Method of using pulsed ozone to treat soils containing organic contaminants

Abstract

A method of treating a solid matrix containing organic contaminants is provided. The method comprises the steps of a) injecting ozone into the solid matrix for a period of time known as the pulse duration; b) interrupting the injection of ozone into the solid matrix for a period of time known as the gap duration; and c) repeating step a) at least one additional time. Gap durations of from about 2 hours to about 48 hours are disclosed. Pulse durations of from about 0.25 hours to about 8 hours are also disclosed. Recalcitrant organic contaminants are treated.

We claim:  
     
         1 . A method of treating a solid matrix containing organic contaminants comprising the steps of 
 a) injecting ozone into the solid matrix for a period of time known as the pulse duration;    b) interrupting the injection of the ozone into the solid matrix for a period of time known as the gap duration; and    repeating step a) at least one additional time.    
     
     
         2 . The method of  claim 1  wherein the gap duration is from about 2 hours to about 48 hours.  
     
     
         3 . The method of  claim 1  wherein the gap duration is from about 24 hours to about 36 hours.  
     
     
         4 . The method of  claim 1  wherein the organic contaminant is recalcitrant and the gap duration is from about 36 hours to about 48 hours.  
     
     
         5 . The method of  claim 1  wherein the pulse duration is from about 0.25 hours to about 8 hours.  
     
     
         6 . The method of  claim 1  wherein the pulse duration is about 0.25 hours.  
     
     
         7 . The method of  claim 1  wherein the pulse duration is from about 2 hours to about 3 hours.  
     
     
         8 . The method of  claim 1  wherein the gap duration is from about 24 hours to about 36 hours and the pulse duration is about 0.25 hours.  
     
     
         9 . The method of  claim 1  wherein the gap duration is from about 24 hours to about 36 hours and the pulse duration is from about 2 hours to about 3 hours.  
     
     
         10 . The method of  claim 1  wherein the gap duration is from about 36 hours to about 72 hors and the pulse duration is less than about 1 hour.  
     
     
         11 . The method of  claim 10  wherein oxygen or air is injected into the solid matrix during the gap duration step b).  
     
     
         12 . The method of  claim 1  wherein the organic contaminants are PAHs, chlorophenols, substituted aromatics, greater than C-8 hydrocarbons, pesticides, phthlates, explosives, surfactants or wood related wastes.  
     
     
         13 . The method of  claim 1  wherein steps a) and b) are sequentially repeated multiple times until a substantial amount of the organic contaminants has been destroyed.  
     
     
         14 . The method of  claim 1  wherein the solid matrix is an unsaturated soil.  
     
     
         15 . The method of  claim 1  wherein the solid matrix is saturated with water.  
     
     
         16 . The method of  claim 1  wherein the solid matrix is a sludge.  
     
     
         17 . The method of  claim 14  wherein the solid matrix is treated in situ.  
     
     
         18 . The method of  claim 15  wherein the solid matrix is treated in situ.  
     
     
         19 . The method of  claim 1  wherein the organic contaminants are PAHs.  
     
     
         20 . The method of  claim 1  wherein the organic contaminants are coal tars.  
     
     
         21 . The method of  claim 1  wherein the organic contaminants are creosote.  
     
     
         22 . An in situ method of treating soil containing recalcitrant organic contaminants comprising the steps of 
 a) injecting ozone into the soil, in situ, for a period of time known as the pulse duration;    b) interrupting the injection of the ozone into the soil for a period of time known as the gap duration; and    sequentially repeating steps a) and b) until a substantial amount of the organic contaminants has been destroyed.    
     
     
         23 . The method of  claim 22  wherein the gap duration is from about 24 hours to about 36 hours and the pulse duration is about 0.25 hours.  
     
     
         24 . The method of  claim 23  wherein the pulse duration is from about 2 hours to about 3 hours.  
     
     
         25 . The method of  claim 22  wherein the organic contaminants are PAHs, chlorophenols, substituted aromatics, greater than C-8 hydrocarbons, pesticides, phthlates, explosives, surfactants or wood related wastes.  
     
     
         26 . A method of treating a solid matrix containing organic contaminants and bacteria capable of biodegrading the organic contaminant, comprising the steps of 
 a) injecting ozone into the solid matrix for a period of time known as the pulse duration, the amount of ozone injected being insufficient to completely destroy the bacteria,    b) interrupting the injection of ozone into the solid matrix for a period of time known as the gap duration, the gap duration being sufficiently long so as to allow the regeneration of the bacteria and the biodegradation of the organic contaminants;    c) injecting air or oxygen into the solid matrix during the gap duration; and    d) repeating steps a), b) and c) multiple times.    
     
     
         27 . The method of  claim 26  wherein the gap duration is from about 36 hours to about 72 hours and the pulse duration is less than about 1 hour.  
     
     
         28 . The method of  claim 27  wherein the pulse duration is about 0.25 hours.  
     
     
         29 . The method of  claim 26  wherein additional bacteria capable of biodegrading the organic contaminant is added to the solid matrix during the gap duration.