Dense, viscous brine behavior in heterogeneous porous medium systems
D Johnson Wright1, J A Pedit, S E Gasda
1Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599-7431, USA.
Journal of Contaminant Hydrology
|May 7, 2010
Summary
Dense, viscous calcium bromide brine solutions can effectively remediate dense nonaqueous phase liquid (DNAPL) contamination. Laboratory and field studies confirm that these brine layers can be established, maintained, and recovered for reuse.
Area of Science:
- Environmental Engineering
- Hydrogeology
- Chemical Engineering
Background:
- Dense nonaqueous phase liquids (DNAPLs) pose significant environmental contamination challenges.
- Remediation strategies often require specialized fluid solutions to manage contaminant behavior.
- Calcium bromide brine solutions are investigated for their potential in DNAPL remediation.
Purpose of the Study:
- To investigate the physical properties (density, viscosity) of calcium bromide brine solutions.
- To evaluate the effectiveness of dense brine layers in DNAPL remediation in laboratory and field settings.
- To assess the establishment, persistence, and recovery of brine layers for potential reuse.
Main Methods:
- Experimental determination of brine density and viscosity across various mass fractions.
- Laboratory-scale experiments using a 3D cell to study brine layer dynamics.
- Field-scale experiments at the Dover National Test Site.
- Modification and application of the SUTRA groundwater flow simulation code.
Main Results:
- Calcium bromide brine solutions achieve high density (1.7x water) and viscosity (6.3x water) at 0.53 mass fraction.
- Dense brine layers were successfully established, maintained, and recovered in both lab and field experiments.
- Unstable density profiles were observed in field experiments, linked to low hydraulic conductivity zones.
- Standard SUTRA model formulations were inadequate for simulating sharp density gradients in brine experiments.
Conclusions:
- Dense calcium bromide brine layers are a viable component for DNAPL remediation strategies.
- Successful recovery of high-mass-fraction brine supports economical reuse, enhancing remediation sustainability.
- Further model development is needed to accurately capture variable-density flow with sharp gradients.
Related Concept Videos
01:17Viscosity
When water is poured into a glass, it falls freely and quickly, whereas if honey or maple syrup is poured over a pancake, it flows slowly and sticks to the surface of the container. This difference in the flow of different kinds of liquids arises due to the fluid friction between the liquid layers and the liquid and the surrounding material. This property of fluids is called fluid viscosity. In this example, water has a lower viscosity than honey and maple syrup.
The SI unit of viscosity is...
The SI unit of viscosity is...
01:27Viscosity
Viscosity is a property of fluids that measures their resistance to flow. It is influenced by factors such as the surface area of contact, the gradient of flow speed, and the fluid's viscosity constant, called the coefficient of viscosity. The coefficient of viscosity, also known as dynamic viscosity, is denoted by the symbol η. It determines the proportionality between the viscous force and the gradient of flow speed.Newton's law of viscosity states that the viscous force on a faster-moving...
01:19Viscosity of Fluid
Viscosity measures the resistance a fluid offers to flow and deformation. It results from internal friction between layers of fluid moving relative to one another. Dynamic viscosity, denoted by the Greek letter mu (μ), quantifies the force needed to move one fluid layer over another. For Newtonian fluids like water and air, the relationship between the shearing stress and the rate of shearing strain is linear, meaning their viscosity remains constant regardless of the applied stress.
02:57Surface Tension, Capillary Action, and Viscosity
Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
01:18Newtonian Fluid: Problem Solving
Newtonian fluids exhibit a constant viscosity, meaning their shear stress and shear strain rate are directly proportional. This property ensures a predictable and stable response to applied forces, maintaining a linear relationship between force and flow. Examples include water, air, and light oils, consistently demonstrating this proportional behavior regardless of external conditions.
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
A velocity gradient forms within the fluid when a Newtonian fluid is placed between two parallel plates, with...
01:20Stokes' Law
Viscous forces, like friction, are intermolecular forces that resist the relative motion of molecules over each other. When a solid body moves through a liquid, viscous forces drag it in the opposite direction. The force's magnitude depends on the solid's shape and size, as well as its speed and the liquid's coefficient of viscosity, density and temperature.
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only for low Reynolds...
The expression for the force on a solid spherical object in a fluid is called Stokes' law. Stokes' law is valid only for low Reynolds...