Water Purification

Generally speaking, places that you will go for outdoor day activities or overnight camping will have drinkable water available from a faucet. However, as part of your Planning Ahead, check with the rangers or land managers for the site to ensure that water approved by the Health Department is available. Purifying water removes bacteria, viruses, giardia, and cryptosporidium that may cause illness.  All surface water (streams, lakes, springs, etc.) should be considered suspect and should not be drunk untreated. How to Purify Water If the water at the site needs to be purified before drinking, there are several methods available: Boiling Filtering Chemical Treatment Boiling Bring the water to a full rolling boil (not just bubbles on the bottom of the pan). Advantages: All bacteria and viruses are killed. Disadvantages: Requires a stove, fuel, time.  Resulting water is hot, which is not very refreshing in the summer.  Doesn't remove sediment from water. Filtering Use a commercially available water filter (e.g., MicroPur, Katadyn) to filter water. Advantages: Depending on filter used, all viruses and bacteria as small as 5 microns are removed from water.  Water is cold.  Water is immediately available after pumping. Disadvantages: Slow for a large group. Filters are expensive and can break if not handled carefully. Sediment can clog filter. Chemical Treatment Use a commercially available chemical such as iodine or chlorine dioxide to kill bacteria and viruses. Advantages: Cheap for iodine, moderate price for chlorine dioxide. Disadvantages: Unless neutralizer is also used, water tastes like iodine.  AquaPur can be expensive for a large group.  Purification can take between 30 minutes and 4 hours for full effectiveness.  Sediment is not removed.  Some people are allergic to iodine. Let's Review: 1) On Girl Scout outings, treat any water that hasn't been approved by the health department.      A)  True      B)  False 2) Acceptable methods of treating water are:      A)  Boiling      B)  Filtering      C)  Adding iodine pills      D)  Adding vinegar      E)  A, B and C 3) When treating water by boiling, how long should you boil the water?      A)  Bring to a full rolling boil      B)  Five minutes      C)  Ten minutes

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