REMEDIATION OF ORGANICS-CONTAMINATED SANDY SOIL BY IN-SITU WASHING

A new method of in situ soil remediation called in situ washing by sedimentation (IWS) was introduced, by injecting a high air-pressure into a mixture of saturated water-sandy soil and hydraulically separating the soil particles based on their particle size and density. This physical separation exploits the distribution of contaminant in the soil by physically separating a selected contaminant-rich fraction. The effect of soil-water ratio and diameter geometry of the column on the effectiveness of separation by IWS was investigated. Soil-water ratio 1:2 (v/v) was found to be optimum for particle segregation produced by IWS, however, generally the diameter geometry column was not effect on the particle separation. The suitability of IWS for organics remediation was investigated by batch column experiment. The laboratory experiment was effective to produce a distinct size separation of the contaminated soil into the coarse and fine fractions, as well as the wash water, and indicating that a significant reduction in organics contaminant level (90%) may be achieved.