CLEANING OF EXCAVATED SOIL CONTAMINATED WITH HAZARDOUS ORGANIC-COMPOUNDS BY WASHING

Bench-scale experiments were conducted to investigate the effectivenes s of an extraction and washing technique for the cleanup of contaminat ed soil using surfactants. The organics studied as model contaminants were 1,2,4-trichlorobenzene (TCB), aniline, phenol, and 2,4-dichloroph enol (DCP). A sandy loam was used as a model field soil. The results d emonstrated the effectiveness of the extraction and washing process fo r decontamination of the sandy loam soil. As much as 99% of the organi c contaminants studied were removed by the process depending upon the compound and the number of washes and rinses. The hydrophilic compound s-aniline, DCP, and phenol-were removed effectively from the soil by w ashing with deionized water alone. Surfactant washing had no advantage over water washing for these compounds. For the removal of TCB, a com bination of washing with surfactant and rinsing with water was require d. Alum coagulation was effective in separating clay and colloidal par ticles from the wash liquid but a relatively high alum dose was requir ed and was observed to enhance adsorption of the contaminants on the c lay particles. A small residual contaminant concentration remained in the soil.