Redox chemistry of iron and manganese minerals in river-recharged aquifers: A model interpretation of a column experiment

Matsunaga, Takeshi; Karametaxas, G.; Gunten, H. R. von; Lichtner, Peter C.

doi:10.1016/0016-7037(93)90107-8

Cited by 75 publications

(36 citation statements)

References 30 publications

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“…Hydrogen sulfide is highly reactive, causing the reductive dissolution of some amorphous and poorly crystalline Fe(III) oxides (e.g., ferrihydrite) and the subsequent precipitation of the Fe(II) as amorphous FeS (Matsunaga et al 1993). The reduction of structural Fe(III) in layer silicates without dissolution may also occur (Gan et al 1992).…”

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

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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)...

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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

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“…The rates of O 2 and NO 3 À consumption were lower and the rates of SO 4 2À consumption and Fe(II) production higher on September 12, 1994 than on August 24, 1993. The Fe(II) production may even have been higher than calculated since precipitation of Fe(II) as FeS or FeCO 3 (Matsunaga et al, 1993;Von Gunten and Zobrist, 1993) was not included. On October 18, 1995, October 29, 1996 and November 3, 1997, the consumption of NO 3 À , SO 4 2À and the production of Fe(II) and Mn(II) was again lower than on September 12, Hunkeler et al (1999).…”

Section: Total Rates Of Consumption and Production Of Selected Speciesmentioning

confidence: 99%

Engineered and subsequent intrinsic in situ bioremediation of a diesel fuel contaminated aquifer

Hunkeler

Höhener

Zeyer

2002

Journal of Contaminant Hydrology

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A diesel fuel contaminated aquifer in Menziken, Switzerland was treated for 4.5 years by injecting aerated groundwater, supplemented with KNO 3 and NH 4 H 2 PO 4 to stimulate indigenous populations of petroleum hydrocarbon (PHC) degrading microorganisms. After dissolved PHC concentrations had stabilized at a low level, engineered in situ bioremediation was terminated. The main objective of this study was to evaluate the efficacy of intrinsic in situ bioremediation as a follow-up measure to remove PHC remaining in the aquifer after terminating engineered in situ bioremediation. In the first 7 months of intrinsic in situ bioremediation, redox conditions in the source area became more reducing as indicated by lower concentrations of SO 4 2À and higher concentrations of Fe(II) and CH 4 . In the core of the source area, strongly reducing conditions prevailed during the remaining study period (3 years) and dissolved PHC concentrations were higher than during engineered in situ bioremediation. This suggests that biodegradation in the core zone was limited by the availability of oxidants. In lateral zones of the source area, however, gradually more oxidized conditions were reestablished again, suggesting that PHC availability increasingly limited biodegradation. The total DIC production rate in the aquifer decreased within 2 years to about 25% of that during engineered in situ bioremediation and remained at that level. Stable carbon isotope analysis confirmed that the produced DIC mainly originated from PHC mineralization. The total rate of DIC and CH 4 production in the source area was more than 300 times larger than the rate of PHC elution. This indicates that biodegradation coupled to consumption of naturally occurring oxidants was an important process for removal of PHC which remained in the aquifer after terminating engineered measures. D

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“…The Riverbank filtration represents a natural process to use in first stage in the water treatment. This process is always in direct contact by the contamination of the organic, inorganic substances, viruses polluting and bacteria which can modify the quality of drinking water (Sontheimer, 1980;Jacobs et al, 1988;Magee et al, 1991;Matsunga et al, 1993). Contaminant transport in Riverbank filtration has been investigated by several researchers using different model.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Contaminants Transport in Confined Medium

Charfi¹,

Safi²

2010

Numerical Simulations - Examples and Applications in Computational Fluid Dynamics

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Redox chemistry of iron and manganese minerals in river-recharged aquifers: A model interpretation of a column experiment

Cited by 75 publications

References 30 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

Engineered and subsequent intrinsic in situ bioremediation of a diesel fuel contaminated aquifer

Numerical Simulation of Contaminants Transport in Confined Medium

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