I had set-up a pretreatment of leachate using limestone. Column is set vertically with leachate flowing from bottom to top of the column. Given that the radius and height of the column are 0.075m and 1.2m respectively. Time for the leachate to retain in the column is 30 minutes. Can I use the basic formula of volume flow rate, q=V/t?
in steady-state flow, the flow rate of any liquid in porous rock (at low velocities) is given by Darcy's
https://en.wikipedia.org/wiki/Darcy's_law
However this situation might not be really given in your case, because you say that you do retain the leachate over 30 minutes. That sounds more like you are doing a tracer flow experiment and have an unsteady flow situation from a solute transport point of view, and therefore need to consider a convection-diffusion equation
https://en.wikipedia.org/wiki/Convection%E2%80%93diffusion_equation
which in a porous media context becomes more a convection dispersion equation. If your leachate reacts with the limestone, then we are actually talking about a reaction-diffusion-convection problem
https://en.wikipedia.org/wiki/Reaction%E2%80%93diffusion_system
where you need to know the reaction rate. However this becomes a much more complex problem, as depending on your flow regime different things can happen that determine your breakthrough curve.
So to be honest, I would start to check how you are doing with a convection-diffusion equation and compare your experimental measurements with the estimate from the convection-dispersion equation. For that you need to know what the permeability of the rock is, and that you can estimate from Darcy's law by applying a constant flow rate and measuring the pressure drop, or vice versa. so in your case you apply a constant gravity head, i.e. a constant pressure drop. But first do this with a non-reacting fluid, i.e. a brine compatible with your rock.
you can calculate flow with measurement volume and height of the column and time leachate stand
- Badges
- Science method