Groundwater migration, barrier

The technology can be nsed for the passive in sitn treatment of groundwater via exchangeable filter socks placed in trenches or wells, or via a cement slnrry injected into the aquifer to form a migration barrier across the plnme of contamination, or as a sonrce control. OCR can also be used in powder form for the in sitn or ex situ treatment of soils. The primary in sitn soil application is the treatment of nndergronnd storage tank (UST) removal excavations. The technology can also be nsed to treat soils in ex sitn biopiles. 

The Arctic Foundations, Inc. (AFl), frozen soil barrier technology is constructed by artificially freezing the soil pore water. As the pore water freezes, the soil permeability decreases, thereby forming an impermeable barrier that surrounds and contains the contaminants. When properly installed, the frozen soil barrier prevents the migration of contaminants within groundwater and soil. Contaminants are contained in situ, with the frozen native soils serving as the containment medium. The contaminants are isolated by the wall until appropriate remediation techniques can be applied. 

Studies are being conducted by the Pacific Northwest National Laboratory (PNNL) to investigate the use of clinoptilolite as an in situ permeable barrier to strontium (Sr °) migration in groundwater at the site referred to as the 100-N area of the Hanford Site. This technology uses clinoptilolite to absorb radioactive Sr ° from groundwater. 

The transport process from the repository is schematically illustrated in Figure 3. Radionuclides and corrosion products would diffuse from the canister into the groundwater, and the migration will then be retarded first in the backfill barrier and after that in the bedrock. 

In a heterogeneous basin, in a carrier rock with groundwater flow parallel to the inclined upper boundary of the rock, the updip migration of a hydrocarbon stringer of length t accumulated along the carrier rock - barrier rock interface will start if... 

Contaminants may migrate within saturated residual or transported soils, within soil macropores, or within small interconnected pores where they find their way into groundwater. In either case contaminant dispersal will be limited to distinct groundwater subbasins defined by fixed or transient groundwater divides, by the hydraulic-head distribution within the flow system, and by geological barriers which restrict flow such as the presence of poorly permeable soil or bedrock units. 

Installation of low permeability barriers to reduce migration of soil vapours and contaminated groundwater Removes VOCs from soil atmosphere by vacuum pumping and encourages further volatilisation from soil particles and groundwater surface... 

Reactive barriers or in situ reactors Groundwater Introduction of reagents into the ground to treat contaminated plume as it migrates through the barrier or treatment zone (includes bioremediation of groundwater)... 

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