US 5,013,185 A · Multi-shaft auger apparatus and process for fixation of soils containing toxic wastes

Abstract

The present invention is directed to a modified multishaft auger apparatus for in situ fixation of soil contaminated with toxic waste. Soil fixation is achieved by augering a plurality of boreholes downwardly into the contaminated soil with a modified multi-shaft auger machine. A chemical hardener is injected into the contaminated soil while the boreholes are being augered. As the shafts rotate, a plurality of soil mixing paddles extending outwardly from each shaft blend the contaminated soil with the chemical hardener in situ. The soil mixing paddles are configured so as to minimize the vertical movement of the contaminated soil out of the boreholes in order to maximize in situ containment of the contaminated soil. Upon hardening, the soil is immobilized such that hazardous chemicals, toxic compounds and other soil constituents are trapped in order to prevent migration from the fixated area. A multi-shaft auger apparatus capable of augering boreholes of different diameter is disclosed. Boreholes of different diameter are arranged in a pattern which efficiently eliminates interstitial spaces between adjacent boreholes. As a result, a larger area of contaminated soil may be fixated according to the methods of the present invention more efficiently than by use of boreholes having substantially equal diameter. To achieve maximum horizontal blending of the contaminated soil with the chemical hardener, various soil mixing paddle configurations are disclosed. The present invention contemplates the use of different soil mixing paddle configurations depending upon the existing soil conditions.

Claims56

Dependent claims

A method for in situ fixation of soil contaminated with toxic wastes using a multi-shaft auger apparatus, the method comprising the steps of:

(a) augering a plurality of boreholes downwardly into the contaminated soil with an auger apparatus having a plurality of shafts, each shaft having penetrating means at a lower end of the shaft and a plurality of soil mixing paddles extending outwardly from the shaft;
(b) injecting a chemical hardener into the contaminated soil during the augering of the boreholes;
(c) blending the contaminated soil and the chemical hardener in situ with the soil mixing paddles to form a soil/hardener mixture, said blending process minimizing the vertical movement of the contaminated soil out of the boreholes in order to maximize in situ containment of the contaminated soil;
(d) withdrawing the multi-shaft auger apparatus from the contaminated soil;
and
(e) allowing the soil/hardener mixture to cure to form a hardened column in the borehole, thereby fixating the contaminated soil.

3 more elements

A method for in situ fixation soil contaminated with toxic wastes using a multi-shaft auger apparatus, the method comprising the steps of:

(a) augering a plurality of boreholes downwardly into the contaminated soil with an auger apparatus having a plurality of substantially parallel and coplanar shafts, said shafts defining a geometric soil mixing plane, each of the shafts having a penetrating auger at a lower end, means for rotating the shaft at an upper end of the shaft, and a plurality of soil mixing paddles extending outwardly from the shaft and positioned between the upper and lower ends of the shaft;
(b) injecting a chemical hardener into the contaminated soil during the augering of the boreholes;
(c) blending the contaminated soil and the chemical hardener in situ with the soil mixing paddles to form a soil/hardener mixture, said blending process minimizing the vertical movement of the contaminated soil out of the boreholes in order to maximize in situ containment of the contaminated soil;
(d) withdrawing the multi-shaft auger apparatus from the contaminated soil;
(e) moving the multi-shaft auger apparatus to a position such that the shafts are adjacent to previously augered boreholes;
(f) repeating the augering, injecting, blending, withdrawing, and moving steps (a) through (e) in the contaminated soil adjacent to the previously augered boreholes containing the soil/hardener mixture, thereby fixating the adjacent contaminated soil in the soil/hardener mixture;
and
(g) allowing the soil/hardener mixture to cure to form a hardened mass in which the contaminated soil is fixated.

5 more elements

A method for in situ fixation of soil contaminated with toxic wastes using a two-shaft auger apparatus, the method comprising the steps of:

(a) augering two boreholes downwardly into the contaminated soil with an auger apparatus having two substantially parallel and coplanar shafts, said shafts defining a geometric soil mixing plane, each of the shafts having a penetrating auger at a lower end, means for rotating the shaft at an upper end of the shaft, and a plurality of soil mixing paddles extending outwardly from the shaft and positioned between the upper and lower ends of the shaft;
(b) injecting a chemical hardener into the soil during the augering of the borehole;
(c) blending the contaminated soil and the chemical hardener in situ with the soil mixing paddles to form a soil/hardener mixture, said blending process minimizing the vertical movement of the contaminated soil out of the boreholes in order to maximize in situ containment of the contaminated soil;
(d) withdrawing the two-shaft auger apparatus from the contaminated soil;
(e) moving the multi-shaft auger apparatus to a position such that the shafts are adjacent to previously augered boreholes;
(f) repeating the augering, injecting, blending, withdrawing, and moving steps (a) through (e) in the contaminated soil adjacent to the previously augered boreholes containing the soil/hardener mixture, in a manner such that the interstitial spaces between the adjacent boreholes are minimized and that substantially all of the contaminated soil between the boreholes is blended with the chemical hardener;
and
(g) allowing the soil/hardener mixture to cure to form a hardened mass in which the contaminated soil is fixated.

5 more elements

A method for in situ fixation of soil contaminated with toxic wastes using a three-shaft auger apparatus, the method comprising the steps of:

(a) augering three boreholes downwardly into the contaminated soil with an auger apparatus having three substantially parallel and coplanar shafts, said shafts defining a geometric soil mixing plane, each of the shafts having a penetrating auger at a lower end, means for rotating the shaft at an upper end of the shaft, and a plurality of soil mixing paddles extending outwardly from the shaft and positioned between the upper and lower ends of the shaft;
(b) injecting a chemical hardener into the soil during the augering of the boreholes;
(c) blending the contaminated soil and the chemical hardener in situ with the soil mixing paddles to form a soil/hardener mixture, said blending process minimizing the vertical movement of the contaminated soil out of the boreholes in order to maximize in situ containment of the contaminated soil;
(d) withdrawing the three-shaft auger apparatus from the contaminated soil;
(e) moving the three-shaft auger apparatus to a position such that the shafts are adjacent to previously augered boreholes;
(f) repeating the augering, injecting, blending, withdrawing, and moving steps (a) through (e) in the contaminated soil adjacent to the previously augered boreholes containing the soil/hardener mixture, in a manner such that the interstitial spaces between the adjacent boreholes are minimized and that substantially all of the contaminated soil between the boreholes is blended with the chemical hardener;
and
(g) allowing the soil/hardener mixture to cure to form a hardened mass in which the contaminated soil is fixated.

5 more elements

Dependencies are inferred from the claim text.

Multi-shaft auger apparatus and process for fixation of soils containing toxic wastes

Life of this patent

Multi-shaft auger apparatus and process for fixation of soils containing toxic wastes

Life of this patent

Abstract

Claims56