Environmental Engineering Reference
In-Depth Information
which is shown below, and the associated 'water holding ability', 'lightweight',
'permeability' and 'fertilizer holding ability' were evaluated quantitatively.
WET method
No.1-1 amount of soil particles: paper debris = 0:10 (paper only).
No.1-2 amount of soil particles: paper debris = 4:6
No.1-3 amount of soil particles: paper debris = 6:4
No.1-4 amount of soil particles: paper debris = 7.5: 2.5
No.1-5 amount of soil particles: paper debris = 9: 1
No.1-6 amount of soil particles: paper debris = 9.5:0.5
No.1-7 soil grain Quantity: paper debris = 0:10 (soil particles only).
DRY method
No.2-2 amount of soil particles: paper debris = 4:6
No.2-3 amount of soil particles: paper debris = 6:4
No.2-4 amount of soil particles: paper debris = 7.5: 2.5
No.2-5 amount of soil particles: paper debris = 9:1
No.2-6 amount of soil particles: paper debris = 9.5:0.5
Figure
10.12
shows the test results. The larger the ratio of the amount of soil to the
amount of paper debris means less paper debris is required and a more economic
composition, because the cost of the paper is expensive. Consequently, the mini-
mum additive amount of paper debris which satisfies all target values is the most
suitable amount of paper debris to be added. It is confirmed from Fig.
10.12
that the
most suitable ratio of the amount of soils to the amount of paper debris, and which
satisfies the target values of 'effective water holding ability', 'coefficient of perme-
ability', 'proportion of solid and air phase' and 'cation exchange capacity' is 5.0 in
the DRY soils. On the other hand, in the WET soils, the most suitable ratio between
the soil amount and the amount of paper debris is 6.0, although the target values for
'specific gravity in the wet condition' and 'proportion of air phase rate' were not
satisfied. In other words, if the proportion of soil in the sludge can be calculated and
the amount of paper debris to be added is determined to achieve a ratio of soil to
paper debris of 5.0-6.0, planting soils of fixed quality can be produced from muds
of different water contents.
The test results showed that it was hard for WET soils to satisfy all the perfor-
mance criteria. However, it can be considered that if the proportion of the soil phase
in the planting soils and permeability are increased by allowing some of the gravi-
tational water
2
to drain, all performance criteria will be satisfied. In order to realize
the above conditions, the addition of framework structure materials such as wood
chips in the produced planting soils may be effective.
2
Gravitational water is water which is not attached by absorption to soil particles or in capillaries
and is thus more mobile.
