indicates the probability that agents of nonbacterial waterborne diseases such as
amebiasis, infectious hepatitis, or schistosomiasis are present.
ARMY CHLORINATION POLICY
a. Fixed Installations. The purpose of chlorinating potable water supplies at
fixed installations is to disinfect the water before consumption and to provide residual in
the distribution system. Demonstration of a proper residual indicates that the system is
operating satisfactorily, while a reduction in the strength or absence of a residual may
be associated with contamination of the system. The amount of residual and the
contact time necessary to assure destruction of pathogenic microorganisms are
dependent upon the pH and temperature of the water and whether the chlorine is acting
in a free or combined state.
(1) Unless an installation is served by a public water system approved by
the appropriate health authority, chlorination must be sufficient to provide a measurable
residual of free available chlorine at all times in all parts of the potable water distribution
system under constant circulation.
(2) Where disinfection must be assured because of sanitary deficiencies in
production, purification, or distribution, the chlorine residual must not be less than the
values shown in Table 2-1.
b. Field Water Treatment. Engineer field water treatment equipment, when
properly operated, produces a water of high quality, free of turbidity, suspended solids,
and parasitic, ova. The disinfection that is included inthe continuous flow purification
process is for the purpose of providing a margin of safety against bacteria and viruses
pathogenic to man. As previously mentioned, the effectiveness of chlorination is
dependent upon the pH, the temperature, and the contact time. The chlorine dosage
used in field water treatment must be sufficient to produce finished water which, after
a30-minute contact time, will have a free available chlorine residual at least as high as
shown in Table 2-1. If adequate provisions are not made for accurate and frequent
measurement of pH, a residual of 5.0 ppm FAC must be maintained. In areas requiring
veridical or cysticidal treatment, a minimum residual of 10.0 ppm FAC must be
maintained. Procedures for measuring pH and chlorine residuals are discussed in
c. Individuals and Small Units. When potable water provided by standard
water purification equipment is a not available, individual and small units must treat their
own water in Lyster bags, canteens, and other water containers (paras 2-10, 2-11).
These purification methods do not include the removal of impurities by coagulation and
filtration; therefore, the entire reliance for rendering the water safe for consumption is
placed on the disinfection process. The chlorine dosage must be sufficient to provide a
residual of at least 5.0 ppm (or 10.0 ppm where veridical/cysticidal treatment is
indicated) after a 30-minute contact period.