Field‐scale evaluation of in situ cosolvent flushing for enhanced aquifer remediation

Rao, P. Suresh C.; Annable, Michael D.; Sillan, Randall K.; Dai, David Yun; Hatfield, Kirk; Graham, Wendy D.; Wood, A. Lynn; Enfield, Carl G.

doi:10.1029/97wr02145

Cited by 160 publications

(97 citation statements)

References 20 publications

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“…The following trend in the NAPL distribution based on soil core analysis prior to cosolvent flushing was reported by Rao et al [1997]: (1) the NAPL was located in a 1.5-m smear zone immediately above the clay confining unit and (2) the zone of highest NAPL contamination was located --•0.3 m above the clay unit. The IWPT test conducted prior to cosolvent flushing indicated an average NAPL saturation (SN) of ---5% [Annable et al, 1998].…”

Section: Site Descriptionmentioning

confidence: 99%

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Evaluation of in situ cosolvent flushing dynamics using a network of spatially distributed multilevel samplers

Sillan¹,

Annable²,

Rao³

et al. 1998

Water Resources Research

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Section: Site Descriptionmentioning

confidence: 99%

“…NAPL removal effectiveness was also calculated using preflushing and postflushing soil cores [Rao et al, 1997]. These values are presented along with those calculated using the IWPT tests (Table 3) …”

Section: Site Descriptionmentioning

confidence: 99%

Evaluation of in situ cosolvent flushing dynamics using a network of spatially distributed multilevel samplers

Sillan¹,

Annable²,

Rao³

et al. 1998

Water Resources Research

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“…The periodic burning of the wastes has probably altered the composition of the NAPL, and many of the chemical components have not been identified. Additional details of the site contamination are given by Montgomery Watson [1995], Rao et al [1997], and McCray and Brusseau [1998].…”

Section: Field Sitementioning

confidence: 99%

Field test of high molecular weight alcohol flushing for subsurface nonaqueous phase liquid remediation

Falta¹,

Lee²,

Brame³

et al. 1999

Water Resources Research

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Abstract. A pilot scale field test of non-aqueous phase liquid (NAPL) removal using high molecular weight alcohols was conducted at Operable Unit 1, Hill Air Force Base, Utah. Petroleum hydrocarbons and spent solvents were disposed of in chemical disposal pits at this site, and these materials are now present in the subsurface in the form of a light nonaqueous phase liquid (LNAPL). This LNAPL is a complex mixture of aromatic and aliphatic hydrocarbons, chlorinated solvents, and other compounds. The field experiment was performed in a 5 rn by 3 rn confined test cell, formed by driving interlocking sheet pile walls through the contaminated zone into an underlying clay. The test involved the injection and extraction of about four pore volumes (1 pore volume = 7000 L) of a mixture of 80% tert-butanol and 15% n-hexanol. The contaminants were removed by a combination of NAPL mobilization and enhanced dissolution, and the results of postflood soil coring indicate better than 90% removal of the more soluble contaminants (trichloroethane, toluene, ethylbenzene, xylenes, trimethylbenzene, naphthalene) and 70-80% removal of less soluble compounds (decane and undecane). The results of preflood and postflood NAPL partitioning tracer tests show nearly 80% removal of the total NAPL content from the test cell. The field data suggest that a somewhat higher level of removal could be achieved with a longer alcohol injection. IntroductionIt is now known that relatively small nonaqueous phase liquid (NAPL) source zones are capable of producing large contaminated groundwater plumes. While methods such as pumping and treating the contaminated water or funneling the water through reactive walls have been effective for plume control, they do not effectively address the source of the plume. Given that these source zones may continue to release contaminants for many decades or centuries, a large effort is now focused on the development of source zone removal methods. Often these techniques must be applied in situ, owing to the depth of contamination or to the presence of buildings and utilities which prevent excavation. The Rao et al. [1997] field test was performed in an isolated test cell, and it consisted of injecting about nine pore volumes of a 70% ethanol, 12% n-pentanol solution. They reported a bulk NAPL removal of -81%, with a higher removal efficiency for several individual compounds.

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“…Two cosolvent flushing demonstrations were conducted at Hill Air Force Base (AFB), Utah in isolated test cells installed in a sand and gravel aquifer contaminated with a multi-component NAPL Sillan et al, 1998a;Falta et al, 1999). Rao et al (1997) demonstrated NAPL remediation by enhanced dissolution. The test cell was approximately 4.3 m long by 3.6 m wide, and the clay confining unit was 6 m below grade.…”

Section: Technology Status: Cosolvent Flushingmentioning

confidence: 99%

“…Enhanced source-zone remediation can expedite the removal of contaminants. One enhanced source zone remediation technique is in situ cosolvent flushing, which involves the addition of miscible organic solvents to water to increase the solubility or mobility of the NAPL (Imhoff et al, 1995;Falta et al, 1997;Lunn and Kueper, 1997;Rao et al, 1997;Augustijn et al, 1997;Lowe et al, 1999). In the case of DNAPLs, increased mobility can result in greater contaminant risk due to the potential for downward migration, and density modification of the NAPL has been proposed to prevent this risk (Roeder et al, 1996;Lunn and Kueper, 1997;Lunn and Kueper, 1999).…”

Section: In-situ Flushing Technologymentioning

confidence: 99%

Federal Integrated Biotreatment Research Consortium (FIBRC): Flask to Field Initiative

Bajpai¹,

Felt²,

Nestler³

et al. 2002

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Field‐scale evaluation of in situ cosolvent flushing for enhanced aquifer remediation

Cited by 160 publications

References 20 publications

Evaluation of in situ cosolvent flushing dynamics using a network of spatially distributed multilevel samplers

Evaluation of in situ cosolvent flushing dynamics using a network of spatially distributed multilevel samplers

Field test of high molecular weight alcohol flushing for subsurface nonaqueous phase liquid remediation

Federal Integrated Biotreatment Research Consortium (FIBRC): Flask to Field Initiative

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