| Summary: | This research focuses on hydrogeological factors controlling groundwater
contaminant movement from the landfill site. The objectives of this study were to
provide an understanding of the local hydrogeological conditions which influence
to contaminant transport. In other hand, the providing of understanding on
geochemical, biogeochemical processes must be analyzed which control the
concentration of contaminants concentration.
This research was applied an analytical method model for one-dimensional
solute transport, a two dimensional solute transport numerical model. Finite
difference method was used to solve the partial differential equations of flow and
transport. Method of characteristic (MOC) was applied to solve the advection part
of the solute transport equation. On other hand, the growth of heterotrophic
bacteria under aerobic and anaerobic conditions was considered in the two
dimensional bacteria mediated reduction model in which the advection part of the
solute transport was solved by method of characteristics (MOC) while the rest of
processes including reaction terms were solved by finite difference method.
Switching function and inhibition coefficients were used to control the sequence
of reduction reactions. The bacterial growth was formulated by the double Monod
kinetic equation. Three bacteria (X1, X2, and X3) groups were defined in the redox
model.
The two dimensional vertical groundwater flow simulation is to show the
movement of the groundwater flow system. The two permeability values show
that flow velocity (Darcy�s velocity) depends on permeability of lithology and
hydraulic gradient. K1 is higher than K2, thus the flow velocity in K2 zone is lower
than K1 zone. And the flows from K1 to K2 slowly which move angled direction,
this step applied a two-dimensional vertical flow numerical model. At the second
step, the solute transport model is to show the analysis of plume of solute
transport. The plume was influenced by water flow movement in subsurface.
Advection and dispersion are sufficiently slow and mechanisms for adsorption are
sufficiently effect lead migration to groundwater. Lead introduced into the
groundwater near Piyungan landfill rapidly and completely attenuated.
In the last step of this research the growth of heterotrophic bacteria under
aerobic and anaerobic conditions was considered in the two dimensional bacteria
mediated reduction model which was applied in the present study. The model
parameters applied in the simulation were obtained from field observations,
literature review and tuning by trial and error method.
seen on the reduced environment between 0-0.7 m. The oxygen (O2) on surface
can move downward by infiltrated water as 8 mg/L, and CH2O from mobile phase
which supports bacteria X1 to grow in freshwater CH2O was considered as the
electron
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