Method and apparatus for in-situ chemical oxidation for soil and groundwater remediation

Abstract

A method for treating groundwater and soil with a chemical oxidant, such as potassium permanganate, is provided. A chemical is placed in a powdered or pellet form into injection wells. Baffles are inserted into the ground to direct groundwater flow toward the injection wells. The groundwater flows through the injection wells to pick up the chemical oxidant. A second set of baffles are placed between the injection wells and the contaminated zone to disperse the chemical oxidant laden water. The chemical oxidant laden water flows through the contaminated field, the oxidant acting on the contaminated soil and groundwater to treat same. The injection wells can be pressurized to increase groundwater flow. Tests can be conducted on the other side of the contaminated field to measure the effectiveness of the treatment.

What is claimed is:  
     
         1 . A method for treating a contaminated site including soil and groundwater comprising: 
 providing one or more injection wells located upstream of the contaminated site in the flow of groundwater to the contaminated site;    directing groundwater to flow through the one or more injection wells prior to flowing through the contaminated site;    dissolving a chemical oxidant in the groundwater as the groundwater flows through the one or more injection wells;    dispersing the groundwater with dissolved chemical oxidant for flow through the contaminated field; and    allowing the ground water with the dissolved chemical oxidant to flow through the contaminated field, the dissolved chemical oxidant reacting with and treating the contaminated site.    
     
     
         2 . The method of  claim 1  wherein the chemical oxidant is potassium permanganate.  
     
     
         3 . The method of  claim 1  wherein the step of directing the water to flow through the injection wells comprises installing first baffles upstream of the one or more injection wells.  
     
     
         4 . The method of  claim 3  wherein the first baffles are angled to direct groundwater flow through the one or more injection wells.  
     
     
         5 . The method of  claim 1  further comprising monitoring the treatment by testing groundwater downstream of the contaminated site.  
     
     
         6 . The method of  claim 1  wherein the step of dispersing the groundwater with dissolved chemical oxidant comprises installing second baffles between the one or more wells and the contaminated site for dispersing water.  
     
     
         7 . The method of  claim 6  wherein the second baffles are oriented perpendicular to the direction of groundwater flow.  
     
     
         8 . The method of  claim 1  further comprising increasing groundwater flow from the one or more wells by pressurizing the one or more wells.  
     
     
         9 . The method of  claim 8  wherein the one ore more wells are pressurized by injecting air into the wells.  
     
     
         10 . The method of  claim 8  wherein the one or more wells are pressurized by injecting water into the one or more wells.  
     
     
         11 . An apparatus for treating a contaminated site including soil and groundwater comprising: 
 at least one injection well positioned upstream of the contaminated site;    a chemical oxidant injected within the at least one injection well;    means for directing groundwater to flow through the at least one injection well to pick up the chemical oxidant; and    means for dispersing the groundwater with chemical oxidant to flow through contaminated site.    
     
     
         12 . The apparatus of  claim 11  wherein the chemical oxidant comprises potassium permanganate.  
     
     
         13 . The apparatus of  claim 12  wherein the chemical oxidant comprises pellets.  
     
     
         14 . The apparatus of  claim 12  wherein the chemical oxidant comprises powder.  
     
     
         15 . The apparatus of  claim 11  wherein the means for directing groundwater flow through the at least one injection well comprises first baffles positioned upstream from the wells to funnel groundwater flow into the wells.  
     
     
         16 . The apparatus of  claim 15  wherein the means for dispersing the groundwater comprises second baffles positioned in the ground between the wells and the contaminated site.  
     
     
         17 . The apparatus of  claim 16  wherein the second baffles are positioned perpendicular to the flow of groundwater.  
     
     
         18 . An injection well for delivering an oxidant to a site including contaminated soil and groundwater comprising: 
 a sump partially embedded in bedrock;    a screened interval interconnected with the sump;    a well riser interconnected with the screened interval and extending from the screened interval to ground surface; and    a cover positionable over the well riser.    
     
     
         19 . The injection well of  claim 18  wherein the screened interval extends approximately five feet from the sump.  
     
     
         20 . The injection well of  claim 18  wherein the sump comprises a pipe with a bottom end cap.  
     
     
         21 . The injection well of  claim 18  further comprising means for pressurizing the well.  
     
     
         22 . The injection well of  claim 21  further comprising a pressure gauge for monitoring and maintaining pressure in the injection well.  
     
     
         23 . A method for treating a contaminated site comprising: 
 providing an injection well upstream of the contaminated site;    introducing a solid chemical oxidant into the injection well;    allowing groundwater to flow into the injection well;    dissolving the chemical oxidant into the groundwater;    allowing the groundwater with dissolved chemical oxidant to flow out of the injection well; and    allowing the dissolved chemical oxidant to treat the contaminated site.    
     
     
         24 . The method of  claim 23 , wherein the chemical oxidant is potassium permanganate.  
     
     
         25 . The method of  claim 24  wherein the chemical oxidant is in pellet form.  
     
     
         26 . The method of  claim 25  wherein the chemical oxidant is in powder form.  
     
     
         27 . The method of  claim 23 , further comprising: 
 sampling the groundwater downstream of the contaminated site; and    selectively increasing or decreasing the amount of chemical oxidant in the injection well based on the results of the sampling.    
     
     
         28 . The method of  claim 23  further comprising directing the groundwater to flow into the injection well by installing baffles upstream of the injection well.  
     
     
         29 . The method of  claim 28  further comprising dispersing the groundwater with dissolved chemical oxidant by installing a second baffle between the injection well and the contaminated site.