The Japanese water-purification kit shown below is intended for use in rendering water
found in the field fit for human consumption by chlorinating and destroying harmful
bacteria. The kit consists of two vials of "germicide" (the chlorinating agent), one
vial of neutralizing agent, a small aluminum spoon, and a metal box with a hinged lid.
The chlorinating agent is composed of a mixture of calcium and sodium hypochlorites; active
chlorine content is 7.05 percent. The neutralizing agent, used to destroy the chlorine, is
sodium thiosulfate. The vials of germicide contain about 5 grams (0.18 oz) of the agent, while
the vial of neutralizing agent contains 5.3 grams (0.19 oz). The cork ends of the vials are
dipped in paraffin wax for protection of the contents. The metal box measures 1.75 by 0.6
by 3.4 inches and is fitted with a cardboard liner to protect the glass vials.
b. Directions for Use
A label pasted to the top of the box gives the following directions for use:
(1) Put one spoonful of the germicide into a flask (about 1 quart) full of water. Insert
the cork and shake well for about 5 minutes.
(2) After a further 5 to 10 minutes have elapsed, add one spoonful of the neutralizing
agent and shake.
(3) Wipe the spoon thoroughly after using.
Comment: The spoon holds from 3 to 4 grains and a single kit can therefore be used
from 15 to 20 times.
There has been very little progress in the development of newer methods of individual
water purification since the days of World War I. Purification of water by the
individual ordinarily consists in using a fixed dose of chlorinating agent for a given
volume of water, but a more effective procedure involves hyperchlorination followed
by dechlorination. The latter method demands the use of considerable judgment on the
part of the individual soldier if proper water disinfection is to be accomplished, since
if the dechlorinating agent is added before the chlorine, or too soon after the addition
of the chlorine, disinfection of the water will not take place. Because of the variable
chlorine demand of natural water supplies encountered in the field, the amount of chlorine
that is specified for some water is insufficient for others; therefore, fixed-dose
chlorination is not always satisfactory.
Investigations have been conducted during the past 2 years to develop a simple method
which will, in one operation, hyperchlorinate the water and dechlorinate it after the
proper interval. The solution to this problem should be forthcoming very soon, and should
furnish a fool-proof system, and one unlike the cumbersome Japanese-type procedure. In the
meantime, the safest and most efficient all-around method of individual water purification
now available is being supplied to American troops. Halazone tablets, when employed in
accordance with the directions contained on the label of the container, will giver
proper water disinfection in practically all instances. In a few circumstances where
the chlorine demand of the water is excessively high, there may be insufficient
disinfection. However, evidence would indicate that this will occur less frequently and
be less hazardous than the possibility of dechlorinating water at the wrong time under
the method of chlorination and dechlorination as now practiced by some armies.