Can I use CXTFIT to model my system?

adhikariumesh · Post by **adhikariumesh** » Wed Oct 12, 2011 2:47 am

Hello,
I am working on pathogen removal in constructed wetlands. My wetland is a two stage wetland: surface flow+subsurface flow, two separate systems. I pulse the first wetland with pathogen and collect sample from the outlet. I used CXTFIT chemical nonequilibrium model with pulse input to model the system. I have also collected data from the outlet of the second wetland. My problem is the second one: output from the first one is the input to the second one. Is there any way I can use CXTFIT to model second wetland, independent of the first? If so, what type of input should I use in CXTFIT?
Thanks a lot
Umesh

Jirka · Post by **Jirka** » Wed Oct 12, 2011 2:53 am

Umesh,

I do not think that you can use CXTFIT to model a system, in which you actually have two different layers (stages) with different properties. However, there should be no problem of using HYDRUS for this. In HYDRUS you can specify multiple observation nodes (in your case two) and multiple soil horizons with different properties. You can fit parameters for both of these horizons simultaneously (especially if you have two BTC - at the interface and at the end of the system).

Jirka

adhikariumesh · Post by **adhikariumesh** » Thu Oct 13, 2011 4:59 pm

Hello Dr. Jirka,
I am now modeling first wetland. Just a quick question: I am taking the sample from the outlet of my wetland. What is my "Position of the Breakthrough Curve"? Is it the time at which I obtain the peak? I use dimensionless position and dimensional time.

Thank you
Umesh

Jirka · Post by **Jirka** » Thu Oct 13, 2011 5:39 pm

I do not provide help on CXTFIT (outside of my area of expertise). j.