METHOD OF CONCENTRATING CONTAMINANT IN SOIL

PURPOSE: To cause an electroendosmosis phenomenon to effectively concentrate contaminant without injecting water in a moisture unsaturated zone above the level of the underground water by freezing soil from the periphery of a cathode and also giving potential difference between the cathode and an anode. CONSTITUTION: In a concentrator, first when a refrigerator 2 is operated to feed brine into a freezing pipe 1, soil is frozen from the part in contact with the outer peripheral surface of the freezing pipe 1 to concentrically grow frozen soil. Next, when a DC power source 4 is operated to give potential difference to between the freezing pipe 1 and an electrode bar 3, contaminant concentrated in nonfrozen water by freezing begins to move toward the freezing pipe 1 which is a cathode together with the nonfrozen water by an electroendosmosis phenomenon. That is, while the concentration of contaminant in soil is decreased to a desired value, contaminant is gradually accumulated on soil around the freezing pipe 1. Consecutively, soil contg. contaminant of high concentration is excavated and removed after removing the freezing pipe 1.