A Simplified Image Analysis Method to Study LNAPL Migration in Porous Media

Flores, Giancarlo; Tanaka, Katsumi; Inui, Tomoyuki; Kamon, Masashi

doi:10.3208/sandf.51.835

Cited by 35 publications

(12 citation statements)

References 14 publications

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“…Hence, this method allows for the measurement of the degree of saturation of two fluids in a three-phase system (Flores et al, 2011;Kechavarzi et al, 2005;Kechavarzi et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Image analysis method for the measurement of water saturation in a two-dimensional experimental flow tank

Belfort

Weill

Lehmann

2017

Journal of Hydrology

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A novel, non-invasive imaging technique is proposed that determines 2D maps of water content in unsaturated porous media. This method directly relates digitally measured intensities to the water content of the porous medium. This method requires the classical image analysis steps, i.e., normalization, filtering, background subtraction, scaling and calibration. The main advantages of this approach are that no calibration experiment is needed, because calibration curve relating water content and reflected light intensities is established during the main monitoring phase of each experiment and that no tracer or dye is injected into the flow tank. The procedure enables effective processing of a large number of photographs and thus produces 2D water content maps at high temporal resolution. A drainage / imbibition experiment in a 2D flow tank with inner dimensions of 40 cm x 14 cm x 6 cm (L x W x D) is carried out to validate the methodology. The accuracy of the proposed approach is assessed using a statistical framework to perform an error analysis and numerical simulations with a state-of-the-art computational code that solves the Richards' equation. Comparison of the cumulative mass leaving and entering the flow tank and water content maps produced by the photographic measurement technique and the numerical simulations demonstrate the efficiency and high accuracy of the proposed method for investigating vadose zone flow processes. Finally, the photometric procedure has been developed expressly for its extension to heterogeneous media. Other processes may be investigated through different laboratory experiments which will serve as benchmark for numerical codes validation.

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“…Hence, this method allows for the measurement of the degree of saturation of two fluids in a three-phase system (Flores et al, 2011;Kechavarzi et al, 2005;Kechavarzi et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Image analysis method for the measurement of water saturation in a two-dimensional experimental flow tank

Belfort

Weill

Lehmann

2017

Journal of Hydrology

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“…The saturation distributions of water and diesel in the entire flow domain under transient condition are measured by the SIAM (Flores et al, 2011). The two-phase column and Tempe pressure cell data yield soil-liquids characteristic curves (SLCCs) of air/water and air/diesel systems.…”

Section: Discussionmentioning

confidence: 99%

“…The SIAM developed by Flores, Katsumi, Inui, and Kamon (2011) is employed in this research to assess the saturation distributions of water and LNAPL in sand under transient condition. This method is a non-intrusive and non-destructive technique to measure saturations of fluids in porous media in the entire domain of the experimental column.…”

Section: Simplified Image Analysis Methods (Siam)mentioning

confidence: 99%

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Effects of water table fluctuation on diesel fuel migration in one-dimensional laboratory study

Yimsiri

Eua-Apiwatch

Flores

et al. 2016

European Journal of Environmental and Civil Engineering

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The effects of water table fluctuation on diesel fuel redistribution in unsaturated soil are investigated in the laboratory by one-dimensional column test. The simplified image analysis method is used to assess the saturation distributions of water and diesel in the flow domain under transient condition. The experiments are undertaken on two homogeneous sands to study the effects of different particle sizes. The two-phase experimental data illustrate soil-liquid characteristic curves (SLCCs) of water/air and diesel/air systems. The SLCCs of diesel/water systems can be predicted by scaling procedure. A descending order of matric suction at a given saturation of wetting phase is in the order of air/water, diesel/water and air/diesel systems. Coarser particle size gives smaller entry pressure, residual matric suction and residual degree of saturation. The three-phase (air/water/diesel) experimental data illustrate that, during imbibition stages, air and diesel are entrapped below water table with the entrapped air saturations of 18-24% and entrapped diesel saturations of 6-10% for fine sand. Coarser particle size yields smaller entrapped diesel saturations and larger entrapped air saturations. The residual diesel saturations during drainage stages and entrapped diesel saturations during imbibition stages do not show any systematic difference as these stages are repeated. During imbibition stages, 37-47% of the total amount of diesel fuel is entrapped under the water table. Also, there is no systematic difference in the amount of diesel fuel entrapped under the water table when imbibition stages are repeated.

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“…An overview by AGAOGLU et al (2015) found that the laboratory work involved non-destructive and non-intrusive imaging techniques which used characterization and observation of multiphase flow system for greater accuracy. Therefore, a number of researchers (JANINA et al, 2017;SITTHIPHAT & SIAM et al, 2016;PENG et al, 2015;SA'ARI et al, 2015;KAMARUDDIN et al, 2011;NGEIN et al, 2011;FLORES et al, 2011;OOSTROM et al, 2007) have carried out various techniques and methods of non-destructive image analysis for liquid migration experiments. As stated by MAAS & HAMPEL 2006, an image analysis technique in the field of civil engineering was normally used to study the object flow absorption movement in boundary layers and liquid migration of small properties specific to the propagation of structure crack extension, and for this argument, a digital image processing technique was acceptable for use in the study of LNAPL migration in a fractured double-porosity soil.…”

Section: Introductionmentioning

confidence: 99%

Vibration effect influence upon non-aqueous phase liquid migration in double-porosity soil

Rahman¹,

Foong²,

Назир³

et al. 2018

Geol Cro

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Natural disasters such as earthquakes, El-Nino, tsunamis and water pollution have a negative impact on human health and living environment. Some of these may give rise to subsurface vibrations that can potentially increase groundwater pollution risks in double-porosity systems. The more complicated situation was where underground storage tanks and petroleum pipeline damage have caused the leakage of non-aqueous phase liquids (NAPLs) which migrated into the groundwater resources. These problems need to be addressed by both professionals and researchers worldwide to ensure the sustainability of groundwater utilization. This paper aims to investigate and understand NAPL migration in vibrated double-porosity soils. To do so it was necessary to study the phenomena and characteristic of soil structure and the pattern of NAPL migration to identify cost-effective remediation schemes. A laboratory experiment was conducted to study the phenomena and characteristics of vibration response and NAPL migration in double-porosity soil deformation under vibration effect using a digital image processing technique (DIPT). The outcomes of the experiment show that the gradual increase of vibration table excitation frequency yielded different vibration responses from the respective soils. This indicated that soil surface acceleration depended significantly on the soil conditions, soil water content, soil structure and the pattern of soil fracturing. NAPL migration was faster in sample 2 with 150ml toluene than sample 1 with 70ml toluene and this could be because the greater amount of toluene in sample 2 exerted an extra entry force on top of the soil sample that had yet to migrate through the sample surface. Finally, it was concluded that the DIPT may provide detailed information, and can be used to understand and identify the remediation method as well as to ensure the sustainable consumption of groundwater.

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A Simplified Image Analysis Method to Study LNAPL Migration in Porous Media

Cited by 35 publications

References 14 publications

Image analysis method for the measurement of water saturation in a two-dimensional experimental flow tank

Image analysis method for the measurement of water saturation in a two-dimensional experimental flow tank

Effects of water table fluctuation on diesel fuel migration in one-dimensional laboratory study

Vibration effect influence upon non-aqueous phase liquid migration in double-porosity soil

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