Abiotic reduction of aquifer materials by dithionite: A promising in-situ remediation technology

Amonette, James E.; Szecsody, James E.; Schaef, Herbert T.; Gorby, Yuri A.; Fruchter, Jonathan S.; Templeton, J. Charles

doi:10.2172/43791

Cited by 56 publications

(66 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reduction of structural Fe(III) in layer silicates without dissolution may also occur (Gan et al 1992). These reduced phases store reductive capacity in sediments and subsequently can reduce soluble contaminants such as Cr(VI) to form insoluble precipitates (Amonette et al 1994;Fredrickson and Gorby 1996;Deng and Stone 1996). Additionally, H 2 S may directly reduce metallic contaminants such as Cr(VI) (Kim et al 2001;Bidoglio et al 1993).…”

Section: Sulfate Reduction Processmentioning

confidence: 99%

Treatability Study of In Situ Technologies for Remediation of Hexavalent Chromium in Groundwater at the Puchack Well Field Superfund Site, New Jersey

Vermeul¹,

Szecsody²,

Truex³

et al. 2006

View full text Add to dashboard Cite

SummaryThis treatability study was conducted by Pacific Northwest National Laboratory (PNNL), at the request of the U. S. Environmental Protection Agency (EPA) Region 2, to evaluate the feasibility of using in situ treatment technologies for chromate reduction and immobilization at the Puchack Well Field Superfund site in Pennsauken Township, New Jersey. In addition to in situ reductive treatments, which included the evaluation of both abiotic and biotic reduction of Puchack aquifer sediments, natural attenuation mechanisms were evaluated (i.e., chromate adsorption and reduction). Chromate exhibited typical anionic adsorption behavior, with greater adsorption at lower pH, at lower chromate concentration, and at lower concentrations of other competing anions. Competitive anions, sulfate in particular (at 50 mg/L), suppressed chromate adsorption by up to 50%. Chromate adsorption was not influenced by inorganic colloids.Results from long-term experiments indicate that natural chromate reduction occurs in Puchack sediments. Sediment composites of seven different Puchack aquifer units showed either no reduction or very slow chromate reduction (0.3 to 3.1 year half-life). However, three selected sediments showed much more rapid reduction (half lives: 49 h to ~3000 h). Although the spatial variability in natural reductive capacity appears to be relatively large, experimental results indicate that chromate reduction can remain viable even in the presence of dissolved oxygen. Most sediments that showed some natural reduction of chromate had very small reductive capacities (average 2.76 ± 1.02 µmol/g), but one sediment had a large reductive capacity (636 µmol/g) with considerable amorphous ferrous iron and 2.25% organic carbon (i.e., contained clays, iron oxides, and possibly lignite). There was wide variability in the iron oxide content of Puchack sediments.Results from chemical reduction experiments on Puchack sediments showed a considerable increase in the reductive capacity (average 60.2 ± 25.6 µmol/g, maximum of 390 µmol/g), indicating that reductive treatment may be an effective approach when deployed at the field scale. The average measured reductive capacity, assuming typical site groundwater chemistry conditions, would result in a treatment zone longevity of 360 pore volumes or 39 years of treatment for a uniform treatment zone 40 ft wide and an average groundwater velocity of 1 ft/d. It was also shown that reductive capacity is a function of pH. The capacity of the sediment column to consume 2.0 mg/L chromate and 8.4 mg/L dissolved oxygen (saturated conditions) was estimated to be 310 pore volumes at pH 4.5 and 480 pore volumes at pH 7.0. Chromate reduction/immobilization was shown to be effective in four long-term column studies at pH 4.5 to 7.0. Chromate was removed in all columns initially, then partial chromate breakthrough occurred by 170 pore volumes for pH values of 4.5 and 5.3, 280 pore volumes at pH 6.2, and 340 pore volumes at pH 7.0. There was no evidence of mobile Cr(III) species at any pH. Iron (II)...

show abstract

Section: Sulfate Reduction Processmentioning

confidence: 99%

Treatability Study of In Situ Technologies for Remediation of Hexavalent Chromium in Groundwater at the Puchack Well Field Superfund Site, New Jersey

Vermeul¹,

Szecsody²,

Truex³

et al. 2006

View full text Add to dashboard Cite

show abstract

“…Chemical reduction by aqueous solutions of sodium dithionite has been studied extensively at the Hanford site (e.g. Amonette et al, 1994;Williams et al, 2000). Other aqueous solutions such as those containing Fe(II), Cu(I), or Sn(II) may also reduce technetium, though Cui and Eriksen (1996) found that reduction by Fe(II) was quite slow.…”

Section: Technical Basismentioning

confidence: 99%

Potential In Situ Remediation of 129-I and 99-Tc in Groundwater Associated with the F-Area Seepage Basins

Denham¹

2003

View full text Add to dashboard Cite

“…Reactive zones as such have been produced by the addition of sodium dithionite, a strong inorganic reductant, in buffered aqueous solution to a chromium-contaminated aquifer at the Hanford site in Richland, Washington. Considerable laboratory work has also focused on reduction of chlorinated solvents by dithionite-reduced clays and sediments (Amonette et al, 1994, Amonette et al, 1995.…”

Section: Screening Study: Mined Minerals As the Source Of Iron Materialsmentioning

confidence: 99%

Development of an integrated in-situ remediation technology. Topical report for Task {number_sign}3.2 entitled, ``Modeling and iron dechlorination studies`` (September 26, 1994--August 31, 1997)

Shapiro¹,

Sivavec²,

Principe

1997

View full text Add to dashboard Cite

Abiotic reduction of aquifer materials by dithionite: A promising in-situ remediation technology

Cited by 56 publications

References 2 publications

Treatability Study of In Situ Technologies for Remediation of Hexavalent Chromium in Groundwater at the Puchack Well Field Superfund Site, New Jersey

Treatability Study of In Situ Technologies for Remediation of Hexavalent Chromium in Groundwater at the Puchack Well Field Superfund Site, New Jersey

Potential In Situ Remediation of 129-I and 99-Tc in Groundwater Associated with the F-Area Seepage Basins

Development of an integrated in-situ remediation technology. Topical report for Task {number_sign}3.2 entitled, ``Modeling and iron dechlorination studies`` (September 26, 1994--August 31, 1997)

Contact Info

Product

Resources

About