Enhanced soil washing

Ultrasound-enhanced soil washing is an ex sitn process being researched for use in soil washing remediation. The technology is not yet commercially available. 

ENHANCED SOIL WASHING WITH SURFACTANTS OR OTHER SOLUBILITY ENHANCERS... 

Polyaromatic hydrocarbons absorb strongly to humus and other soil components, rendering these contaminants difficult to remove by thermal, physical, or chemical means, and unavailable for biodegradation. To desorb polyaromatic hydrocarbons from soil, surfactant flooding processes and soil-washing processes or treatments to enhance the biodegradation of polyaromatic hydrocarbons have been considered. 

Sale, T. and Pitts, M., 1989, Chemically Enhanced in Situ Soil Washing In Proceedings of the National Water Well Association and American Petroleum Institute Conference on Petroleum Plydrocarbons and Organic Chemicals in Groundwater Prevention, Detection and Restoration, November, pp. 487-503. 

T0816 TRW Systems Information Technology Group, Microbial Enhanced Recovery T0818 TVIES, Inc., Soil Washing T0829 U.S. Microbics, Inc., Bio-Raptor... 

Enhances the effectiveness of soil washing or filtration techniques by suspension of targeted contaminants in aqueous solutions and subsequent biodegradation. 

ENSR International Group soil cleaning process is an ex situ treatment for soils contaminated with petroleum hydrocarbons. The process uses a combination of soil washing and solvent extraction. Soil washing removes heavy metals and hydrocarbons from coarse soil particles, resulting in a reduced volume of material to be treated by solvent extraction. Solvent extraction uses a chemical additive that enhances the extraction of hydrocarbons from soil particles in an aqueous slurry. 

The application of surfactants can enhance remediation or recovery of contaminants by increasing their mobility and solubility. Surfactants can thus be used to enhance ex situ soil washing, in situsoil flushing, non-aqueous-phase liquid (NAPE) pump-and-treat applications, and in situbiodegradation. Cationic surfactants have been shown to improve the capacity of soil... 

The most successful uses of surfactants to accelerate desorption and enhanced biodegradation has clearly been associated with the soil-washing industry (U.S. EPA, 1989) and bioslurry reactors (Oberbremer et al., 1990 Mueller et al.y 1991b,c). Here too, however, problems have been encountered at the bench-, pilot-, and full-scale levels with inefficient removal of materials from soils and sediments containing appreciable amounts of clay (c. >25%) or organic matter (c. >10%). 

Surfactant-Enhanced In Situ Soils Washing U.S. Air Force, 1987, ESL-TR-87-18 (NTIS). 

The effectiveness of biosurfactants was demonstrated in soil-washing tests using two SOU samples contaminated with PAHs over several decades. Biosurfactants from urban waste compost (cHAL) enhanced PAH desorption from one soil 2-4-fold, relative to SDS. In addition, cHAL showed much less absorption than did SDS (12%-54% vs. 68%-95%). The results indicate that biosurfactants isolated from compost, instead of synthetic surfactants, can be used for soU remediation (Montoneri et af, 2009). 

Jung J, Yang J K, Kim S H and Yang J W (2008), Feasibility of micellar-enhanced ultrafiltration (MEUF) or the heavy metal removal in soil washing effluent . Desalination, 222,202-211. 

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