Permeable Reactive Barriers: Cost-Effective and Sustainable Remediation of Groundwater - Permeable Reactive Barrier: Sustainable Groundwater Remediation - page 6

FIGURE 1.1
Dynamics of fluids in fractured rock. (Photograph by Dr. Jessica Winder.)

the contaminant species may migrate in rock fractures (Figure 1.1). Once dis-
tributed in rock factures, contaminant assessment, delineation, and remedia-
tion become an extremely challenging and expensive process. This is further
constrained by a lack of regulatory policies dealing with endpoints for reme-
diation of such contaminated sites. Often where such sites have been remedi-
ated, rebound from rock fractures has also been a major challenge.
The schematic diagram in Figure 1.2 shows a dense NAPL completely fill-
ing pores in the subsurface soil/groundwater environment and also coating
soil particles, which makes delineation of the contaminant plume challeng-
ing and often very difficult.

DNAPLs completely
filling in pores
Soil particle

DNAPLs coating
soil particles

Soil particle

DNAPL

DNAPL

FIGURE 1.2
Dense nonaqueous phase liquid (DNAPL) interactions with soils in vadose zone.