Physical Modeling of Air Flow During Air Sparging Remediation

Hu, Liming; Wu, Xiaofeng; Yan, Liu; Meegoda, Jay N.; Gao, Shengyan

doi:10.1021/es903853v

Cited by 70 publications

(27 citation statements)

References 14 publications

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“…It is well known that the remediation efficiency is primarily affected by the gas flow patterns, which are often categorized as channel flow, slug flow, or bubble flow [Brooks et al, 1999;Chen et al, 1996;Elder and Benson, 1999;Hu et al, 2010]. When gas is transported continuously, channel flow may occur.…”

Section: Air Spargingmentioning

confidence: 99%

Microbubble transport in water‐saturated porous media

Kong

Scheuermann

et al. 2015

Water Resources Research

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Laboratory experiments were conducted to investigate flow of discrete microbubbles through a water-saturated porous medium. During the experiments, bubbles, released from a diffuser, moved upward through a quasi-2-D flume filled with transparent water-based gelbeads and formed a distinct plume that could be well registered by a calibrated camera. Outflowing bubbles were collected on the top of the flume using volumetric burettes for flux measurements. We quantified the scaling behaviors between the gas (bubble) release rates and various characteristic parameters of the bubble plume, including plume tip velocity, plume width, and breakthrough time of the plume front. The experiments also revealed circulations of ambient pore water induced by the bubble flow. Based on a simple momentum exchange model, we showed that the relationship between the mean pore water velocity and gas release rate is consistent with the scaling solution for the bubble plume. These findings have important implications for studies of natural gas emission and air sparging, as well as fundamental research on bubble transport in porous media.

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Section: Air Spargingmentioning

confidence: 99%

Microbubble transport in water‐saturated porous media

Kong

Scheuermann

et al. 2015

Water Resources Research

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“…Based on the centrifuge tests employing glass beads as soil, Hu et al [40,41] simulated the air sparging under a wide range of sparging pressures and centrifuge g levels. Four samples with different particle size distribution were prepared and tested under different g -levels of 15, 30, 40 and 50.…”

Section: In-situ Remediation Of Gasolinementioning

confidence: 99%

A Review of Centrifugal Testing of Gasoline Contamination and Remediation

Meegoda

2011

IJERPH

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Leaking underground storage tanks (USTs) containing gasoline represent a significant public health hazard. Virtually undetectable to the UST owner, gasoline leaks can contaminate groundwater supplies. In order to develop remediation plans one must know the extent of gasoline contamination. Centrifugal simulations showed that in silty and sandy soils gasoline moved due to the physical process of advection and was retained as a pool of free products above the water table. However, in clayey soils there was a limited leak with lateral spreading and without pooling of free products above the water table. Amount leaked depends on both the type of soil underneath the USTs and the amount of corrosion. The soil vapor extraction (SVE) technology seems to be an effective method to remove contaminants from above the water table in contaminated sites. In-situ air sparging (IAS) is a groundwater remediation technology for contamination below the water table, which involves the injection of air under pressure into a well installed into the saturated zone. However, current state of the art is not adequate to develop a design guide for site implementation. New information is being currently generated by both centrifugal tests as well as theoretical models to develop a design guide for IAS. The petroleum contaminated soils excavated from leaking UST sites can be used for construction of highway pavements, specifically as sub-base material or blended and used as hot or cold mix asphalt concrete. Cost analysis shows that 5% petroleum contaminated soils is included in hot or cold mix asphalt concrete can save US$5.00 production cost per ton of asphalt produced.

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“…The available oxygen in the groundwater environment could be increased by introducing oxygen into the aquifer by sparging with air, pure oxygen or ozone and by the addition of H 2 O 2 or oxygen-releasing compounds. [10,11] Use of H 2 O 2 is a cost-effective approach that is attracting increased attention, because it is soluble in water and provides unlimited amounts of oxygen for biodegradation. Mukherjee et al have shown that the accretion of 0.01% (v/v) H 2 O 2 as an additional source of oxygen in the culture medium containing Bacillus subtilis DM-04 and Pseudomonas aeruginosa strains remarkably enhanced the biodegradation rate of benzene, toluene and three xylene isomers under oxygen-limited conditions.…”

Section: Introductionmentioning

confidence: 99%

Aerobic biodegradation of trichloroethylene and phenol co-contaminants in groundwater by a bacterial community using hydrogen peroxide as the sole oxygen source

Zhang

Wang

et al. 2014

Environmental Technology

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Trichloroethylene (TCE) and phenol were often found together as co-contaminants in the groundwater of industrial contaminated sites. An effective method to remove TCE was aerobic biodegradation by co-metabolism using phenol as growth substrates. However, the aerobic biodegradation process was easily limited by low concentration of dissolved oxygen (DO) in groundwater, and DO was improved by air blast technique with difficulty. This study enriched a bacterial community using hydrogen peroxide (H2O2) as the sole oxygen source to aerobically degrade TCE by co-metabolism with phenol in groundwater. The enriched cultures were acclimatized to 2-8 mM H2O2 which induced catalase, superoxide dismutase and peroxidase to decompose H2O2 to release O2 and reduce the toxicity. The bacterial community could degrade 120 mg/L TCE within 12 days by using 8 mM H2O2 as the optimum concentration, and the TCE degradation efficiency reached up to 80.6%. 16S rRNA gene cloning and sequencing showed that Bordetella, Stenotrophomonas sp., Sinorhizobium sp., Variovorax sp. and Sphingobium sp. were the dominant species in the enrichments, which were clustered in three phyla: Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria. Polymerase chain reaction detection proved that phenol hydroxylase (Lph) gene was involved in the co-metabolic degradation of phenol and TCE, which indicated that hydroxylase might catalyse the epoxidation of TCE to form the unstable molecule TCE-epoxide. The findings are significant for understanding the mechanism of biodegradation of TCE and phenol co-contamination and helpful for the potential applications of an aerobic bioremediation in situ the contaminated sites.

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Physical Modeling of Air Flow During Air Sparging Remediation

Cited by 70 publications

References 14 publications

Microbubble transport in water‐saturated porous media

Microbubble transport in water‐saturated porous media

A Review of Centrifugal Testing of Gasoline Contamination and Remediation

Aerobic biodegradation of trichloroethylene and phenol co-contaminants in groundwater by a bacterial community using hydrogen peroxide as the sole oxygen source

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