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17
DIVISION II-BACTERIOLOGICAL.
RESULTS OF THE BACTERIOLOGICAL EXAMINATION OF CROSSNESS
CRUDE SEWAGE AND OF THE EFFLUENTS FROM THE COKE-BEDS.
A.—INTRODUCTION.
It has been stated (Division I., Section I., Sub-section 2h) that one of the main objects of the
experiments vras to ascertain—
"The effect of the treatment on the number and nature of the bacteria which were
present in the raw sewage."
This portion of the Report contains a record of the work which has been done in this direction
from May 9th to August 9th, 1898.*
It will be readily understood that, notwithstanding the large amount of work which has been
carried out in obtaining data for this preliminary statement, the period during which the coke-beds have
been in operation is too short to allow of anything in the nature of a final opinion being given as to
their efficiency from the view-point of the bacteriologist. What follows then must be regarded as in
a sense provisional, although it is probable that many of the results which have been obtained, and
some, at all events, of the conclusions that have been arrived at will hold good in future work.
In what follows reference will be repeatedly made to the effluent from the 4-foot coke-bed, to
the effluent from the 6-foot coke-bed, and also to the effluent from the laboratory coke-vessel. This last
is the effluent from the 6-foot coke-bed which has again been treated in the small laboratory vessel at
Crossness. A description of the construction and history of these coke-beds, together with all other
essential particulars relating to them, will be found in Division I. of this Report (pages 7 to 9).
The Committee will remember that they have already received a report dealing with the
bacteriology of London crude sewage as it is delivered at the Barking and Crossness Outfall Works.†
Before proceeding further it is desirable to give a brief summary of the contents of this first report.
B.—SUMMARY OF CONTENTS OF THE FIRST REPORT.
Under tlie heading "Description of some of the Methods used in the Bacteriological Examination of
Sewage," information was given as to (1) collection of samples; (2) dilution of sewage; the best way of estimating
(3) the total number of bacteria; (4) the number of spores of bacteria; (5) the number of liquefying bacteria; and
how to search for (6) special micro-organisms such as B. coli, typhoid bacillus, diphtheria bacillus, staphylococci
and streptococci, and B. enteritidis sporogenes.
Under the heading "Summary of Results shown in Table I.," it was shown that (1) the total number of
bacteria in 1 c.c. of Barking crude sewage averaged 3,899,259 (19 cultures of 9 samples), and in 1 c.c. of Crossness
crude sewage 3,526,667 (11 cultures of 6 samples); (2) the number of spores of bacteria in 1 c.c. of Barking crude
sewage averaged 332 (excluding certain extreme results), and in 1 c.c. of Crossness crude sewage 365 (excluding
extreme results), which gives a ratio of spores to total number of bacteria of 1 to 11,744 and 1 to 9,662 respectively;
(3) the number of liquefying bacteria in 1 c.c. of Barking crude sewage averaged 430,750, and in 1 c.c. of Crossness
crude sewage 400,000, which gives a ratio of liquefying bacteria to total number of bacteria of 1 to 9 and 1
to 8'8 respectively. As regards (6) the species of micro-organisms, it was shown that in Barking and Crossness
crude sewage the spores of B. enteritidis sporogenes were present in numbers varying from at least 10 to about 1,000
per c.c., and B. coli was present in numbers usually exceeding 100,000 per c.c. Notes were also given of the
occurrence of other bacteria such as proteus-like forms, bacillus fluorescens liquefaciens and non-liquefacient B.
mycoides, B. mesentericus, B. subtilis, &c.
In Table I. were given the results of the bacteriological examination of 9 samples of Barking and 6
samples of Crossness crude sewage as regards the total number of bacteria, the number of spores of bacteria and
the number of liquefying bacteria, and as regards the species of micro-organisms present.
A number of micro-photographs illustrating the work accompanied the Report.
It was said (page 1, A., First Report) that the Report was only to be regarded as a preliminary statement
of the progress of the work. By this it was not meant that the amount of work that had been carried out was of
an insignificant character, the contrary was the case, but the subject was one of such a complex nature, and one
about which so little is known, that it might well occupy the energies of not one but many workers for a very
considerable period of time. Had the work merely covered the ground taken up by earlier observers it would
still have been a most desirable thing from a scientific point of view to hare confirmed or modified the results
obtained in the past, particularly in an enquiry dealing with a subject which is still in its infancy, namely, the
bacteriology of crude sewage.
But to a very considerable extent the research covered new ground, as, for example, the determination not
only of the presence but of the relative abundance of a number of different micro-organisms, but more particularly
of the B. coli and the spores of B. enteritidis sporogenes. B. coli is an example of an aerobe peculiarly abundant
in crude sewage, and B. enteritidis sporogenes is an example of a pathogenic anaerobe less abundant, but perhaps
more characteristic of sewage. The importance of obtaining records of the number of these germs in raw sewage
preparatory to a study of their numbers in the effluents from the coke-beds needs no comment to show its
importance. Moreover, such records are highly important from the point of view of the bacterioscopic analysis of
drinking water.
* At the end of the report will be found further bacteriological records (9th August to 31st December, 1898).
in addenda A, B, C, D, B.
†Filtration of sewage. Report on the bacteriological examination of London crude sewage. First Report
(P. S. King and Son, 2 aud4, Great Smith-street, Westminster, S.W.).
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