Estimation of contaminant transport parameters for a tropical sand in a sand tank model

Ojuri, Oluwapelumi O.; Ola, S. A.

doi:10.1007/bf03326148

Cited by 21 publications

(11 citation statements)

References 29 publications

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“…Medium-grained sand (i.e., ''16-30'' grade sands, Sloan Sands P/L, Dry Creek, South Australia) was the porous medium used in the experiments. A wet-packing method was adopted to obtain a relatively uniform level Water Resources Research 10.1002/2015WR017098 of compaction and minimal entrapped air [Ojuri and Ola, 2010]. Porosity (n) of the sand was measured by the water saturation method [Fetter, 2001] and found to be 0.41.…”

Section: Laboratory Experimentsmentioning

confidence: 99%

Water table salinization due to seawater intrusion

Badaruddin

Werner

Morgan

2015

Water Resources Research

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Seawater intrusion (SWI) is a significant threat to freshwater resources in coastal aquifers around the world. Previous studies have focused on SWI impacts involving salinization of the lower domain of coastal aquifers. However, under certain conditions, SWI may cause salinization of the entire saturated zone of the aquifer, leading to water table salinization (WTS) in unconfined aquifers by replacing freshwater within the upper region of the saturated zone with seawater, thereby posing a salinity threat to the overlying soil zone. There is presently limited guidance on the extent to which WTS may occur as a secondary impact of SWI. In this study, physical experiments and numerical modeling were used to explore WTS associated with SWI in various nontidal, unconfined coastal aquifer settings. Laboratory experiments and corresponding numerical simulations show that significant WTS can occur under active SWI (i.e., the freshwater hydraulic gradient slopes toward the land) because the cessation of freshwater discharge to the sea and the subsequent landward flow across the entire sea boundary eventually lead to water table salinities approaching seawater concentration. WTS during active SWI is larger under conditions of high hydraulic conductivity, rapid SWI, high dispersivity and for deeper aquifers. Numerical modeling of four published field cases demonstrates that rates of WTS of up to 60 m/yr are plausible. Under passive SWI (i.e., the hydraulic gradient slopes toward the sea), minor WTS may arise as a result of dispersive processes under certain conditions (i.e., high dispersivity and hydraulic conductivity, and low freshwater discharge). Our results show that WTS is probably widespread in coastal aquifers experiencing considerable groundwater decline sustained over several years, although further evidence is needed to identify WTS under field settings.

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Section: Laboratory Experimentsmentioning

confidence: 99%

Water table salinization due to seawater intrusion

Badaruddin

Werner

Morgan

2015

Water Resources Research

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“…Clement et al (2004) studied the transport of chlorinated solvents in a biologically reactive medium by conceptualizing dissolution process as mass-transfer limited reaction, sorption as a rate-limited process and biodegradation as a kinetic-limited process. Ojuri and Ola (2010) conducted laboratory experiments in a saturated sand tank to investigate transport and natural attenuation of BTEX compounds. A 3-D finite difference numerical model was developed to model advection, dispersion and reaction of BTEX compounds.…”

Section: Introductionmentioning

confidence: 99%

Interaction of dissolution, sorption and biodegradation on transport of BTEX in a saturated groundwater system: Numerical modeling and spatial moment analysis

Valsala

Govindarajan

2018

J Earth Syst Sci

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Interaction of various physical, chemical and biological transport processes plays an important role in deciding the fate and migration of contaminants in groundwater systems. In this study, a numerical investigation on the interaction of various transport processes of BTEX in a saturated groundwater system is carried out. In addition, the multi-component dissolution from a residual BTEX source under unsteady flow conditions is incorporated in the modeling framework. The model considers Benzene, Toluene, Ethyl Benzene and Xylene dissolving from the residual BTEX source zone to undergo sorption and aerobic biodegradation within the groundwater aquifer. Spatial concentration profiles of dissolved BTEX components under the interaction of various sorption and biodegradation conditions have been studied. Subsequently, a spatial moment analysis is carried out to analyze the effect of interaction of various transport processes on the total dissolved mass and the mobility of dissolved BTEX components. Results from the present numerical study suggest that the interaction of dissolution, sorption and biodegradation significantly influence the spatial distribution of dissolved BTEX components within the saturated groundwater system. Mobility of dissolved BTEX components is also found to be affected by the interaction of these transport processes.

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“…Several laboratory studies used the sandbox device to validate and verify their numerical models (Armanyous et al, 2016;Basha et al, 2009), to estimate pollutant transport parameters for a tropical sand (Ojuri & Ola, 2010), to study the flow net, to estimate values of uplift pressure underneath a hydraulic structure, and to determine the best inclination angle of the cutoff (45°) in order to reduce both the uplift pressure and the quantity of seepage (Alghazali & Alnealy, 2015). A combination of flow barrier and freshwater injection in unconfined coastal aquifer systems, when simulated using the sandbox, proved valid to force the saltwater to retreat with a greater repulsion ratio than either of them separately (Armanuos, Ibrahim, Mahmood, Takakura, & Yoshimura, 2019).…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental analyses of the use of double vertical barrier walls for groundwater protection

Mostafa

Gado

Masoud

et al. 2020

Water Environment Research

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The groundwater contamination and its impacts on the hydrologic systems and society are critical environmental concerns in the world. This research presents insights from the numerical (SEEP/W and CTRAN/W) and the experimental (sandbox model) analyses of the use of double vertical barrier walls for groundwater protection. The main objective was to evaluate contaminant transport under the effect of several variables. The arrival time increases with increasing the distance between the pollutant source and the first wall, first wall depth of penetration, the distance between the two walls and also increases at smaller hydraulic head differences, and lower conductivities. Furthermore, using double barrier walls would significantly reduce contaminant concentration at the downstream area. This control is most significant when the depth of first wall penetration is larger than that of the second wall. Results proved consistent with several similar studies and advantageous over many of them by the integrated use of both techniques with more variable parameters evaluated. © 2020 Water Environment Federation • Practitioner points • The research will introduce insights from the effect of using double barrier walls on the hydraulic control of contaminant transport. • The effect of several variables on the contaminant arrival time and concentration is investigated. • Using double barrier walls has a significant impact on contamination transport through the soil. • This control is most significant when the penetration depth of the first wall is larger than that of the second.

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Estimation of contaminant transport parameters for a tropical sand in a sand tank model

Cited by 21 publications

References 29 publications

Water table salinization due to seawater intrusion

Water table salinization due to seawater intrusion

Interaction of dissolution, sorption and biodegradation on transport of BTEX in a saturated groundwater system: Numerical modeling and spatial moment analysis

Numerical and experimental analyses of the use of double vertical barrier walls for groundwater protection

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