PROBLEM TO BE SOLVED: To break air bubbles contained in excavated soil without using a deforming agent and to prevent a surfactant, which is used as a material of such air bublles, from being diffused in the environment. SOLUTION: In a method for treating a surfactant in excavated soil, the excavated soil is discharged from a chamber 6 of a shield machine 5 with a screw conveyor 1 communicatively connected with the chamber (step 101); the soil is then conveyed to a line mixer 2 disposed on the discharge side of the screw conveyor and activated carbon charged into the line mixer 2 is added to the excavated soil to prepare soil to be treated (step 102); the soil to be treated is stirred for mixing in the line mixer 2 to uniformly disperse the activated carbon in the soil to be treated (step 103); and the soil that has gone through the activated-carbon treatment is taken out behind the shield machine 5 with a belt conveyor 4 disposed downstream of the line mixer 2 (step 104). COPYRIGHT: (C)2012,JPO&INPIT
