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US 6,783,678 B2Granted
Halogenated solvent remediation
AssigneeBechtel BWXT Idaho, LLC
InventorKent S. Sorenson
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AssigneeBechtel BWXT Idaho, LLC
InventorKent S. Sorenson
Estimating the term…
Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. A preferred method includes adding a composition to the ground water wherein the composition is an electron donor for microbe-mediated reductive dehalogenation of the halogenated solvents and enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative compositions effective in these methods include surfactants such as C2-C4 carboxylic acids and hydroxy acids, salts thereof, esters of C2-C4 carboxylic acids and hydroxy acids, and mixtures thereof. Especially preferred compositions for use in these methods include lactic acid, salts of lactic acid, such as sodium lactate, lactate esters, and mixtures thereof. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the composition.
A method for enhancing in situ bioremediation of a nonaqueous halogenated solvent in ground water comprising adding to the ground water an amount of an electron donor sufficient for a halo-respiring microbe in the ground water to use the nonaqueous halogenated solvent as an electron acceptor, thereby reductively dehalogenating the nonaqueous halogenated solvent into innocuous compounds, wherein said electron donor comprises a mixture of (a) a member selected from the group consisting of C2-C4 carboxylic acids and salts thereof, C2-C4 hydroxy acids and salts thereof, and mixtures thereof, and (b) a member selected from the group consisting of esters of C2-C4 carboxylic acids, esters of C2-C4 hydroxy acids, and mixtures thereof.
A method for enhancing bioremediation of a nonaqucous chlorinated solvent in ground water comprising adding to the ground water an amount of an electron donor sufficient for a chloro-respiring microbe to use the nonaqueous chlorinated solvent as an electron acceptor, thus reductively dechlorinating the nonaqueous chlorinated solvent into innocuous compounds, wherein said electron donor comprises 3% to 60% by weight of a member selected from the group consisting of C2-C4 carboxylic acid and salts thereof, C2-C4 hydroxy acids and salts thereof, and mixtures thereof.
A method for enhancing mass transfer of a nonaqueous halogenated solvent present in a nonaqueous residual source of contamination in ground water, said ground water comprising an aqueous phase, into said aqueous phase comprising adding to said ground water an effective amount of a composition that donates electrons for microbe-mediated reductive dehalogenation of said nonaqueous halogenated solvent into innocuous compounds and functions as a surfactant or co-solvent for solubilizing said nonaqueous halogenated solvent, wherein said composition comprises a mixture of (a) a member selected from the group consisting of C2-C4 carboxylic acid and salts thereof, C2-C4 hydroxy acids and salts thereof, and mixtures thereof and (b) a member selected from the group consisting of esters of C2-C4 carboxylic acids, esters of C2-C4 hydroxy acids, and mixtures thereof.
A method for enhancing mass transfer of a nonaqueous halogenated solvent present in a nonaqueous residual source of contamination in ground water, said ground water comprising an aqueous phase, into said aqueous phase comprising adding to said ground water an effective amount of a composition that donates electrons for microbe-mediated reductive dehalogenation of said nonaqueous halogenated solvent into innocuous compounds and functions as a surfactant or co-solvent for solubilizing said nonaqueous halogenated solvent, wherein said composition comprises 3% to 60% by weight of a member selected from the group consisting of C2-C4 carboxylic acid and salts thereof, C2-C4 hydroxy acids and salts thereof, and mixtures thereof.
Dependencies are inferred from the claim text.