Environmental Engineering Reference
In-Depth Information
with:
liquid flow (m
3
/s)
Q
l
=
stream through surface (m
2
)
K
l
=
A
=
permeability (m
2
/(Pa.s))
δ
p
/
δ
s
=
pressure drop (Pa/m).
The permeability can also be expressed by an intrinsic permeability,
K
il
.This
intrinsic permeability is dependent on the granule size of the soil matrix, uniformity
of the soil, porosity and the moisture content. The value of
K
il
is a physical property
and is independent of the water flow and pressure differences.
K
il
=
η
l
∗
K
l
(21.14)
with:
intrinsic permeability (m
2
)
K
il
=
η
l
=
dynamic viscosity of water (kg/(m.s))
=
(Pa.s).
The dynamic viscosity of water is 1
∗
10
-3
(Pa.s). For high permeable soils
the value of
K
il
is 1.2
∗
10
−
12
m
2
(
=
1.2 Darcy) and for low permeable soils
1.2
∗
10
−
14
m
2
(
0,012 Darcy). The intrinsic permeability is often given in cm
2
or
=
1
∗
10
−
8
cm
2
). The value of the permeability of water in soil
can vary by one order of magnitude at the same location (Hinchee 1994). At very
low permeability's like in clayey or loamy soils In Situ treatment by liquid transport
as in pump and treat approaches is limited.
in Darcy (1 Darcy
=
Permeability of Soil Gas
The permeability of air (
K
g
) is of especial importance for bioremediation in the
unsaturated zone. In analogy with Darcy's Law for liquid transport, the gas transport
in soil can be described by:
Q
g
A
=
K
g
∗
δ
p
(21.15)
δ
s
with:
gas flow (m
3
/s)
Q
g
=
stream through surface (m
2
)
K
g
=
A
=
permeability (m
2
/(Pa.s))
δ
p/
δ
s
=
pressure drop (Pa/m).
The permeability of soil gas can also be described by an intrinsic permeability
in analogy with the permeability of water. The value of
K
g
is a physical parameter
depending on soil and is independent of the injection of airflow and pressure drop.
K
ig
=
η
g
∗
K
g
(21.16)
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