The lyster bag shown in figure 2-23 is primarily a
dispensing unit for purified or distilled water. These
bags are sturdy, watertight, and readily collapsible for
packing. Water is withdrawn through small faucets at
the bottom. When no other purification equipment is
available, the lyster bag can be used to disinfect raw
water. Chemical kits for purification are supplied with
each lyster bag. When you must use a lyster bag for
water treatment, follow the manufacturers
Tank trailers (fig. 2-24), like lyster bags, are
designed as dispensing units for purified or distilled
water; however, tank trailers may be used to disinfect
raw water. The water is treated as directed by local
The tank trailer, sometimes referred to as a water
buffalo, has a capacity of 400 gallons of water. The
unit comes equipped with faucets for dispensing the
water. When desirable, water can be transferred from
the tank trailer into a lyster bag. The responsibility for
cleaning and disinfecting the tank trailer before it is
filled with water belongs to the Utilitiesman.
Figure 2-23.Lyster bag.
Figure 2-24.Tank trailer.
Disinfection destroys harmful organisms
(pathogenic viruses, bacteria, and protozoans) present
in water by exposing them to specific concentrations of
disinfecting agents or to heat. The Navy guidelines on
disinfection are as follows.
The superchlorination process is used to disinfect
water containers (lyster bags, tank trailers, etc.) and
distribution systems initially- before they are used or
when they have become contaminated.
Superchlorination is accomplished by chlorinating the
water in a container or distribution system to at least
100 ppm FAC and holding it in the container for 4
hours. During the 4-hour period, the FAC must not drop
below 50 ppm. If the ppm falls below 50 ppm the
process must be repeated. A sign POISON DO NOT
DRINK must be displayed clearly on all sides of the
container or at all water outlets during this process.
Using the three charts in table 2-2, choose the one
that applies to the percentage of HTH material you
intend to use. Lets say the chief gave you a bottle of
65% granular calcium hypochlorite. You should use
the chart that has the title For 65% to 70% Granular
Calcium Hypochlorite. Now locate the amount of
water you are going to treat. For our example here, lets
say that we are going to treat a 400-gallon tank trailer.
Look on the correct chart and locate the quantity in
gallons. There is no 400-gallon figure, so use the larger
capacity of 500 gallons. Now follow over on the chart
and locate the corresponding number of ounces to add
to receive a 100 ppm FAC. The answer is 10 ounces. We
have determined that 10 ounces of 65% calcium