PURIFICATION. Simply consists of removing or destroying enough impurities to make water safe and pleasant to drink.
4.
a. The first step in purifying is to select a treatment method. (All figures are based on one quart of water.) The three different purifying methods are: (WMC.6.17c) (1)
Boiling. The standard recommendation is to bring the water to a rolling boil for 1 minute at sea level for complete sterilization of the water. Recent research showed that additional boiling time for sterilization was not necessary and that boiling for two minutes at any altitude rendered water safe for consumption.
(2)
Halogens. The number of tablets and contact time must be considered. All charts based on one-quart canteen. (WMC.6.17d)
(a)
Iodine tablets. TYPE WATER CLEAR CLOUDY COLD
(b)
CONTACT TIME 25 MIN 25 MIN 25 MIN
Chlorine bleach. The strength of the solution, number of drops and contact time must be considered.
PERCENT 1% 4-6% 7-10%
(c)
TABLETS 1 2 2
CLEAR WATER 10GTTS/30 MIN 2GTTS/30 MIN 1 GTTS/30 MIN
CLOUDY WATER 20GTS/30 MIN 4GTTS/30 MIN 2GTTS/30 MIN
COLD WATER 10GTTS/60MIN 2GTTS/60 MIN 1 GTTS/60 MIN
Iodine solution. The strength, number of drops and contact time must be considered.
PERCENT 2%
CLEAR WATER 5GTTS/30 MIN
CLOUDY WATER 10GTTS/30 MIN
COLD WATER 8GTTS/60 MIN
(d) Betadine solution. CLEAR WATER 8GTTS/30 MIN (1)
CLOUDY WATER 16GTTS/30 MIN
COLD WATER 8GTTS/60 MIN
Filtration Most filters are not small enough to completely disinfect water. They remove particulate debris, which allows lower halogen dose and improved appearance and taste of "dirty" water. Filters clog quickly if the water is dirty or has a lot of suspended particles. NEVER USE FILTERS AS YOUR SOLE METHOD OF WATER PURIFICATION.
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