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Section C—Sanitary Circumstances.
Water Supply.
The greater part of the urban district is within the supply area
of the Sutton and District Water Company, only some 170 dwellings
in the extreme north end being supplied by the Metropolitan Water
Board.
The company employs a full-time chemist/bacteriologist and daily
sampling of the raw and finished waters is carried out. By arrangement,
water received by the consumer is sampled twice monthly as a
routine according to a rota agreed by the local medical officers of the
constituent districts. Additional samples are taken when circumstances
indicate the desirability.
The water, derived from chalk wells, is subjected among other
processes to softening by lime and to chlorination, treatment being so
arranged as to leave a trace of residual chlorine in the finished product.
The following, which is representative, is the report on one of the six
samples taken by the Council during the year: -
Chemical analysis in parts per 100,000.
Total silid matter in solution (dried at 180° C.) 15.8
Combined chlorine 1.45
Nitric nitrogen 0.44
Nitrous nitrogen 0.004
Ammonia, free and saline 0.002
Ammonia, albuminoid 0.001
Oxygen absorbed from permanganate in 4 hours at 26.7° C. 0.006
Hardness—by acidimetric triation—Temporary 8.4
Permanent 3.2
Total 11.6
pH 7.6
Reaction for free chlorine; positive, equivalent to 0.05 part per million.
The water was bright and clear and was normal in colour.
Bacteriological examination.
Action by free chlorine during transit of the sample was prevented
at the time of sampling.
Number of colonies per ml. developing upon agar in 2 days at 37°C. 0
Number of colonies per ml. developing upon agar in 3 days at 22° C. 1
Organisms of the coliform group absent in 100 ml.
Streptococci do.
C1. welchii do.
This water is of high organic purity and its bacteriological condition is excellent.
The water is suitable for the public supply.
The supply is not regarded as having any particular plumbo-solvent
action.
All dwellings have a piped water supply to the house ; none depends
on a stand pipe.
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