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59
The waters used in the boilers at the pumping stations are softened by treatment
with soda-ash and lime, so that the scale-forming constitutents, which are detrimental
to the boiler itself and which prevent also the available heat of the coal from being
utilized economically, are reduced to a minimum. Where the feed water is of
practically constant hardness the "softening" is effected automatically, but
examinations are made daily so that any necessary adjustment of the quantities
of chemicals added may be made. At one station, where the feed water is
taken from the river, the hardness varies considerably owing to tidal effect and
automatic softening is not practicable. In this case samples are examined twice
weekly and information as to the amount of chemicals to be added is supplied to
the station. During 1930 an average hardness of 34.5 was reduced to 9.1 at this
station, a reduction of about 74 per cent.
Refrigerants.
During alterations at an engine house at Abbey Mills pumping station trouble
was experienced with water in the foundations. As the amount showed no signs
of diminishing despite pumping, samples of the water were examined and it was
found that its composition was not dissimilar from that of spring water found in the
vicinity and did not resemble either land drainage or river water as was suspected.
The question of the installation of multiple refrigerator systems in residential
flats has been under consideration. It appears that the advantages of a central
condensing plant for the refrigerant used are great, but it is evident that much
care must be exercised in the choice of refrigerants. Methyl chloride, which presents
some advantages, has been found to be very undesirable in domestic installations
owing to its toxic properties being unaccompanied by any warning irritant smell.
Other refrigerants, such as ammonia and sulphur dioxide, give a warning in this
way when a leak occurs, but in a house pipes charged with these gases, on account
of this liability to leak, must always be regarded as an added danger to the inmates
of the house.
River
Wandle.
An examination of this river was made by the chemist and a representative
of the chief engineer. Both visual evidence and the chemical examination of samples
collected at various points showed that this river, which is already contaminated
when it reaches the county of London, continues to receive both domestic and industrial
pollution on its course through the county towards the Thames. It is interesting
to note that the late General Sir Desmond O'Callaghan in an autobiographical work
(Guns, Gunners and Others, p. 254) refers to having obtained permission as a boy
in the early fifties of last century to fish for trout in "The beautiful Wandle before
ignorant savages turned it into a sewer." The question of the future treatment
of the Wandle with a view to improvement is under consideration by the Council.
Swimming
baths
(indoor).
Two indoor swimming baths at Lyham Road (Brixton) and "Blackfriars"
(Southwark) Schools were visited and comparative examinations made of the water
used for filling the bath and that remaining after use when he bath was about to be
emptied. Although the boys using both baths were very clean and apparently of
clean habit in using the baths, the water after use in each case contained much matter
in solution and suspension and was heavily contaminated with micro-organisms.
This is the inevitable result of many persons bathing in water not continually sterilised.
Experience with outdoor baths in the Council's open spaces has shown the great
improvement following the installation of plant for filtration followed by chlorination.
A clear, practically sterile, water can be maintained for months with large numbers
of bathers using the baths with considerably less effective supervision than school
children receive.
Swimming
baths(open
air).
For the purpose of ensuring that the water in these baths is reasonably clean
and suitable from the point of view of freedom from suspended matter (green growth,
etc.), the waters have been examined from time to time and advice given to the
parks department as to the desirability of changing the water. In the case of the
natural lakes and unfiltered swimming baths the standard of purity cannot, of course,