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99
water in amount sufficient to give one part of free chlorine to every
one or two million parts of water, not only is the water sterilised,
or deprived of all organised living molecules, but it is kept sweet
and. free from odour, and there is no tendency in the water to the
deposition of slimy sediments on the floor of the pond. A certain
amount of slimy matter collects on the walls of the pond at the
line where the surface of the water is in continual movement
from the undulatory motions induced by the movements of the
bathers, but this is readily removed with a swab by the attendant.
At Poplar, the hypochlorite of magnesia solution is prepared
by the electrolysis of Water Board water, containing certain
definite proportions of sodium chloride and magnesium chloride.
An elaborate plant has been erected, as the electrolysis fluid is
largely used in the Borough of Poplar as a disinfectant. Seawater
would serve equally well for the manufacture of hypochlorite
solution, as its chief constituents are the chlorides of sodium and
of magnesium. It is quite unnecessary, however, to erect a plant
for the manufacture of hypochlorite solutions, as these can be
obtained as commercial products from the manufacturers of
chlorinated disinfectants.
It should be said that the electrolytic fluid in the Poplar
Baths is not used with idea of rendering unnecessary periodic
changes of the pond water, but to keep the water in the pond fresh
and free from harmful organisms all the time it is in use. The
class of persons who use the swimming ponds in Poplar is always
likely to contain uncleanly or infected individuals, and it is to
guard against danger from the latter that the fluid finds its chief
application.
At Poplar the electrolytic fluid costs in its preparation about
£2 per 1,000 gallons, or a little less than ½d. per gallon. Thirty
gallons are added to a swimming pond of 85,000 gallons capacity
on first filling, and subsequent additions are made as required, at
intervals of two or three days. The bath is emptied weekly or
every ten days."
Comments on Adverse Criticisms respecting the process.
See annual report 1911.
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