US 6,884,352 B1 · Treating toxic solvents and heavy metal contaminants in groundwater and soil using iron sulfides microbial geochemical treatment zone

Abstract

A method a process involving the application of a labile organic substrate, with supplied sulfate as needed, to a soil and ground water supply for the express purpose of stimulating sulfate reduction to facilitate the formation of mineral iron sulfides or other reduced reactive minerals, abiotically treats soil contaminants, including chlorinated solvents, and hexavalent chromium, with an iron monosulfide microbial geochemical treatment zone. Other iron sulfide compounds, or generally FexSy, may also comprise the treatment zone in addition to iron monosulfide. The process also includes, in some cases, the supplementation of sulfate to ground water where insufficient natural supply exists, wherein a solution of organic and dissolved reactive sulfate introduced to the soil and ground water, the introduction of sulfate tailored to the individual site conditions to meet contaminant mass constraints.

Claims10

Dependent claims

A process for the creation of an iron sulfide microbial geochemical treatment zone to treat toxic and harmful contaminants in ground water and in the soil, the process comprising the steps of:

(A) locating a contamination zone in soil and ground water containing a target contaminant;
(B) introducing a quantity of labile organic compound to the contamination zone;
(C) adding a sulfate reducing heterotrophic soil bacteria to the contamination zone, oxidizing the organic while reducing a naturally occurring sulfate present within the soil and ground water;
(D) adding additional sulfate to the contamination zone to complete the redox reactions where the naturally occurring sulfate is insufficient, producing a quantity of HS within the contamination zone, which in turn reacts with a naturally occurring iron (III) present within the contamination zone;
(E) forming a deposit of an iron sulfide (FexSy) within the contamination zone;
(F) oxidizing the target contaminant;
and
(G) contemporaneously creating an iron sulfide microbial geochemical treatment zone further oxidizing any target remaining contaminant which may pass through or present itself within the iron sulfide microbial geochemical treatment zone swept into such treatment zone via ground water advection, dispersion, or molecular diffusion.

5 more elements

A process for the creation of an iron monosulfide microbial geochemical treatment zone to treat toxic and harmful contaminants in ground water and in the soil, the process comprising the steps of:

(A) locating a contamination zone in soil and ground water containing a target contaminant;
(B) introducing a quantity of labile organic compound to the contamination zone;
(C) adding a sulfate reducing heterotrophic soil bacteria to the contamination zone, oxidizing the organic while reducing a naturally occurring sulfate present within the soil and ground water;
(D) adding additional sulfate to the contamination zone to complete the redox reactions where the naturally occurring sulfate is insufficient, producing a quantity of HS within the contamination zone, which in turn reacts with a naturally occurring iron (III) present within the contamination zone;
(E) forming a deposit of an iron monosulfide (FeS) within the contamination zone;
(F) oxidizing the target contaminant;
and
(G) contemporaneously creating an iron monosulfide microbial geochemical treatment zone further oxidizing any target remaining contaminant which may pass through or present itself within the iron monosulfide microbial geochemical treatment zone swept into such treatment zone via ground water advection, dispersion, or molecular diffusion.

5 more elements

Dependencies are inferred from the claim text.

Treating toxic solvents and heavy metal contaminants in groundwater and soil using iron sulfides microbial geochemical treatment zone

Life of this patent

Treating toxic solvents and heavy metal contaminants in groundwater and soil using iron sulfides microbial geochemical treatment zone

Life of this patent

Abstract

Claims10