When a source of water supply is found to be contaminated, every effort should
be made to find an uncontaminated source. When such a source cannot be found,
permission must be obtained from a medical officer before treating the contaminated
a. Removal of Nuclear Contamination.
(1) Nuclear contamination may result from fallout of either fission products
(radioactive isotopes) or nonfissioned products (uranium or plutonium), from blow-in or
wash-in of radioactive dust. and from induced activity in dissolved materials in water
and surrounding soiI. Continuous flow equipment, when operated according to
standard procedure, is capable of removing a large amount of such contamination.
However, sources containing radiological contamination should be avoided if at all
(2) The efficiency of a given process for removal of radioactive materials
from water is dependent upon the quantity of the contaminant that is in suspension in
the water and the quantity that is dissolved in true solution. Removal of material in
suspension is relatively easy since the purification procedure is designed to remove
suspended matter and to clarify the water. Available information indicates that most of
the radioactivity occurring in fallout and debris from the detonation of a nuclear weapon
is insoluble in water. This fact tends to simplify the decontamination problem.
(3) Continuous flow type equipment, with auxiIiary processing equipment
when necessary, removes radioactive material from water using pretreatment,
coagulation, or fiItration, or by using a combination of these methods. Coagulation and
fiItration are normal treatments given to all raw surface waters in operation of field
purification units. Removal of suspended radioactive materials by this method is very
high. Removal of dissolved radioactivity is frequently possible by using ion exchange
equipment. An ion exchange unit operates on the same principle as both commercial
and home zeolite water softeners.
(4) Pretreatment is suggested when the degree of radiological
contamination indicates a combination of treatment methods or when the more effective
ion exchange equipment is not available. Pretreatment consists of batch slurrying the
contaminated raw water with a selected material having adsorptive and ion exchange
capacity. The material of choice is clay, preferably of the montmorriIionite type, that is
high in hydrous aluminum siIicate content. Raw water is slurred at 1,000 ppm for 30
minutes and is then coagulated and fiItered. This series of steps wiII remove most of
the suspended radioactivity and an appreciable percentage of the dissolved
(5) Figure 6-17 illustrates graphically the methods used for normal water
treatment and treatment for removal of NBC contaminants.