Soil and/or groundwater remediation process

Abstract

A method of treating contaminants in soil and/or groundwater comprising adding a source of an oxidizing agent and an aqueous solution of a metal catalyst having a pH of from about 5 to 8 to the in situ environment in amounts capable of producing reactive species sufficient to oxidize at least one of the contaminants.

What is claimed is:  
     
         1 . A reagent for use in the treatment of contaminants in an in situ environment, comprising: 
 an aqueous solution comprising an effective amount of a metal catalyst selected from at least one member of the group consisting of Fe (II) salts, Fe (III) salts, Fe (II) chelates, Fe (III) chelates and combinations thereof; and    an optional pH modifying agent in an amount sufficient to provide a pH for said reagent in the range of from about 5 to 8.    
     
     
         2 . The reagent of  claim 1  wherein the pH modifying agent is selected from water and abase.  
     
     
         3 . The reagent of  claim 1  wherein said metal catalyst is Fe (II) or Fe (III) sulfate.  
     
     
         4 . The reagent of  claim 1  wherein the metal catalyst is Fe (II) or (III) EDTA chelate.  
     
     
         5 . The reagent of  claim 2  wherein the pH modifying agent is water.  
     
     
         6 . The reagent of  claim 2  wherein the pH modifying agent is sodium hydroxide.  
     
     
         7 . A method of treating contaminants in an in situ environment, comprising: 
 preparing an aqueous solution comprising an effective amount of a metal catalyst selected from at least one member of the group consisting of Fe (II) salts, Fe (III) salts, Fe (II) chelates, Fe (III) chelates and combinations thereof;    optionally adding a pH modifying agent to said aqueous solution in an amount sufficient to provide a pH for said reagent in the range of from about 5 to 8;    adding a source of an oxidizing agent to said in situ environment in an amount sufficient to treat said contaminants; and    adding said aqueous catalyst solution to said in situ environment in the presence of said source of the oxidizing agent in an amount sufficient to promote the formation of the oxidizing agent in an amount sufficient to treat said contaminants.    
     
     
         8 . The method of  claim 7  wherein said source of the oxidizing agent is a peroxide.  
     
     
         9 . The method of  claim 7  wherein the pH modifying agent is selected from water and a base.  
     
     
         10 . The method of  claim 8  wherein the source of the peroxide is selected from the group consisting hydrogen peroxide, sodium peroxide and calcium peroxide.  
     
     
         11 . The method of  claim 10  wherein the source of the peroxide is hydrogen peroxide.  
     
     
         12 . The method of  claim 7  further comprising stabilizing said source of the oxidizing agent.  
     
     
         13 . The method of  claim 12  comprising stabilizing the source of the peroxide with a stabilizer selected from the group consisting of acids, salts, and mixtures thereof.  
     
     
         14 . The method of  claim 13  wherein the stabilizer is selected from the group consisting of phosphoric acid, monopotassium phosphate and combinations thereof.  
     
     
         15 . The method of  claim 7  comprising alternately adding the source of the oxidizing agent and the aqueous catalyst solution to the in situ environment.  
     
     
         16 . The method of  claim 7  comprising continuously adding the oxidizing agent and the aqueous catalyst solution to the in situ environment.  
     
     
         17 . The method of  claim 15  wherein the aqueous catalyst solution is first added to the in situ followed by source of the oxidizing agent.  
     
     
         18 . The method of  claim 15  wherein source of the oxidizing agent is first added followed by said aqueous catalyst solution.  
     
     
         19 . The method of  claim 16  wherein the aqueous catalyst solution is first added to the in situ environment followed by source of the oxidizing agent.  
     
     
         20 . The method of  claim 16  wherein source of the oxidizing agent is first added to the in situ environment followed by said aqueous catalyst solution.  
     
     
         21 . The method of  claim 1  wherein the in situ environment comprises at least one of soils and groundwater with moderate to high permeability.  
     
     
         22 . The method of  claim 1  wherein the in situ environment comprises at least one of soils and groundwater with low to moderate permeability.  
     
     
         23 . The method of  claim 7  wherein at least a portion of the oxidizing agent comprises hydroxyl radicals.  
     
     
         24 . The method of  claim 7  wherein the in situ environment is selected from the group consisting of soil, groundwater, and fractured bedrock.  
     
     
         25 . The method of  claim 7  wherein the steps of adding the source of the oxidizing agent and the aqueous catalyst solution are made at an elevated pressure.  
     
     
         26 . The method of  claim 25  wherein the elevated pressure is from about 20 to 100 psi.  
     
     
         27 . The method of  claim 25  wherein the in situ environment is fractured bedrock.  
     
     
         28 . The method of  claim 24  comprising adding the source of the oxidizing agent and the aqueous catalyst solution to a region within the in situ environment known as the capillary fringe.  
     
     
         29 . The method of  claim 28  wherein the contaminants to be treated are less dense than water.  
     
     
         30 . The method of  claim 24  comprising adding the source of the oxidizing agent and the aqueous catalyst solution to a region of the in situ environment comprising the lower layers of the saturated zone.  
     
     
         31 . The method of  claim 30  wherein the contaminants are denser than water.  
     
     
         32 . The method of  claim 30  comprising adding the source of the oxidizing agent and the aqueous catalyst solution to the lower layers of the saturated zone at different depths when the depth of the lower layer of the saturated zone is greater than 20 feet.  
     
     
         33 . The method of  claim 32  further comprising adding multiple doses of the source of the oxidizing agent and the aqueous catalyst solution.  
     
     
         34 . The method of  claim 32  wherein the difference in depth of each dose is in the range of from about 5-10 feet.  
     
     
         35 . The method of  claim 7  wherein the source of oxidizing agent is peroxide in water at concentration of up to 35% by weight.  
     
     
         36 . The method of  claim 35  wherein the preferred concentration of the source of the oxidizing agent is less than 10%.