View report page

25
Table II.—Averages of the Figures relating to the Treatment of Crude Sewage in Double
Coke-beds at the Northern Outfall Works. (Series II.)
The figures appearing in this table which relate to time previous to 1900 are averages of
the figures which were published in the Third Report. The periods over which the different
averages extend have been determined by the number of fillings of the coke-bed per day or per
week. These were as follows—
One filling per day: July 4th to 15th, 1899.
Three fillings per week: July 17th to September 18th, 1899.
One filling per day: September 21st to December 9th, 1899.
Two fillings per day: December 11th to 15th, 1899.
Table III.—Treatment of Crude Sewage in a Settling-tank and in a Coarse and in a Fine
Coke-bed at the Northern Outfall Works. Record of the Number of Times the
Coke-beds were filled per Day and of the Capacity of the Beds. (Series III).
The period during which the beds were allowed to drain before their capacities were taken
depended upon the number of fillings per day. Generally, when the beds received only one
filling each day, the drainage period was twenty-one hours, with two fillings per day the drainage
period was nine hours, and with three fillings per day it was five hours. It has already
been stated that these differences in the drainage periods did not materially affect the capacity
results.
Tables IV. and V.—Averages of the Figures relating to the rapid Sedimentation and
subsequent Bacterial Treatment of Crude Sewage in a Coarse Coke-bed and in a Fine
Coke-bed at the Northern Outfall Works. (Series III.)
In this series of experiments the crude sewage and the settled sewage during November
and December, 1900, and part of January, 1901, were not separately sampled for the two sets
of settling tanks and beds, hence the figures relating to the crude sewage for the first two
months are the same for each set. After December, 1900, separate samples were taken of the
sewage which was supplied to each bed.
In these experiments the whole of the settled sewage passed through the coke-beds,
therefore, there is only one set of figures relating to the settled sewage. In the corresponding
experiments at Crossness the settled sewage was allowed to run to wast© when the coke-beds
were standing fully charged, consequently the average settled sewage obtained from the settling
tank was not necessarily similar to the average of that supplied to the beds.
Table VI.—Averages of the Figures relating to the Treatment of Crude Sewage in Cokebeds
at the Southern Outfall Works. (Series II.)
This table gives the monthly averages of the daily examination of the crude sewage as
supplied to the 4-foot coke-bed, which was worked on the continuous method of feeding, and
of the effluent from the bed. Although this bed was at work during part of the year 1899
the results of the work were not given in the Third Report on the Bacterial Treatment of
Sewage, because the work had only been in progress for a few months, and no final results had
been obtained.
The other part of this table gives averages of the figures obtained by the chemical
analysis of the crude sewage supplied to the 18-foot coke-bed working on the intermittent
method, and' of the effluent from the bed. The daily analytical figures relating to this bed up
to the end of 1899 were published in the Third Report, but in order to bring the whole of the
results into one table, averages for three periods during 1899 have been included in this table,
together with monthly averages of the results obtained during 1900.
Table VII.—Treatment of Crude Sewage in a Settling Tank and in Coke-beds at the
Southern Outfall Works. Record of the Number of Times the Coke-beds were Filled
per Day, and of the Capacity of the Beds (Series III.)
The figures given in this table refer to experiments of Series III. at the Southern Outfall
Works. On those days which are not included in this list, the coke-beds were not in use, as is
explained on p. 21. Only one measurement was made of the capacity of bed No. 1, namely, on
January 9th, 1900.
The percentage capacities of the coke-beds given in this table are percentages of the
capacity of that portion of the tank which is filled with the coke-bed, assuming that portion
to contain no coke.
Table VIII.—Averages of the Figures relating to the rapid Sedimentation of Crude Sewage
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 crude sewage as supplied to the settling and septic tank used in connection with
the experiments of Series III., and of the settled sewage from the settling tank.
[4]