(3) Fill the cap of a plastic canteen half full of the solution in the cup and add
it to the water in the canteen, then place the cap on the canteen and shake it
thoroughly. This mixture provides a dosage of 10-15 ppm active chlorine.
NOTE: If an aluminum one-quart is being used, add at least three capfuls of the
calcium hypochlorite solution to the canteen as this cap is much smaller than
the one on the plastic canteen.
(4) Loosen the cap slightly and invert the canteen, letting the treated water
leak onto the threads around the neck of the canteen.
(5) Tighten the cap on the canteen and wait at least 30 minutes before
using the water.
c. Field Expedient Methods. When neither the issue calcium hypochlorite
ampules nor iodine tablets are available, several improvised means of disinfection may
(1) Boiling. Boiling is used when disinfecting compounds are not available.
It is a good but not the best method for killing disease-producing microorganisms. It has
several disadvantages: (1) fuel is needed; (2) a rolling boil for 5 to 10 minutes is
needed to kill most microorganisms and then it needs to cool (in an emergency, even
water boiled for 15 seconds would help; (3) there is no residual protection against
recontamination; (4) Clean, closed containers must be used to store the water.
(2) Tincture of iodine. Ordinary tincture of iodine may be used in the same
manner as iodine tablets. Each drop of tincture of iodine will supply a dosage of I ppm
of active iodine in a one-quart canteen; therefore, 8 or 16 drops should be used,
depending, upon whether the water is clear or cloudy.
(3) Household bleach. Commercial brands of household bleach are
normally 5 percent active chlorine (the percentage may be found on the label). One
drop of 5 percent bleach will provide approximately 2 1/2 ppm available chlorine in a
one-quart canteen of water; therefore, 2 drops will suffice for a 5 ppm dosage, or twice
that amount for a 10 ppm dosage.