water circuits must be decontaminated too. You will need to implement the following protective measures if
the use of chemical or biological agents or nuclear weapons is expected:
Secure covers and caps on all open water tanks and bags.
Close doors and other openings on water purification units.
Close manhole covers, spigot box covers, and pumping compartment doors on water trailers and water
Place protective tarpaulins over water purification units, distribution equipment, and water containers.
Move small portable water containers, such as FAWPSS and water cans, under shelter or into enclosed
The following procedures are to be used when your water point is isolated from a NBC defense company or
detachment that is responsible for organized decontamination of equipment and personnel.
External Decontamination. To decontaminate ROWPU equipment externally, you will direct your
personnel to first use a simple, clean water wash down procedure. Usually this will do the job. The nerve
agent GB, for instance, is soluble in water in all proportions and is readily washed away. If a simple wash
down procedure is not completely successful, resort to the use of decontaminants. This applies especially to
cases of CW contamination. In the case of BW agent contamination, you can use fumigants such as EYO or
carboxide. Water purification personnel work with an effective chemical and biological-agent decontaminant
called calcium hypochlorite. You can use this chemical for decontamination of equipment surfaces by
following the preparation and use procedures described below:
Preparation: Have your personnel dig a soakage pit or construct a sump into which you will discharge
the decontamination waste and rinse water. Personnel must wear personal protective equipment and
prepare a 3% solution of chlorine by adding 3 canteen cups of calcium hypochlorite to 6 gallons of water.
Use: Apply the solution to the exterior of the equipment or container using brushes or brooms. One
gallon of the solution should cover 8 square yards. The decontamination solution must remain in contact
with the surface for at least 30 minutes. Reapply occasionally to keep the surface wet. After 30 minutes,
thoroughly wash the surface with water.
Internal Decontamination. The following information describes how to decontaminate the internal
water circuits of the ROWPU equipment. The three basic contaminants, NW, BW, and CW will be
considered in turn.
Nuclear decontamination of a ROWPU involves two types of decontamination. Gross decontamination
relies upon quick, reasonably effective methods that can be applied in the field to remove the bulk of the
contamination. Detailed decontamination, in contrast, relies upon a lengthy, thorough process carried out in a
rear area and intended to restore the equipment to its original clean condition. Decontamination of equipment
contaminated by NW agents should proceed with an understanding of the following basic facts:
Contamination with radioactive substances does not occur evenly. It attaches to rough and porous
surfaces and those surfaces subject to scaling or encrustation.
Some radioisotopes are more readily absorbed on surfaces than others are. Radiological contaminates
(unlike chemical or biological contaminates) cannot be inactivated, neutralized, or destroyed. No degree
of heat, cold, or chemical reaction can speed up or slow down the rate of decay. Time is the only factor
Decontamination should always proceed using mild methods first and then proceed to harsher methods.
Before proceeding with radioactive equipment decontamination, you need to establish the degree of
contamination acceptable. Often doing this is difficult because most of the contamination will be inside
pipes or pumps. Positive radiation readings outside the plumbing can be obtained only when the
contaminating material is a gamma emitter. If the contaminating material emits alpha or beta rays, the
particles are often shielded by the equipment walls. In such cases, you will need to instruct your
personnel to open the equipment by loosening a union and removing a section of pipe. Then you will
have them insert a beta-gamma survey meter, such as IM-141/AN/VDR-2 radiacmeter, directly into the
pipe as a probe.
During biological decontamination of a ROWPU, materials used for decontaminating the circuits of water
purification equipment contaminated with BW agents should be effective disinfectants, rapid in action,
nonhazardous, noncorrosive, and available in quantity. Although very few materials meet all these criteria,
many are used in spite of certain disadvantages such as the previously described use of calcium
The basic materials used for chemical decontamination, STB and soap and water, are also effective
effective method of decontaminating the water circuits of ROWPU equipment is rinsing with pure
uncontaminated water. This method simply dissolves the agent away. In addition, hydrolysis usually takes