Environmental Engineering Reference
In-Depth Information
7.5.2 M
ATHEMATICAL
M
ODELING
Ying (2002) modii ed an existing one-dimensional mathematical model [CTSPAC—Coupled
Transport of Water, Solutes, and Heat in the Soil-Plant-Atmosphere Continuum (Cawi eld et al.,
1990)] to predict the removal of 1,4-dioxane from groundwater and soil. Calibration of the model was
performed by using the hydroponic and soil experimental results of Aitchison et al. (2000). Model
simulations indicated that uptake from soil would be relatively rapid and that 30% of the 1,4-dioxane
mass would be removed within seven days. The modeled distribution of 1,4-dioxane in the various
parts of the plant correlated well with research by others. The i ndings, shown in Figure 7.4, indicate
that 1,4-dioxane was concentrated early into the leaves, and, after seven days, the leaves still contained
the greatest mass, relative to the proportional mass of the various plant parts. The stem contained
some 1,4-dioxane, but the root system held little, if any, at the conclusion of the simulations. Ying
3000
2500
t
= 24 h
2000
1500
1000
500
0
1
2
3
4
5
6
7
8
9
3000
2500
t
= 72 h
2000
1500
1000
500
0
1
2
3
4
5
6
7
8
9
3000
2500
t
= 168 h
2000
1500
1000
500
0
1
2
3
4
5
6
7
8
9
Stem
comp.
Leaf comp.
Root comp.
FIGURE 7.4
1,4-Dioxane concentration in plant compartments (“Comp.”) at times of 24, 72, and 168 h.
[From Ying, O.Y., 2002,
Journal of Hydrology
266(1-2): 66-82.]
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