In-situ subsurface extraction and decontamination

摘要

A method of decontaminating ground media. The method includes drilling an injection hole into ground media to a depth at or below where contaminants are also present, drilling one or more extraction holes into the ground media in close proximity to the injection hole, injecting a reagent into the injection hole, treating the ground media for a time sufficient to have a chelating agent chelate a metal present in the ground media, reacting the chelated metal with a peroxide to produce hydroxide ions, contacting the reagent with the ground media to decrease its permeability, contacting contaminants in the ground media with the hydroxide ions to convert the contaminants to environmentally safe compounds, increasing the pressure of the reagent into the ground media, further reducing the permeability of the ground media to release trapped contaminants, and transferring contaminants from the ground media to above a surface of the ground media.

主权项

1. A method of decontaminating ground media comprising clayey materials, halogenated organic contaminants and a metal compound, the method comprising:
drilling an injection hole into the ground media comprising the metal compound, to a depth at or below where contaminants are also present; drilling one or more extraction holes into the ground media in close proximity to the injection hole; injecting a reagent into the injection hole at a flow rate and an initial pressure, the reagent comprising an alkaline aqueous solution having a pH of at least 7, the alkaline aqueous solution comprising a cation, a peroxide, and a chelating agent; treating the ground media for a time sufficient to have the chelating agent chelate the metal of the metal compound present in the ground media; reacting the chelated metal with the peroxide to catalytically convert the peroxide to oxidizing agents and hydroxide ions; contacting the reagent with the ground media in an amount sufficient to decrease its permeability; contacting the contaminants in the ground media with the hydroxide ions to convert the contaminants through nucleophilic substitution to environmentally safe, non-toxic compounds, comprising a gas; increasing the pressure of the reagent into the ground media, to diffuse the reagent further into the ground media, and to generate additional reaction; further reducing the permeability of the ground media, to release contaminants trapped therein; and transferring contaminants from the ground media to above a surface of the ground media through pressure transfer.