View report page

27
Colour—m.m. brown 2 ft. Tube Burgess's
Tintometer 13
Hardness (total) 264
Hardness (non-carbonate) 66
pH value 7.9
Phosphate as PO4 0.95
Silicate as SiO2 9
Suphate as SO4 58
Fluoride as F 0.25
Magnesium as Mg 4
Surface active material as Manoxol 0.12
Electrical conductivity (gemmhos) 550
The above figures are given as milligrammes per litre unless
otherwise stated.
Bacteriological Results (after treatment)
Number of samples 1,778
Agar plate count per ml. (20-24 hours at
37 °C.) 14.4
Coliform count—per cent, samples negative
in 100 ml 100
PUBLIC SWIMMING BATHS.—Water for the Baths in the
Borough is supplied from the Metropolitan Water Board's mains.
Apart from the routine tests mentioned below, samples of water
from each Bath were submitted for chemical analysis and bacteriological
examination by the Public Analyst in September. All the
samples were reported to be satisfactory.
The following details have kindly been supplied by the Manager
of the Baths:—
There are two Swimming Baths in the Borough (Porchester
Baths and Kensal Road Baths) each establishment having a large
and a small Bath. The large Baths are open from May to September
and the small Baths are open all the year round. There were
approximately 171,000 attendances during the year (116,000 at
Porchester Baths and 55,000 at Kensal Road Baths).
A high standard of purity of bath water is maintained by
continuous flow through pressure type sand filters, the water being
treated by coagulants to flocculate organic matter, and then chlorinated
to a marginal chlorination standard of 0.2 to 0.5 parts per
million. The alkalinity of the bath water is determined by the use
of soda ash treatment and a pH value of 7.2 to 7.8 is maintained.
Finally the water is aerated and reheated to 76°—78° F. Cleansing
of the sand filters is brought about by a reversal of the flow of water
to break up the solidified sand bed, assisted by rocking the filters
and the use of steam/air agitation. The normal daily consumption
of fresh water added to the bath following filter cleansing equals
approximately one-twenty-fifth of the bath capacity. The swimming
baths are completely emptied, cleaned and refilled once a year.