Geoscience Reference
In-Depth Information
3. Seawater Infiltration Experiment by Alluvial Soil
with Organic Carbons
A square water tank 190 cm
190 cm with a perforated bottom was pre-
pared as follows: coarse sand was laid onto a neutral media base in the
tank to an even depth of 5 cm and this was covered with a layer of paddy
soil, containing oxides of Fe and Mn 30 cm deep. The water level was main-
tained to a depth of 12 cm above the paddy soil surface. The chemical
components of soil are summarized as follows (weight content (%)): Fe
2
O
3
;
5.34%, MnO
2
; 0.05%, Al
2
O
3
; 8.09%, SiO
2
; 77.58%, Organic matter; 6.08%,
C; 1.96%, H; 0.76%, N; 0.15%. Cation exchange capacity of the paddy soil
is 5.724 (mmol/100 g). The calculation condition are as follows; calculation
depth: 30 cm, calculation period: 60 days, grid mesh size: 0.5 cm, time incre-
ment: 30 s, cross sectional velocity: 1
.
385
×
10
−
5
cm/s,
θ
w
= 48%,
θ
bio
=2%,
×
10
−
2
mmol/l.
θ
mat
= 50%, IC
NO
3
=1
.
0
×
4. Application of the Numerical Simulation Model
The results of numerical simulation for the entity species after 60 days
at 29.5 cm (the grid of the boundary of alluvial soil and coarse sand of
the experimental setup) are shown in the right column in Table 1. The
parameters used in the simulation model are listed in Table 2, respectively.
Comparing with the analyzed and the calculated value of the chemical
species concentration of euent seawater concentration, it can be noted
Table 1.
Measured and calculated concentration of seawater.
Analyzed values
(after 60 days of infiltration)
Calculated
Infiltrated seawater
E
uent seawater
e
uent seawater
Measured species
concentration
concentration
concentration
DO (meq/l)
0.200
0.016
0.121
Ca
2+
(meq/l)
21.1
20.3
20.3
Mg
2+
(meq/l)
98.7
107.0
107.0
Na
+
(meq/l)
487.2
482.8
482.8
K
+
(meq/l)
12.3
11.6
11.6
S-Mn (meq/l)
0.000
0.011
—
T-Mn (meq/l)
0.000
0.013
0.196
S-Fe (meq/l)
0.005
0.027
—
T-Fe (meq/l)
0.426
0.423
0.651
Cl
−
(meq/l)
552.9
507.7
507.7
NO
3
-N (meq/l)
0.004
0.001
0.001
S-TOC (meq/l)
0.056
0.333
0.008
