Functionality for adsorption/desorption mechanism in wetlands using OGS-Phreeqc

Usability
1

Hi all. I’ve configured a vertical flow wetland simulation with pulsed inflow using the OGS-Phreeqc tutorial as a template and am now at the point where I need to represent the adsorption/desorption mechanism for NH4-N, which is important for nitrification during the resting phase in VFWs operation.

Having read through recent papers on VFW and horizontal flow wetland simulation with OGS-Phreeqc, I know that this adsorption/desorption functionality has been implemented, but am not sure where/how to access it.

Could anyone perhaps please point to an example of how the OGS-Phreeqc files can or should be changed to represent the adsorption/desorption functionality.

2

Hi wkamish,

Thanks for your interest in using OGS6#Phreeqc for your study. If you would like to simulate mechanistic sorption/desorption mechanism with Phreeqc, you may take a look at the radionuclide sorption example (Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/SurfaceComplexation · master · ogs / ogs · GitLab).

Best regards,
Renchao

3

Hi @wkamish ,

the mentioned OGS#Phreeqc tutorial uses OGS5.
In the context of simulating constructed wetlands, a kinetic adsorption/desorption process for NH4N as used in Boog et al. (2019) was implemented as a kinetic reaction in Phreeqc using the KINETICS and RATES keywords.

Have a look at this model as an example of a horizontal flow wetland:
model.zip (34.6 KB)

4

Thanks for that @johannes.boog. I will have a look at it and follow-up if any further questions arise.
Regards
Wageed

5

Thanks @renchao.lu. I’ll have a look.
Regards
Wageed