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Table IX.—Averages of the Figures relating to the Treatment of rapidly Sedimented
Sewage in Coke-beds at the Southern Outfall Works. (Series III.)
This table gives the monthly averages of the whole of the figures relating to the chemical
analysis of the portion of the settled sewage from the settling and septic tank which was supplied
to the coke-beds used in connection with the experiments of Series III., and of the effluents
from the coke-beds. •
Table X.—Particulars as to the Disappearance of Sludge in the Settling Tank at the
Southern Outfall Works. (Series III.)
The data given in this table are derived from actual estimations. They are given for the
purpose of indicating the manner in which the figures representing the amount of solid matter
liquefied in the septic tank have been obtained. Full details of the various figures will be found
on p. 22 of this report.
Table XI.—Results of the Incubation at 80°F. of Settled Sewage, of " Chemical " Effluent
and of Coke-bed Effluent at the Southern Outfall Works. (Series III.)
This table gives the analytical details and the results of the examination of samples of
settled sewage, of "chemical" effluent and of coke-bed effluent which had been kept in an incubator
for seven days.
Table XII.—Average percentage purification effected by the Chemical Treatment and
subsequent Sedimentation of the Sewage, by the Settling Tanks used in connection
with Coke-beds and by the Various Coke-beds at the Outfall Works.
The purification is calculated from the relative quantities of oxygen absorbed from permanganate
by the liquid, both before and after treatment. The two sets oi figures represent the percentage
removal of total putrescible matter (the crude liquid), and of dissolved putrescible matter
(the clear liquid). Except in the case of the figures representing the purification effected by
the chemical treatment and subsequent sedimentation, each set of figures represents the actual
purification effected only by the individual tank or bed. Any purification effected on
the liquid previous to or subsequent to that effected by the tank or bed in question has
not been considered in the calculations.
The figures in this table indicate the amount of purification effected by each single bed
on the liquid with which it dealt. No preliminary treatment of the liquid before it was supplied
to the bed has been taken into account. The percentages merely measure the value of the work
performed by each bed. Figures representing the average percentage purification effected by
the chemical treatment and subsequent sedimentation during the years 1900 and 1901 are added
foT the sake of comparison.
Table XIII.—Average percentage purification of the Crude Sewage effected by the Various
Methods of Experimental Bacterial Treatment and by the "Chemical Treatment"
carried out at the Outfall Works.
The amount of purification effected is calculated from the figures representing the amount
of oxygen absorbed from permanganate by the crude sewage and by the final effluents from
each treatment.
Whereas the preceding table affords an opportunity of comparing the amount of work
performed by each coke-bed on the liquid with which it dealt, this table sets forth the amount
of purification) effected on the crude sewage by the tanks and coke-beds used in the various
experiments at both Outfall Works. The amount of purification recorded in this table is that
which was effected by the whole process of each experiment. The figures have been calculated
from the relative amounts of oxygen absorbed from permanganate by the crude liquid and
by the clear liquid of both the raw sewage and the final effluent.