The standard requirement for chlorine residual in water treated under field
conditions is _______________________ parts per million (ppm).
The standard time allowed for disinfection from the time chlorine is added until
the time water is consumed is:
a. Ten minutes.
b. Twenty minutes.
d. Forty minutes.
The continuous flow type water purification unit used by the Corps of Engineers
is called an ________________________________.
Which of the following factors increase(s) the required chlorine residual in water?
a. Low pH (below 5.0).
b. High pH (above 5.0).
d. High temperature.
e. The presence of chlorine-demanding substances.
Quartermaster and preventive medicine units test water for chlorine residual and
pH with the___________________________.
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