Evaluating the Effects of Multiscale Heterogeneous Sediments on Solute Mixing and Effective Dispersion

Ren, Wanli; Ershadnia, Reza; Wallace, Corey D.; LaBolle, Eric M.; Dai, Zhenxue; Barros, Felipe P. J. de; Soltanian, Mohamad Reza

doi:10.1029/2021wr031886

Cited by 13 publications

(7 citation statements)

References 97 publications

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“…Dong et al (2018) suggested that solute transport time and pore-scale geometry control the magnitude of the effect of dispersion; thus, it is assumed that advection-induced flow is homogenous most times, leading to an underestimation of the dispersion coefficient. This was further confirmed by Ren et al (2022), who revealed that at meter-scale heterogeneity, effective dispersion is more sensitive to pore-scale heterogeneity. Solute mixing by hydrodynamic dispersion reflects the heterogeneity of the aquifer at a scale smaller than that associated with the measurement of advection.…”

Section: Frontiers In Environmental Sciencementioning

confidence: 57%

Soil and groundwater contamination by crude oil spillage: A review and implications for remediation projects in Nigeria

Adeniran

Oladunjoye

Doro

2023

Front. Environ. Sci.

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Management of soil and groundwater resources has been recognized as essential to meeting the sustainable development goals of Agenda 2063 of the African Union. As Africa’s fastest growing population with over 200 million people, Nigeria is responsible for leading the continent’s environmental sustainability goal. Nigeria has seen a sizable number of crude oil spillages that have contaminated its soils and groundwater resources, and several of these contaminated sites are to be cleaned up yet. There needs to be more scientific data to design an effective cleanup and to manage the soil and groundwater resources effectively. So far, the only extensive crude oil-contaminated site remediation project documented is on Ogoniland in the Niger Delta region of Nigeria. However, this project resulted in less effective, albeit temporary, cleanup solutions. This review presents a state-of-the-art synthesis of research on soil and groundwater contamination by crude oil. It includes sections on processes, measurements, predictions, and management, as well as an analysis of the state and challenges in Nigeria. In-depth field, laboratory, and computer models for crude oil contamination investigation have been developed with over 60 years of significant research. However, studies and case projects in Nigeria have relied on point sampling to determine the concentration of crude oil contaminants in soil and groundwater. This method offers limited information on the solute concentration and hydraulic distribution, which regulates pollutant mobility within the subsurface. The absence of baseline and high-resolution subsurface characterization data has also resulted in a need for more process-based knowledge to direct the development of site-specific remediation strategies. As a result, it is challenging to design a conceptual model that is detailed enough to help with predictions of the flow dynamics of crude oil contaminants in the unsaturated and saturated zones. It is anticipated that this review will stimulate further multidisciplinary research through site evaluation and monitoring to provide reliable information that can be used to develop appropriate model-based remediation solutions.

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Section: Frontiers In Environmental Sciencementioning

confidence: 57%

Soil and groundwater contamination by crude oil spillage: A review and implications for remediation projects in Nigeria

Adeniran

Oladunjoye

Doro

2023

Front. Environ. Sci.

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“…This information is used to carry out an analysis of the spatial moments of the solute concentration distribution throughout various stages of the experiments. Spatial moment analysis has been proven to be useful measures to describe and analyze the longitudinal spreading of the plumes by, for instance, Trevisan et al and Ren et al Based on our experimental findings, we propose a simplified representation of the mixing process by analogy with the 1D advection-dispersion model. The paper is structured as follows: In section , we introduce the applied materials and the experimental procedure together with the image acquisition and analysis.…”

Section: Introductionmentioning

confidence: 96%

“…By expressing the ratio of density-driven and diffusive mass transport, the dimensionless Rayleigh number, Ra , is commonly used as the basis for the derivation of scaling relationships that predict the occurrence of solutal convection and quantify its strength. Despite it being a fundamental component of convective mixing in porous media, the role of hydrodynamic dispersion is only rarely discussed in experimental studies. − Dispersion can act along the main flow direction (longitudinal dispersion) or perpendicular to it (transverse dispersion), thereby affecting the structure of the downwelling fingers. − Dispersion has been shown to also reduce the onset time of convection and to contribute to the dissolution process in the presence of a background advective flow. , The characterization of DDC in porous media remains challenging and requires the development and application of advanced laboratory protocols to unravel the evolving concentration field in the medium.…”

Section: Introductionmentioning

confidence: 99%

Spatial Moment Analysis of Convective Mixing in Three-Dimensional Porous Media Using X-ray CT Images

Anna-Maria

Liyanage

Kurotori

et al. 2022

Ind. Eng. Chem. Res.

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Dissolution trapping is one of the primary mechanisms of carbon dioxide (CO2) storage in deep saline aquifers. The determination of the realized rates of CO2 dissolution requires an understanding of the mixing process that takes place following the emplacement of CO2 into the formation. Owing to the difficulty of reproducing the time-dependent convective process in porous media, experiments so far have largely focused on 2D systems (e.g., Hele-Shaw cells) and used analogue fluid pairs with properties that differ from the subsurface CO2/brine system. Here, we present a novel experimental approach to investigate the evolution of the convective mixing process in 3D porous media (homogeneous packings of glass beads) using X-ray computed tomography (CT). We explore a range of Rayleigh numbers (Ra = 3000–55000) and observe directly the mixing structures that arise upon dissolution. We compute from the images the temporal evolution of the spatial moments of the concentration distribution, including the cumulative dissolved mass, the location of the center of mass, and the standard deviation of the concentration field. The scalings of the spatial moments suggest an impact of hydrodynamic dispersion on the longitudinal mixing. We propose a simplified representation of the mixing process by analogy with the 1D advection–dispersion model. This enables the estimation of the bulk advective velocity and the effective longitudinal dispersion coefficient for each bead packing. These estimates suggest that the presence of the finger pattern and the counter-current flow structure enhance the longitudinal spreading of the solute by roughly 1 order of magnitude compared to unidirectional dispersion of a single-solute plume.

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“…(8,9) Adsorption and dispersion processes form the basis of modeling crude oil contaminants in groundwater pollution. (10) Many studies have shown the impact of crude oil spills on the soil and their seepage into groundwater. Some researchers focused on assessing the quality of groundwater in the study area (Nigeria) with the aim of ascertaining the nature and extent of the effects of the oil spill on that water.…”

Section: Introductionmentioning

confidence: 99%

Environmental Impact of Petroleum Refinery Effluent on Groundwater Pollution: A Case Study of Maysan Refinery, Iraq

M. Khalefah,

Omran,

Al-Waily

2024

Salud, Ciencia y Tecnología - Serie de Conferencias

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The study aimed to investigate the environmental impact of the refinery's wastewater on groundwater within the refinery and the surrounding area. Six different testing sites were chosen to measure the concentrations of groundwater pollutants according to their distance from the untreated oil effluent discharge lagoon. The study period lasted for six months, as the testing work began in April and ended in September 2023. The results showed a clear effect of untreated petroleum effluent on the properties of groundwater, as the concentrations of petroleum effluent (oil and grease, TOC, phenol) and heavy metals (Ni, Cd, Pb) exceeded the permissible limits, as well as related parameters (TDS, EC, Cl, SO4) according to WHO specifications. As for the concentrations of the parameters (BOD, COD), there was no clear effect of the effluent on them, and on the contrary, their values began to increase at the testing sites far from the refinery. The groundwater was greatly affected by a distance of 5 km from the effluent collection lagoon (testing sites:GW1, GW2, GW3, and GW4), and it was not suitable for human use until after it was treated. As for the remaining of the distance (testing sites:GW5, GW6) to the nearest residential area (from 5 km to 9 km), the groundwater was limited to use for irrigation according to WQI guidelines. The study recommends that, in order to reduce pollution of refinery effluent, the responsible administration should use regular wastewater networks, construct a treatment plant for this effluent, and discharge the treated effluent to the nearest water source

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Evaluating the Effects of Multiscale Heterogeneous Sediments on Solute Mixing and Effective Dispersion

Abstract: Accurate representation of solute transport processes (e.g., dispersion, mixing, and dilution) is important for various porous media-related applications such as hydrogeology, soil physics, environmental engineering and sciences, water resources management, and petroleum engineering (de

Cited by 13 publications

References 97 publications

Soil and groundwater contamination by crude oil spillage: A review and implications for remediation projects in Nigeria

Soil and groundwater contamination by crude oil spillage: A review and implications for remediation projects in Nigeria

Spatial Moment Analysis of Convective Mixing in Three-Dimensional Porous Media Using X-ray CT Images

Environmental Impact of Petroleum Refinery Effluent on Groundwater Pollution: A Case Study of Maysan Refinery, Iraq

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