Soil and water remediation method and apparatus for treatment of recalcitrant halogenated substances

Abstract

Disclosed are methods, apparatuses and systems for the remediation of contaminated soils, groundwater, water, and/or waste using a combination of reagents. The disclosed methods may be used to treat various recalcitrant halogenated substances, such as perfluoroalkyls and polyfluoroalkyls. Particular combinations of reagents that may be used in the disclosed methods include but are not limited to: (1) persulfate, oxygen and ozone; (2) persulfate, salt, oxygen and ozone; (3) persulfate, phosphate, and/or oxygen; (4) persulfate, phosphate, oxygen and ozone; (5) persulfate, phosphate, salt and oxygen (6) persulfate, phosphate, salt, oxygen and ozone; (7) oxygen and salt; and (8) air and salt. The disclosed methods may include the transfer of contaminants from an aqueous phase to a foam prior to the destruction of the contaminants.

What is claimed is: 
     
         1 . A contaminant remediation system, comprising:
 a treatment zone comprising a contaminant;   at least one well extending below a groundwater surface in the treatment zone; and   a headspace positioned above the groundwater surface in at least one of the at least one well and the treatment zone   wherein the at least one well is configured to transfer at least some of the contaminant to a foam to form a foam comprising transferred contaminant,   wherein the at least one well is in fluid communication with a vacuum source for controlling at least one of a rate of foam formation and contaminant removal.   
     
     
         2 . The apparatus of  claim 1 , further comprising a trap in fluid communication with the headspace for collecting at least a portion of the foam comprising transferred contaminant. 
     
     
         3 . The apparatus of  claim 1 , wherein the trap includes at least one of a water trap, a solid phase extraction, granular activated carbon, or filtration. 
     
     
         4 . The apparatus of  claim 1 , wherein the at least one well comprises at least one conduit. 
     
     
         5 . The apparatus of  claim 4 , wherein the at least one conduit is configured for adding gas bubbles to the at least one well. 
     
     
         6 . The apparatus of  claim 5 , wherein the gas bubbles are microbubbles and/or nanobubbles. 
     
     
         7 . The apparatus of  claim 5 , wherein the gas bubbles urge the contaminant from the liquid phase into a foam. 
     
     
         8 . The apparatus of  claim 4 , wherein the at least one conduit is configured for transporting one or more reagents selected from a list comprising air, nitrogen, oxygen, nitrous oxide, cyclodextrin, hydrogen peroxide, persulfate, a buffer, an activator, a catalyst, a complexing agent, a surfactant, and a co-solvent. 
     
     
         9 . The apparatus of  claim 1 , wherein the treatment zone is a trench. 
     
     
         10 . The apparatus of  claim 9 , wherein the trench is extends below the groundwater surface. 
     
     
         11 . The apparatus of  claim 10 , further comprising a sparger positioned in at least one of the trench and the at least one well. 
     
     
         12 . The apparatus of  claim 1 , wherein the at least one well is positioned vertically. 
     
     
         13 . The apparatus of  claim 1 , wherein the contaminant comprises poly- and perfluoroalkyl substances (PFAS). 
     
     
         14 . The apparatus of  claim 1 , wherein the contaminant remediation system is configured to reduce a concentration of PFAS by at least 50%. 
     
     
         15 . The apparatus of  claim 1 , wherein the contaminant is destroyed by one of at least one of oxidation, reduction, sonication, ozonation, and defluorination. 
     
     
         16 . A method of removing poly- and/or perfluoroalkyl substances (PFAS) from water, the method comprising:
 forming a foam by passing gas bubbles through an aqueous phase contaminated with a contaminant comprising poly- and/or perfluoroalkyl substances (PFAS);   transferring at least some of the contaminant to the foam to form a foam comprising transferred contaminant; and   destroying at least a portion of the transferred contaminant.   
     
     
         17 . The method of  claim 16 , further comprising reducing a concentration of PFAS by at least 50%. 
     
     
         18 . The method of  claim 16 , further comprising removing the contaminant by at least one of oxidation, reduction, sonication, ozonation, and defluorination. 
     
     
         19 . The method of  claim 16 , further comprising adding at least one of persulfate, ozone, hydrogen peroxide, oxygen, air, nitrogen, cyclodextrin, a buffer, and a salt to the aqueous phase. 
     
     
         20 . The method of  claim 16 , further comprising controlling a rate of foam formation by controlling at least one of the gas phase pressure or vacuum, gas flow rate, gas bubble size and bubble density per volume.