Soil flushing, in situ

There are a number of critical parameters to be considered for the application of in situ soil flushing, including the hydrogeological conditions of the contaminated site, the type and properties of contaminants, the properties of the additives, and the treatability of the flushing solution.76 80... 

For in situ soil flushing, large volumes of water, at times supplemented with surfactants, cosolvents, or treatment compounds, are applied to the soil or injected into the groundwater to raise the water table into the contaminated soil zone. Injected water and treatment agents are isolated within the underlying aquifer and recovered together with flushed contaminants.50-52,85... 

There are various agents that can be used to wash soil and drive its contaminants out, as discussed in the section on in situ soil flushing technology. 

The excavated soil is removed from the site and screened to remove large solid objects. The screened soil is washed and the washing water is treated.78 Clearly, the washing media used in in situ soil-flushing treatment can be used here. The most common washing medium is water. Surfactants are used to reduce the affinity of contaminants to the soil. 

L. Di Palma, Experimental Assessment of a Process for the Remediation of Organophosphorous Pesticides Contaminated Soils Through In situ Soil Flushing and Hydrolysis, Water Air Soil Pollut. 143(1 ), 301-314, Feb. (2003). 

Badr, Hanna, and de Brauer, 2004), thereby overcoming the mass-transfer limitation of the biodegradation process and the desorption stage of in situ soil flushing. 

In situ soil remediation with physical methods includes the in situ heating (in situ thermal treatment), ground-freezing, hydraulic fracturing, immobilization/stabilization, flushing, chemical detoxification, vapor extraction, steam extraction, biodegradation/bioremediation, electroosmosis/ electrokinetic processes, etc. 

Wayt, H.J. Wilson, D.J. Soil clean-up by in-situ surfactant flushing II theory of miscellar solubilization. Separ. Sci. Technol. 1989, 24, 905-907. 

Gannon OK (1988) PhD Environmental reclamation through use of colloidal foam flotation, in-situ soil aeration and in-situ surfactant flushing, UMI Disseration Services Order Number 8910849... 

The applicability of solvent flushing, however, is often limited by the characteristics of the soil, especially the particle size distribution. While sandy soils may result in xmcon-trolled fluid migration, clayey soils with partieles size less than 60 pm are often considered unsuitable for in-situ solvent flushing due to low soil permeability. In an attempt to remove PAHs from poorly permeable soils, Li, et alP investigated the possibility of combining cosolvent flushing with the electrokinetie technique. Electrokinetic remediation... 

Surfactant washing is among the most promising in situ chemical treatment methods. Surfactants can improve the solvent property of the flushing water, emulsify nonsoluble organics, and enhance the removal of hydrophobic organics sorbed onto soil particles. 

The big difference in application from the in situ flushing method is that this ex situ method can apply to soils with lower permeability, because soil is excavated and can be sufficiently washed. The following presents two ex situ soil washing processes for organic contaminants the BioGenesis soil cleaning process and the BioTrol soil washing system. 

Soil treatment, 25 834-843, 843-845 bioremediation, 25 835-836 electrokinetics, 25 843-844 ex situ bioremediation, 25 836, 842-843 in situ air stripping, 25 844 in situ bioremediation, 25 836-842 plume containment, 25 835 soil flushing, 25 844 soil vapor extraction, 25 844 sulfur use in, 23 591 vitrification, 25 844-845 Soil-vapor extraction defined, 3 759t... 

Cosolvent flushing is an in situ technology that enhances the remediation of contaminated soils and groundwater by injecting water and a cosolvent such as alcohol (e.g., ethanol, methanol, and isopropyl) into a contaminated area. Research has shown that an organic cosolvent can also accelerate the movement of metals through a soil matrix. The alcohol causes both an increase in aqueous contaminant solubility and lowering of non-aqueous-phase liquid (NAPL)-water interfacial tension. 

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