Composition and method for the solidification of toxic or hazardous drilling and agricultural waste

1. A method for solidification of an aqueous waste material containing heavy metals or hazardous organic contaminants comprising mixing a layered phyllosilicate consisting of a water swellable smectite clay, into said aqueous waste material in an amount sufficient to solidify the aqueous waste material sufficiently such that the solidified aqueous waste material has essentially no free liquid, as determined by the solidified aqueous waste material passing the Paint Filter Liquids Test, EPA Method 9095B;

shearing the aqueous waste material, containing said layered phyllosilicate, sufficiently to partially exfoliate the layered phyllosilicate into phyllosilicate platelets and tactoids while in contact with the aqueous waste material; and

pumping the sheared wasted material to a solidification area or transport vehicle for solidification.

2. The method of claim 1 , wherein the aqueous waste material is a drilling fluid waste material or an agricultural waste material, and the water-swellable layered phyllosilicate is mixed into the aqueous waste material in an amount of about 0.1% to about 10% based on the weight of the aqueous waste material.

3. A method for solidification of an aqueous waste material containing heavy metals or hazardous organic contaminants comprising:

adding a layered phyllosilicate to said aqueous waste material in an amount sufficient to solidify the aqueous drilling fluid waste sufficiently, after shearing, such that the solidified aqueous waste material has no free liquid;

shearing the aqueous waste material, containing said layered phyllosilicate, sufficiently to partially exfoliate the layered phyllosilicate into phyllosilicate platelets and tactoids while in contact with the aqueous waste material;

pumping the sheared aqueous waste material and layered phyllosilicate to a solidification area; and

allowing the sheared aqueous waste material and partially exfoliated layered phyllosilicate sufficient time to solidify such that there are no free liquids remaining in the solidified waste material, as determined by the solidified aqueous waste material passing the Paint Filter Liquids Test, EPA Method 9095B.

4. The method of claim 3 further including the step of transporting the solidified waste material in an unsealed transport vehicle to a landfill.

5. The method of claim 4 , wherein the transport vehicle is a dump truck.

6. The method of claim 3 , wherein the aqueous waste material is a drilling fluid waste and the sheared aqueous drilling fluid waste and partially exfoliated layered phyllosilicate is pumped back to the solidification area for solidification.

7. A method for solidification of an aqueous waste material containing heavy metals or hazardous organic contaminants comprising mixing a water-swellable layered phyllosilicate and a superabsorbent polymer into said aqueous waste material in an amount sufficient to solidify the aqueous waste material sufficiently such that the solidified aqueous waste material has essentially no free liquid, as determined by the solidified aqueous waste material passing the Paint Filter Liquids Test, EPA Method 9095B, and shearing the aqueous waste material, containing said water-swellable layered phyllosilicate sufficiently to partially exfoliate the layered phyllosilicate into phyllosilicate platelets and tactoids while in contact with the aqueous waste material.

8. The method of claim 7 , wherein the aqueous waste material is a drilling fluid waste material or an agricultural waste material, and the layered phyllosilicate is mixed into the aqueous waste material in an amount of about 0.1% to about 10% based on the weight of the aqueous waste material and the superabsorbant polymer is added in an amount of about 0.1% to about 10% based on the weight of the aqueous waste material.

9. The method of claim 8 , wherein the superabsorbent polymer is selected from the group consisting of partially crosslinked polyacrylates, starch acrylonitrile graft polymers, carboxymethylcellulose, sulfonated polystyrenes, hydrolyzed polyacrylamides, polyvinyl alcohols, polyethylene oxides, polyvinylpyrrolidones, polyacrylonitriles, and combinations thereof.

10. The method of claim 9 , wherein the superabsorbant polymer is a partially crosslinked polyacrylic acid containing about 50% to about 100% neutralized carboxyl groups.

11. The method of claim 7 , including the steps of pumping an aqueous drilling fluid waste from a drilling fluid holding area;

adding the layered phyllosilicate and superabsorbent polymer to said aqueous drilling fluid waste in an amount sufficient to solidify the aqueous drilling fluid waste sufficiently, after shearing, such that the solidified aqueous drilling fluid waste has no free liquid;

shearing the aqueous drilling fluid waste, containing said layered phyllosilicate and superabsorbent polymer, sufficiently to partially exfoliate the layered phyllosilicate into phyllosilicate platelets and tactoids while in contact with the aqueous drilling fluid waste;

pumping the sheared aqueous drilling fluid waste and layered phyllosilicate to a solidification area; and

allowing the sheared aqueous drilling fluid waste, superabsorbent polymer and partially exfoliated layered phyllosilicate sufficient time to solidify such that there are no free liquids remaining in the solidified drilling fluid waste.

12. The method of claim 11 further including the step of transporting the solidified drilling fluid waste in an unsealed transport vehicle to a landfill.

13. The method of claim 11 , wherein the transport vehicle is a dump truck.

14. The method of claim 11 , wherein the sheared aqueous drilling fluid waste, superabsorbent polymer and partially exfoliated layered phyllosilicate is pumped back to the drilling fluid holding area for solidification.

15. The method of claim 11 , wherein the weight ratio of layered phyllosilicate to superabsorbent polymer is in the range of 0.1 to 10.

16. The method of claim 11 , wherein the superabsorbant polymer is selected from the group consisting of partially crosslinked polyacrylates, starch acrylonitrile graft polymers, carboxymethylcellulose, sulfonated polystyrenes, hydrolyzed polyacrylamides, polyvinyl alcohols, polyethylene oxides, polyvinylpyrrolidones, polyacrylonitriles, and combinations thereof.

17. The method of claim 15 , wherein the superabsorbant polymer is a partially crosslinked polyacrylic acid containing about 50% to about 100% neutralized carboxyl groups.