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In addition, at four of the Council's schools there are swimming pools, and
there is also a pool at one direct grant school. A local industrial firm operates a bath
at its sports ground at Greenford, and a private bath is provided for the residents of a
privately owned housing estate.
The chlorination of the Council's swimming baths has, over the years, often
been a cause for members of the public to approach the health department. The subject
of chlorination is not generally well understood nor is the need for modem equipment
sometimes appreciated. Put at its simplest, when chlorine is added to the water of a
swimming bath it combines with impurities and results in the formation of compounds
known as chloramines. These, although not so rapid nor so powerful as free chlorine,
are lethal to bacteria. If this method, which is known as marginal chlorination, is
relied upon, however, the chloramines are likely to cause some eye irritation to the
bathers and a smell of chlorine from the bath.
A better method is for further chlorine to be added which breaks down the
chloramines, eventually a point being reached when free chlorine is present. This is
known as breakpoint chlorination and has none of the disadvantages described under
the marginal method. It does, however, require up-to-date and preferably automatic
apparatus. Of the Council's baths, Ealing Central baths has during the year had a
modern automatic system installed. This will enable much more efficient chlorination
of these baths where, up to now, it has been necessary to chlorinate the four
constituent pools to the same level even if they have a widely differing number of
bathers in the pool at the time.
The plant at Northolt, although of modern design, is not automatic. Neither the
Acton or Southall baths have modern equipment.
The Department took samples of water from each pool at regular intervals
throughout the year and these were submitted for bacteriological examination.
A total of 528 samples was taken of which only 11 were unsatisfactory. In the
latter cases repeat samples were found to be acceptable and advice was given where
necessary.
The results are given overleaf.
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