In-situ restoration of contaminated soils and groundwater using calcium chloride
First Claim
1. A method for stabilizing in-situ soluble, heavy metal, anionic and/or cationic contaminants in carbonate-containing land or submarine formations which comprises the steps of:
- introducing into the carbonate-containing formation an aqueous solution of calcium chloride, said solution containing a stabilizing amount of calcium ions;
wherein the contaminants and the carbonate when subjected to calcium ions form coprecipitates which are substantially insoluble in formation fluids, thereby inhibiting the remobilization of said heavy metal contaminants by groundwater.
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Abstract
A method for stabilizing in-situ soluble heavy metal contaminants in carbonate-containing land or submarine formations which comprises introducing into the carbonate-containing formation an aqueous solution of calcium chloride, wherein the solution contains a stabilizing amount of calcium ions. The contaminants and the carbonate form coprecipitates with the calcium ions which are insoluble in formation fluids, therefore substantially inhibiting the remobilization of the heavy metals with groundwater. The method is effective with heavy metals which exist in both anionic and cationic form in carbonate-containing land or submarine formations. The method may be used to treat land formations hundreds of feet below the surface, landfill deposits, or submarine formations to reduce soluble heavy metal contaminants to a few parts per million.
34 Citations
20 Claims
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1. A method for stabilizing in-situ soluble, heavy metal, anionic and/or cationic contaminants in carbonate-containing land or submarine formations which comprises the steps of:
introducing into the carbonate-containing formation an aqueous solution of calcium chloride, said solution containing a stabilizing amount of calcium ions; wherein the contaminants and the carbonate when subjected to calcium ions form coprecipitates which are substantially insoluble in formation fluids, thereby inhibiting the remobilization of said heavy metal contaminants by groundwater. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for stabilizing in-situ soluble, heavy metal, anionic and/or cationic contaminants in land or submarine formations that lack carbonate, said method comprising the steps of:
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a) introducing into the formation an aqueous solution of calcium chloride, said solution containing a stabilizing amount of calcium ions; and b) introducing carbon dioxide into the formation; wherein said contaminants when subjected to calcium ions and carbonate form coprecipitates which are substantially insoluble in formation fluids, thereby inhibiting the remobilization of said heavy metal contaminants by groundwater. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for stabilizing in-situ soluble, heavy metal, anionic and/or cationic contaminants in land or submarine formations that contain little or no carbonate, said method comprising the steps of:
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a) first introducing into the formation an aqueous solution of calcium chloride containing about 1 to about 5 gm/liter of calcium chloride; and b) then introducing carbon dioxide into the formation; wherein said contaminants when subjected to calcium ions and carbonate form coprecipitates which are substantially insoluble in formation fluids, thereby inhibiting the remobilization of said heavy metal contaminants by groundwater.
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Specification