AI Article Synopsis
- Understanding back diffusion of contaminants from low-permeability zones to aquifers is crucial for effective site management and remediation efforts.
- The study introduces a three-stage classification of contaminant plume life cycles based on their origins: 1) aquifer source zone dissolution, 2) combined source zone dissolution and back diffusion, and 3) only back diffusion.
- Data from multiple field sites helped identify distinctive concentration profiles, allowing for the development of analytical models that can assist site managers in selecting appropriate remediation strategies based on the contamination stage and permeability zones.
Article Abstract
Understanding the effects of back diffusion of groundwater contaminants from low-permeability zones to aquifers is critical to making site management decisions related to remedial actions. Here, we combine aquifer and aquitard data to develop recommended site characterization strategies using a three-stage classification of plume life cycle based on the solute origins: aquifer source zone dissolution, source zone dissolution combined with back diffusion from an aquitard, and only back diffusion. We use measured aquitard concentration profile data from three field sites to identify signature shapes that are characteristic of these three stages. We find good fits to the measured data with analytical solutions that include the effects of advection and forward and back diffusion through low-permeability zones, and linearly and exponentially decreasing flux resulting from source dissolution in the aquifer. Aquifer contaminant time series data at monitoring wells from a mature site were well described using analytical solutions representing the combined case of source zone and back diffusion, while data from a site where the source had been isolated were well described solely by back diffusion. The modeling approach presented in this study is designed to enable site managers to implement appropriate remediation technologies at a proper timing for high- and low-permeability zones, considering estimated plume life cycle.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.jconhyd.2017.05.001 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Impact of the Marangoni phenomenon on the different Enhanced Oil Recovery methods.
Heliyon
November 2024
Department of Petroleum Engineering, Faculty of Petroleum, Gas, and Petrochemical Engineering, Persian Gulf University, Bushehr, Iran.
The occurrence of the Marangoni phenomenon is due to the surface tension gradient within a system, resulting in the creation of a convective flow from low surface tension to high surface tension points. This phenomenon arises from changes in solvent concentration, temperature and electric charge. In the context of the enhanced oil recovery (EOR) process, changing solvent concentration at the interface of two fluids in matrix fracturing systems caused by gas injection (in immiscible, immiscible and near-miscible conditions) and surfactant flooding, can enhance oil recovery by increasing the Marangoni effect.
View Article and Find Full Text PDFPropagation behavior of coal crack induced by liquid CO2 phase change blasting considering blasting pressure effects.
PLoS One
November 2024
College of Aerospace Engineering, Chongqing University, Chongqing, China.
To investigate the crack propagation mechanisms in low-permeability coal seams induced by liquid CO2 phase change blasting under different blasting pressures, this research presents an experimental study conducted on a small liquid CO2 phase change blasting test system. The failure mode, crack morphology, and distribution characteristics of the coal rock model specimens under different liquid CO2 phase change blasting pressure were revealed, analyzing the crack shapes and expansion process. The results show that with increasing blasting pressure, both the number and complexity of cracks significantly increase under liquid CO2 phase change blasting, evolving from simple linear cracks to more complex multi-directional networks.
View Article and Find Full Text PDFContrast of hydraulic conductivity induces transport of combined pollutants in high- and low-permeability systems.
Ecotoxicol Environ Saf
November 2024
Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address:
The transport process of pollutants in the environment can be influenced by heterogeneous geologic architecture and pollutant interactions. However, there has been a lack of research on co-transport behaviors of combined pollutants in heterogeneous aquifers. In this study, a series of two-dimensional tank experiments were carried out to study the transport behavior of toluene and naphthalene in both homogeneous and heterogeneous aquifers.
View Article and Find Full Text PDFA numerical investigation to assess changes to displacement front and by-passed zones employing kinetic interface-sensitive tracer.
J Contam Hydrol
November 2024
Department of Applied Geology, Geoscience Centre of the University of Göttingen, Goldschmidtstr. 3, 37077, Göttingen, Germany.
An important aspect in groundwater remediation is to understand changes of multiphase fluid front morphology and stagnant regions on macro scale. However, the prediction of those changes during two-phase flow remains a challenging task due to the interplay of various physical factors. Recent laboratory experiments have demonstrated tracers' ability to predict deformation in the front of a two-phase flow system by utilizing a new reactive tracer known as, the kinetic interface sensitive tracer (KIS).
View Article and Find Full Text PDFThe impact of lenses on the seepage failure of tailings dam.
PLoS One
August 2024
China Academy of Safety Science and Technology, Beijing, China.
The presence of lenses such as tailings slurry, frozen soil, and saturated zones disrupts the continuity of tailings dams and their normal seepage patterns, elevating the seepage line of the dam body and significantly impacting local stability. This study, to investigate how lenses affect the stability and failure mechanisms of tailings dams, employs numerical simulation and physical models and constructs a model of the tailings dam, incorporating tailings clay lens and void lens, to investigate variations in hydraulic gradients, seepage velocities, seepage flow, pore water pressure, and the patterns of seepage failure. This research reveals that the tailings clay lens within the dam body increases the hydraulic gradient in its vicinity due to its low permeability and raises the phreatic line.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!