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82-84 UV:SPN Master pages 13/9/08 01:52 Page 3
National Research and Safety Institute
showed an increase of THMs (particularly
chloroform) in pools where the system is in
use. A study by the Danish Technological
Institute in 2002 showed very similar
results. Trihalomethanes (THMs) are
chemical compounds and are
environmental pollutants, and many are
considered carcinogenic.
The report did not recommend a ban on
UV and it made some positive comments
about the system’s effect on reducing
chloramines, but it did highlight
reservations that are so serious they have
stimulated the French Government to
introduce the following regulations:
• Measurements are taken of total
organic carbon (TOC), chlorides and health risk. Pollutants can build up in the
trihalomethanes (THMs) in pool water water and in the air above the pool. You
at least monthly can’t see or smell them, so there doesn’t
• Tests should be taken of nitrogen appear to be problem, and they’re difficult
trichloride and THMs in the air twice to measure.
a year “In the UK, it seems pools are buying
• Ensure there are no more than 100 into UV to reduce fresh water dilution on
micrograms per litre of THMs in the the green ‘low chlorine’ ticket. The report
pool water at any time (as raises concerns that UV could actually be
recommended by the World Health producing other more harmful pollutants
Organisation) than it actually removes. Also, if these
• Pools equipped with UV must use at regulations are adopted in the UK, pools
least as much fresh water as the pool will have to increase the amount of fresh
did before UV installation and not less water they use. Add to that the cost of
than 30 litres per bather per day regular laboratory tests (on top of the
• Ensure that the air renewal rate is existing costs of electricity and
maintained, or if necessary increased, replacement lamp tubes) and the total cost
to the level that existed before UV of running the system would increase
was installed. sharply. In Denmark, the sale of UV
technology into public pools had virtually
The report states that the analyses must be halted after research on real pools was
conducted by qualified laboratories and published by the Danish Technological
that the tests are financed by pool Institute, showing very similar findings to
operators, not the relevant local authority the French.
ABOVE: UV arc tubes like this from Hanovia are
environmental health departments. As well as being regulated in France, the
used also in a range of processes where water
passes through the chamber and the UV kills any
The new regulations will inevitably lead use of UV technology is not included in the microorganisms present by disrupting DNA
to higher costs for the swimming pools German DIN standard or the Austrian
using UV and could be a blow to local Bathing Hygiene Regulations.”
authorities who are using the systems on He adds: “UV has gained a lot of ground THE CASE FOR UV
the premise of cost savings and the ‘green’ in recent years, but we, and other • UV reduces the levels of injected
credentials of using less water for dilution. companies within the pool industry, feel chlorine into the water and also
The French authorities have asked for a that the French study raises some serious reduces the water renewal volume
listing of all French pools using the concerns about its use. As the French have while still maintaining the
system and will be enforcing the done, we’d like to see further independent bacteriological quality of the water
regulations whilst analysing feedback research done in the UK on UV systems in within allowable limits.
about UV from managers. real pools to measure the extent of the • Radiation from the medium-pressure
Specialist pool water treatment company issues here.” UV lamp helps Total Organic carbon
Gaffey Technical Services Ltd has been Hanovia UV specialists said the French removal, which may be the result from
sceptical about the claims for UV study investigated the effects of its partial mineralization.
technology in swimming pools for some medium pressure UV lamp radiation on • Pool chemistry is complex and THM
years and has refused to supply it to water quality in a chlorinated indoor formation is a combination of bather
customers. swimming pool. loadandchlorinelevels. AsUVreduces
Andrew Gaffey explains why: “We have The following conclusions were drawn: organics and allows lower chlorine, it
been concerned for a while that UV may 1radiation from medium pressure UV should mean lower THMs.
cure one problem and create another. lamps led to an increase in active
When UV is used with chlorinated water, it chlorine due to photolysis of combined THE CASE AGAINST UV
is effective in breaking down combined chlorines. It was therefore possible to • UV could actually be producing other
chlorine, as well as some free chlorine, but reduce the levels of injected chlorine more harmful pollutants than it
that creates by-products, including THMs, into the water and also to reduce the removes.
which are recognised carcinogens. water renewal volume while • The action of UV used with chlorinated
Chloramines can’t simply disappear, in still maintaining the bacteriological water, breaks down combined chlorine,
other words, you can’t have a reaction quality of the water within allowable as well as some free chlorine, but
without any consequences. For limits. Hanovia claim this is one of the creates by-products, including THMs,
regular/competitive bathers and lifeguards, main reasons why UV should lead to which are carcinogens.
these by-products could cause a long term reduced THM’s
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