WATER
TREATMENT - URANIUM
Uranium in groundwater
is a widespread issue. Uranium is usually found as an anion complex.
The ionic form of uranium is very efficient at making complexes
in water and can have several different forms. They all are anionic
at normal water pH (above 6.5), having a negative charge.
The removal of
Uranium can be accomplished in several ways that have about the
same efficiency. If yoiu need to treat very large volumes of water,
you should look at the EPA presentation linked at the bottom of
this page. If you are only treating drinking water for your house,
an under sink RO will remove 99.8% of it or better. If you want
to treat a larger amount of water, an anion exchange resin in
the chloride form will be more economical and easier to install.
For potable water systems, ion exchange is usually far less expensive
and easier to maintain than a reverse osmosis system.
Both
reverse osmosis (RO) and ion exchange remove almost all of
the Uranium in solution. They are both very efficient. The difference
is that there is a constant waste stream with the reverse osmosis
system and it may require pretreatment of the other water constituents
before it can be used. The RO systems concentrate the Uranium
in the discharge stream. You may be over the level to discharge
if you run it at a high recovery rate. You will need to check
the your local authorities. An under sink RO will not concentrate
it high enough to matter.
An ion
exchange system can run with just filtered water. You can
run with or without regenerations. If your pH is between 6.5 and
8 and you will have a negative ion which can be removed by a strong
anion resin. The ion exchange resin has a very high capacity for
the Uranium ion and will run a very long time before it has to
be changed out. At this writing (updated 2007), ground water source
uranium( not from enrichment) is easily disposed of without special
permitting and is relatively inexpensive to dispose of.
In some cases,
were the local water treatment plants permit, the resin can be
regenerated at a frequency which allow the uranium in the waste
stream to stay under the limit allowed. This has a higher cost
of operation with the frequent regeneration of the resin but the
radiation level of the resin is never very high. . Some locations
will not let you regenerate the Uranium containing resin due to
the salt brine required for regenerations. If the uranium level
is very high, the regeneration frequence may be too often to be
economical. You will need to check with your local authorities.
If your pH is below
5, the uranium is positively charged and you will need a cation
resin. If there is radium in the water, it will also be picked
up by the cation resin and you need to check with the local agencies
to see what your options are. One option is to raise the pH over
6.5 and use an anion resin if the Radium is below the control
level.
Uranium Literature
on the Web
Click on the highlighted
web address to go to the web page listed. Hit back on your browser
(right click mouse) to get back here if you want more.
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