DURRIDGE RAD H2O, Руководство пользователя

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[Prichard, Whittaker, Hahn (Method 913.0), Lowry,
Vitz, Kinner, Hess]
In comparison with the above, the RAD H
2
O o ff ers a
method as accurate as LS but faster to the fi rst
reading, portable, even less labour intensive, and less
expensive. It also eliminates the need for noxious
chemicals.
2.6 Mitigation Strategies
Two main strategies have emerged for the removal of
radon from water. Both of these are applicable to
point-of-entry (POE) water treatment in residences
and small public water supplies.
Granular Activated Carbon (GAC) attempts to fi lter
the water by adsorbing radon on a charcoal bed that
holds onto the radon until the radon decays. GAC
systems can be e
ff ective and relatively inexpensive for
residential use, but can create new problems. As the
radon and its progeny decay in the GAC column,
they give o
ff gamma radiation. Th e gamma radiation
may be a health concern to residents when the
in
fl uent radon concentration is high, the GAC
column is poorly shielded for high energy radiation,
and the residents are likely to spend signi
fi cant
periods of time in the radiation fi eld. Over time, a
long lived decay product, lead-210, builds up in the
column, which may pose disposal problems in
systems with moderate to high radon concentrations
in the in
fl uent. For that reason GAC is most o ft en
recommended for in fl uent concentrations of up to
around 5,000 pCi/L. GAC maintenance is simple and
inexpensive, and the GAC bed has an expected
service life of 5 to 10 years. [Henschel, Lowry, Rydell]
Aeration brings water into contact with a stream of
low radon air, which strips the radon from the water,
then exhausts the radon bearing air to the
atmosphere. Aeration systems o
ff er e ff ective removal
of radon without the buildup of gamma radiation or
waste material, but tend to be substantially more
expensive than GAC to install and maintain in a
residential setting. Aeration can be used over the
entire range of in
fl uent concentrations, though very
high in fl uent concentration may require a multiple
stage system to reduce the e ffl uent concentration to
acceptable levels. [Henschel, Lowry, NEEP]
Section 2 Background 15