emergency preparation of safe drinking water

emergency preparation of safe drinking water

The purification of water when only unclean water is available or when the available drinking water is believed to be contaminated. Any one of the following methods may be used: 1. Water is strained through a filter and boiled vigorously for 30 min. 2. Three drops of alcoholic solution of iodine are added to each qt (approx. 1 L) of water. The water is then mixed well and left to stand for 30 min before using. 3. Ten drops of 1% chlorine bleach, 2 drops of 4% to 6% chlorine bleach, or 1 drop of 7% to 10% chlorine bleach is added to each qt (L) of water. The water is then mixed well and left to stand for 30 min. If the water is cloudy to begin with, the amount of chlorine is doubled.

When the water is contaminated by Giardia organisms, heating to 55°C (131°F) kills the protozoa (method 1). Methods 2 and 3 also kill the cysts, but more time is required. Bacteria and viruses are killed by water kept at 60°C (140°F) for 30 min.