Process for immobilizing impurities present in silt

Abstract

A process for immobilizing impurities present in silt This invention relates to a process for immobilizing, inactivating and/or neutralizing impurities present in silt, the silt layer being covered with a layer of a material in finely distributed state, after which at least part of the silt layer is worked loose, a hardenable additive composition is injected in the silt layer and is mixed with the silt layer for binding, immobilizing, inactivating and/or neutralizing the impurities in the silt.

1 . A process for immobilizing, inactivating and/or neutralizing impurities present in silt, characterized in that the silt layer is covered with a layer of a material in a finely distributed state, following which at least part of the silt layer is worked loose, a hardenable additive composition is injected in the silt layer and is mixed with the silt layer for binding, immobilizing, inactivating and/or neutralizing the impurities in the silt.  
     
     
         2 . A process according to  claim 1 , characterized in that the additive composition is a hardenable composition that hardens after mixing with the silt layer.  
     
     
         3 . A process according to  claim 1  or  2 , characterized in that at least part of the layer of the finely distributed substance is mixed with the additive composition and hardens together with the silt layer and the additive composition.  
     
     
         4 . A process according to any of claims  1 - 3 , characterized in that the hardenable additive composition is a grout mixture comprising cement.  
     
     
         5 . A process according to  claim 4 , characterized in that the grout mixture comprises several components, and one or several components is injected in the silt layer individually.  
     
     
         6 . A process according to any of  claims 1  to  5 , characterized in that prior to the application of the finely distributed material at least part of the silt layer is removed.  
     
     
         7 . A device for immobilizing, inactivating and/or neutralizing of impurities present in silt, comprising a rotor head, rotating around at least one axle, the rotor head being provided with at least one or several blades for working loose the silt and each blade containing one or several injection openings for injecting, at increased pressure, an additive composition in the silt.  
     
     
         8 . A device according to  claim 7 , characterized in that at least one blade is provided with a plurality of first injection openings for injecting the additive composition in the rotational direction of the axle at a high pressure, of between 50 and 2000 bar, and with second injection openings for injecting the additive composition in a direction opposite to the rotational direction of the axle, at a lower pressure of between 5 and 500 bar.  
     
     
         9 . A device according to  claim 7  or  8 , characterized in that the injection openings are placed at the front of, behind, in the vicinity of or on the end of the blades.  
     
     
         10 . A device according to claim  7 - 9 , characterized in that the injection openings have an adjustable direction of exit, for injecting the additive composition in a position in front of, behind, next to or near the blades.  
     
     
         11 . Device according to any of claims  7 - 10 , characterized in that the rotor head is mounted on a tiltable arm that is movable from and to a fixing point.  
     
     
         12 . Device according to any of claims  7 - 11 , characterized in that the device is mounted on a movable support that is provided with a control system for controlling the movement and the rotation of the arm and the pressure at which the additive composition is injected through the first and second injection openings.  
     
     
         13 . Device according to any of claims  7 - 12 , characterized in that a mixing device is provided, for mixing previously determined quantities of binding agent and water into an additive composition, and means for transporting the additive composition to the injection openings.