Contaminant transport through fractured-porous media: An experimental study

• Solute transport experiment is carried out in fractured-porous media in the lab.
• We examine the presence of diffusion and sorption in the fracture.
• Higher value of diffusion decreases the solute concentration in the fracture.
• Higher value of sorption decreases the solute concentration in the fracture.
• Behavior of time moments is nonlinear along travel distance.

In this paper, an experimental study has been carried out to investigate the behavior of solute transport through fractured-porous media. Experimental set-up consists of fractured-porous media which has been created with clay (matrix) and a single fracture is created in middle of the clay matrix in flow direction. During experiment, the clay matrix is saturated with fresh water and solute tracer is injected in the fracture at inlet and the samples are collected from out let for different times of interval. Concentration profiles of experimental data of chloride and fluoride are simulated with developed numerical model to estimate transport parameters. Results show that the value of matrix-diffusion coefficient depends on fracture velocity and residence time till to reach in equilibrium condition. It is also found that higher value of diffusion coefficient leads to reduce the magnitude of solute concentration in the fracture. The experimental results indicate that there is substantial diffusion and sorption in the fractured-porous matrix. The estimated parameters and numerical model can be used for design of waste disposal system in the fractured matrix system. Finally, numerical results of various temporal moments have been predicted to study the behavior of reactive solute in the fracture, and it was found that the behavior of solute mass recovers, mean arrival time and second time moment are nonlinear along the travel distance for solute in the fracture in the presence of matrix-diffusion and decay rate coefficient.