I am trying to model DBP (TTHM & HAA5) formation in WaterCAD. I've added both as constituents, and I've got lab results that I can use to estimate the reaction coefficient and max. concentration level to input into WaterCAD. Are there standard diffisuvity values for these DBP's? And is it most conservative to model these with zero wall reaction? Any thoughts would be appreciated. Thanks.
Usually, it's good to start off with zero wall reaction rates and then adjust those rates if you think it will improve calibration.
I don't know of a good value for dififusivity of THM's. However, as the wall reaction rate increases, the importance of diffusivity decreases. You can do some sensitivity analysis to see how much difference it makes in your model.
Answer Verified By: Jesse Dringoli
Tom,
I've got my parameters input on the constituent. The constituent alternative is called out in my scenario along with the constituent calculation option, but I'm still showing 0 mg/L concentration at all points in the model over the time period. I suspect something is not set up right in the Constituent Alternative either, most likely at the reservoir where my DBP formation would initiate. Any thoughts?
Thanks,
Adam
There are no reactions in a resrvoir node. It is just a constant head. You would need to model it as a tank element.
Never mind. I think I am finally seeing some results. They just need to be calibrated now. Thanks.