Contaminant Fate and Reactive Transport in Groundwater - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 881

Fig. 19.16 Best fitting results of 2D reactive transport modeling for the Osterhofen site compared
to the concentration of 1.5 mg/L measured at 450 m distance
19.6 Summary and Conclusions
This chapter presents the basic theory on contaminant transport, including a descrip-
tion of the principal physical and biogeochemical processes that determine the
formation and migration of contaminant plumes in groundwater. Moreover, an intro-
duction to contaminant transport models and their application is given in order to
familiarize the reader with the fundamental tools for the quantitative description of
the fate and transport of contaminants in aquifer systems. The discussion is com-
plemented with two practical examples concerning the reactive transport of toluene
from a LNAPL source and the transport and degradation of ammonium in a landfill
leachate plume.
Despite considerable advances in the last three decades in both process under-
standing and numerical modeling techniques (e.g. improved numerical algorithms
and availability of larger computational resources), additional effort is needed in
order to fill still existing knowledge gaps and to make progress in our capability
to understand and rigorously describe the complex natural processes that deter-
mine contaminant transport in natural formations. In the opinion of the authors,
active and promising research fields are the investigation of diffusive/dispersive
mixing processes in groundwater and their impact on mixing-controlled reactions
in homogeneous and heterogeneous formations, together with an improved knowl-
edge and capability of quantitatively describe the impact of the activity of microbial
communities on contaminant transport and degradation.
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