all elements in killing microorganisms in the water. No matter what procedure you choose though – it is essential to purify contaminated water before drinking.