Evaluation of ISCO Field Applications and Performance

Krembs, Friedrich J.; Clayton, Wilson S.; Marley, Michael C.

doi:10.1007/978-1-4419-7826-4_8

Cited by 8 publications

(23 citation statements)

References 6 publications

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“…This was similar to previously reported NOD ranges (Mumford et al 2005 ;Huling and Pivetz 2006 ;Hønning et al 2007 ;Urynowicz 2008 ;Xu and Thomson 2009 ). The median value of MnO 4 − dosage reported by Krembs et al ( 2010Krembs et al ( , 2011 is low (0.4 g/kg; n = 24) ( Table 2 ) relative to long-term NOD values. Assuming that long-term persistence of MnO 4 − was needed to address contaminant mass transport and mass transfer limiting processes, this low MnO 4 − dosage applied suggests that the median range value used at many ISCO sites represents an under-design either in terms of oxidant volume or concentration.…”

Section: Natural Oxidant Demandsupporting

confidence: 90%

“…The median values reported for oxidant dosage (0.4 g/kg) and PV delivery (PV = 0.16) (Table ) (Krembs et al , ) suggests a less aggressive, low oxidant volume ISCO design which may be consistent with a mobile porosity ISCO design. This design appears likely to result in incomplete oxidant delivery, insufficient oxidant dosage within the ROI, and short duration oxidant persistence.…”

Section: Critical Analysis Of Permanganate Isco Design Parametersmentioning

confidence: 93%

“…Krembs et al (, ) compiled permanganate ISCO design parameters including the design and observed ROI (ft), oxidant dosage (g/kg), number of PVs delivered, number of delivery events, and duration of delivery events (days) (Table ). A critical analysis of these design parameters reported is preceded by the caveat that the number of case studies for the median value of each design parameter varied, and therefore only general observations are possible.…”

Section: Critical Analysis Of Permanganate Isco Design Parametersmentioning

confidence: 99%

“…Assuming the majority of the CVOCs mass in the ROI is immobilized either as residual NAPL or through adsorption onto aquifer solids, the displacement of the dissolved CVOC contaminant mass in the groundwater is projected to be limited relative to the total contaminant mass. Krembs et al ( 2010Krembs et al ( , 2011 compiled permanganate ISCO design parameters including the design and observed ROI (ft), oxidant dosage (g/kg), number of PVs delivered, number of delivery events, and duration of delivery events (days) ( Table 2 ). A critical analysis of these design parameters reported is preceded by the caveat that the number of case studies for the median value of each design parameter varied, and therefore only general observations are possible.…”

Section: Critical Analysis Of Mobile and Total Porosity Oxidant Injecmentioning

confidence: 99%

“…The vertical injection interval was not reported Krembs et al ( 2010Krembs et al ( , 2011 ). a 14-ft ROI (4.27 m), would involve injecting greater than three times more oxidant volume.…”

mentioning

confidence: 99%

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In Situ Chemical Oxidation: Permanganate Oxidant Volume Design Considerations

Huling¹,

Ross²,

Prestbo

2017

Groundwater Monitoring Rem

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Contaminant rebound and low contaminant removal are reported more frequently with in situ chemical oxidation than other in situ technologies. Although there are multiple causes for these results, a critical analysis indicates that low oxidant volume delivery is a key issue. The volume of oxidant injected is critical and porosity of the aquifer matrix can be used to estimate the pore volume. The total porosity (qT) is the volume of voids relative to the total volume of aquifer material. The mobile porosity (qM) is the fraction of voids that readily contributes to fluid displacement, and is less than qT leading to smaller estimates of oxidant volume. Injecting low‐oxidant volume may result in inadequate oxidant distribution and postinjection dispersal within the radius of influence, insufficient oxidant contact and oxidant loading, and incomplete treatment; whereas, greater oxidant volume achieves a greater oxidant footprint and may involve risk that the injected oxidant may migrate into nontarget areas and displacement of contaminated groundwater. Design guidelines and recommendations are provided that could help achieve more effective technology deployment, reduce the role of heterogeneities in the subsurface, and result in greater probability the oxidant is delivered to the targeted treatment zone.

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Section: Natural Oxidant Demandsupporting

confidence: 90%

Section: Critical Analysis Of Permanganate Isco Design Parametersmentioning

confidence: 93%

Section: Critical Analysis Of Permanganate Isco Design Parametersmentioning

confidence: 99%

Section: Critical Analysis Of Mobile and Total Porosity Oxidant Injecmentioning

confidence: 99%

“…The vertical injection interval was not reported Krembs et al ( 2010Krembs et al ( , 2011 ). a 14-ft ROI (4.27 m), would involve injecting greater than three times more oxidant volume.…”

mentioning

confidence: 99%

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In Situ Chemical Oxidation: Permanganate Oxidant Volume Design Considerations

Huling¹,

Ross²,

Prestbo

2017

Groundwater Monitoring Rem

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Developing slow-release persulfate candles to treat BTEX contaminated groundwater

Kambhu

Comfort²,

Chokejaroenrat

et al. 2012

Chemosphere

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The development of slow-release chemical oxidants for sub-surface remediation is a relatively new technology. Our objective was to develop slow-release persulfate-paraffin candles to treat BTEX-contaminated groundwater. Laboratory-scale candles were prepared by heating and mixing Na(2)S(2)O(8) with paraffin in a 2.25 to 1 ratio (w/w), and then pouring the heated mixture into circular molds that were 2.38 cm long and either 0.71 or 1.27 cm in diameter. Activator candles were prepared with FeSO(4) or zerovalent iron (ZVI) and wax. By treating benzoic acid and BTEX compounds with slow-release persulfate and ZVI candles, we observed rapid transformation of all contaminants. By using (14)C-labeled benzoic acid and benzene, we also confirmed mineralization (conversion to CO2) upon exposure to the candles. As the candles aged and were repeatedly exposed to fresh solutions, contaminant transformation rates slowed and removal rates became more linear (zero-order); this change in transformation kinetics mimicked the observed dissolution rates of the candles. By stacking persulfate and ZVI candles on top of each other in a saturated sand tank (14×14×2.5 cm) and spatially sampling around the candles with time, the dissolution patterns of the candles and zone of influence were determined. Results showed that as the candles dissolved and persulfate and iron diffused out into the sand matrix, benzoic acid or benzene concentrations (C(o)=1 mM) decreased by >90% within 7 d. These results support the use of slow-release persulfate and ZVI candles as a means of treating BTEX compounds in contaminated groundwater.

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