II. Assignment of model parameters
This numerical simulation only considers the convection and dispersion of pollutants in the groundwater environment, so the parameter assignment only considers
the permeability coefficient, dispersion and porosity. The aquifer permeability
coefficient is 0.1 m/d according to the calculation results of the infiltration test, and
the longitudinal dispersion coefficient, lateral dispersion coefficient and porosity of
the aquifer are 0.1 m, 0.035 m and 0.45 m respectively according to the dispersion
test results. We aim to briefly analyze the capture of the particular pollutant Pb by
the existing groundwater monitoring, showcase and demonstrate the effectiveness
and rationality of existing monitoring wells, and therefore no parameter calibration
has been done.
III. Treatment of definite solution conditions
The model is set as a steady flow field with a constant head as its boundary, as
shown in Fig. 5.82. According to 1.25% hydraulic gradient of the target aquifer, the
heads at the west and east boundaries are 40 m and 30 m respectively.
According to the analysis of the Environmental Impact Statement of the Beijing
Centralized Hazardous Waste Disposal Center, the source intensity of Pb is
1.75 mg/L after the leachate from the rigid landfill pit is mixed with groundwater.
In this study, Pb is the particular pollutant. For two scenarios shown in Fig. 5.83
(there is one 10 m  20 m point of failure in the middle of the eastern side and
western side of the rigid landfill pit respectively) and Fig. 5.84 (there are three
10 m  20 m points of failure at the eastern side and western side of the rigid
landfill pit), the pollution plume range of the particular pollutant Pb is calculated
and analyzed under the condition of steady flow and constant concentration after the
leachate and groundwater are mixed for 1a, 5a, 10a and 15a (Fig. 5.85).
④ Analysis of rationality and effectiveness of monitoring wells
For Scenario 1, there is one 10 m  20 m point of failure in the middle of the
eastern side and western side of the rigid landfill pit respectively. The pollution
plume ranges (W  L) of the particular pollutant Pb are 31 m  36 m, 37 m
41 m, 37 m  50 m and 37 m  56 m after the particular pollutant Pb is mixed
with the groundwater in the target aquifer and exists as a pollution source with the
source intensity of 1.75 mg/L for 1st, 5a, 10a and 15a. Under Scenario 1, none of
the above three pollution monitoring wells arranged around the rigid landfill pit can
capture leakage information.
For Scenario 2, there are three 10 m  20 m points of failure uniformly distributed on the western and eastern sides of the rigid landfill pit. The pollution
plume ranges (W  L) of the particular pollutant Pb are 31 m  36 m, 37 m
41 m, 37 m  50 m and 37 m  56 m after the particular pollutant Pb is mixed
with the groundwater in the target aquifer and exists as a pollution source with the
source intensity of 1.75 mg/L for 1st, 5a, 10a and 15a. Under Scenario 2, one
pollution monitoring well arranged on the western side of the southern end of the
316
5 Application Cases
This numerical simulation only considers the convection and dispersion of pollutants in the groundwater environment, so the parameter assignment only considers
the permeability coefficient, dispersion and porosity. The aquifer permeability
coefficient is 0.1 m/d according to the calculation results of the infiltration test, and
the longitudinal dispersion coefficient, lateral dispersion coefficient and porosity of
the aquifer are 0.1 m, 0.035 m and 0.45 m respectively according to the dispersion
test results. We aim to briefly analyze the capture of the particular pollutant Pb by
the existing groundwater monitoring, showcase and demonstrate the effectiveness
and rationality of existing monitoring wells, and therefore no parameter calibration
has been done.
III. Treatment of definite solution conditions
The model is set as a steady flow field with a constant head as its boundary, as
shown in Fig. 5.82. According to 1.25% hydraulic gradient of the target aquifer, the
heads at the west and east boundaries are 40 m and 30 m respectively.
According to the analysis of the Environmental Impact Statement of the Beijing
Centralized Hazardous Waste Disposal Center, the source intensity of Pb is
1.75 mg/L after the leachate from the rigid landfill pit is mixed with groundwater.
In this study, Pb is the particular pollutant. For two scenarios shown in Fig. 5.83
(there is one 10 m  20 m point of failure in the middle of the eastern side and
western side of the rigid landfill pit respectively) and Fig. 5.84 (there are three
10 m  20 m points of failure at the eastern side and western side of the rigid
landfill pit), the pollution plume range of the particular pollutant Pb is calculated
and analyzed under the condition of steady flow and constant concentration after the
leachate and groundwater are mixed for 1a, 5a, 10a and 15a (Fig. 5.85).
④ Analysis of rationality and effectiveness of monitoring wells
For Scenario 1, there is one 10 m  20 m point of failure in the middle of the
eastern side and western side of the rigid landfill pit respectively. The pollution
plume ranges (W  L) of the particular pollutant Pb are 31 m  36 m, 37 m
41 m, 37 m  50 m and 37 m  56 m after the particular pollutant Pb is mixed
with the groundwater in the target aquifer and exists as a pollution source with the
source intensity of 1.75 mg/L for 1st, 5a, 10a and 15a. Under Scenario 1, none of
the above three pollution monitoring wells arranged around the rigid landfill pit can
capture leakage information.
For Scenario 2, there are three 10 m  20 m points of failure uniformly distributed on the western and eastern sides of the rigid landfill pit. The pollution
plume ranges (W  L) of the particular pollutant Pb are 31 m  36 m, 37 m
41 m, 37 m  50 m and 37 m  56 m after the particular pollutant Pb is mixed
with the groundwater in the target aquifer and exists as a pollution source with the
source intensity of 1.75 mg/L for 1st, 5a, 10a and 15a. Under Scenario 2, one
pollution monitoring well arranged on the western side of the southern end of the
316
5 Application Cases