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While Mr. Moncrieff was engaged in demonstrating the possibility of disposing of sewage by
the agency of bacteria, other workers appeared in the field. In particular, Messrs. Adeney and Parry
commenced a long series of investigations which has finally resulted in the formation of a company
called The Oxygen Sewage Purification Company. This so-called oxygen system of sewage purification
possesses three main features of interest, namely—
I. The use of crude manganese compounds for the purpose of clarification or
precipitation.
II. The principle of recovering the chemicals employed for the precipitation.
III. The use of nitrate of soda as a substitute for air (and therefore of the coke-bed) for
supplying oxygen to the organisms in the manner required by them.
Mr. Cameron's system was brought forward in 1895 at Exeter. In this system the sewage is
first passed into a closed tank with the object of producing liquefaction of the solid matters by
anaerobic bacteria. The effluent from this anaerobic tank is next passed over an aerating weir and
thence to a series of coke-beds. The arrangement is such that each bed in turn is filled, remains
full for a period, is then emptied, and finally is allowed a rest before being again filled.
In 1897 Colonel Ducat introduced his "aerated bacterial self-acting coke-bed." This is a continuous
filtration process, the raw sewage falling on the surface of the open bed, the walls of which are made
of open drain pipes, and after passing through the body of the bed, which is composed of coarse
material at the top and fine at the bottom, finally escapes without having been exposed to any
anaerobic treatment.
It is unnecessary to describe the system of sewage disposal advocated by Messrs. Dibdin
and Thudichum, because the Committee have from time to time received the records of their prolonged
investigations.
Messrs. Waring and Lowcock, although working on different lines, attempt to bring about
the oxidation of the organic matter in their beds by pumping operations.
At Davyhulme, near Manchester, an interesting series of experiments have been carried out
under the direction of Sir Henry Roscoe with coke, cinder, coal, and sand beds, the treatment of the
effluent from the sewage precipitation tanks being in some cases continuous and in others
intermittent.
II—GENERAL RESULTS OBTAINED AT THE CROSSNESS OUTFALL
(May 9th to Aug. 9th, 1898*).
Under the above heading are given the chief results which have been obtained from the
effluent of the experimental 4-foot coke-bed. The records of the examination of the effluent from the
other beds are too small in number to allow of their being included here, but reference is made to
them in the body of the report.
Total number of Bacteria per c.c.
Crude sewage 6,140,000 (average of 10 experiments)
4-foot coke-bed effluent 4,437,500 (average of 8 experiments)
Percentage reduction 27.7
Number of Spores of Bacteria per c.c.
Crude sewage 407 (average of 10 experiments)
4-foot coke-bed effluent 252 (average of 8 experiments)
Percentage reduction . 38
Liquefying Bacteria per c.c.
Crude sewage 860,000 (average of 10 experiments)
4-foot coke-bed effluent 762,500 (average of 8 experiments)
Percentage reduction 11.3
Spores of B. Enteritidis per c.c.
Crude sewage From 10 to 1,000 (usually more than 100) (11 experiments)
4-foot coke-bed effluent Do. Do. (10 experiments)
Percentage reduction Practically no reduction
B. Coli per c.c.
Crude sewage More than 100,000 (10 experiments)
4-foot coke-bed effluent Do. (8 experiments)
Percentage reduction Practically no reduction
Micro-organisms other than B. Enteritidis and B. Coli.
("In comparing the cultures no distinct difference could be made out, as regards
Chdue sewage the species of microbes, between the cultivations made from the crude sewage
4-foot coke-beds effluent and those made from the effuents.
The records are not sufficiently extensive to allow of final deductions being drawn. Yet it may
be worthy of note that the percentage reduction of spores of bacteria was greater, and the percentage
reduction of liquefying bacteria less than the reduction of the total number of micro-organisms.
*Some of the later results (Aug. 9th to Deo. 31st, 1898), are given in Addenda A, B, C, D, E. It must
however, be understood that the descriptiTe matter in this report deals only with the results up to Aug. 9th.
Nevertheless, the general results obtained since then do not differ very widely from those here recorded.