Enrico Remigi WEST Product Owner

Q_Under is non-zero only in period T5 when it is set equal to the parameter Q_Waste (if the tank is not empty)

Sure, it's possible. In fact, this is not specific to leachate at all and is applicable to the generic situation where one needs to model a toxic/inhibitory effect.

You will probably need to add a toxic or inhibitory component (e.g. S_Tox) to the component vector of your modified category (e.g. ASM1_Tox). Assuming you don't want to do all this manually, you can add a component through the "Manage Components" button in the Matrix Editor.
Then you can certainly define a state variable (at the category level, so again: through the Matrix Editor | Variables tab page) - as well as the relevant parameters used in the expression of the new state variable.
And finally: include the state variable in the kinetic expression of the relevant processes.

It may also be that the interval for the OBJ is not set directly within the OBJ's definition but "inherited" through its data type, e.g.:
---
OBJ Epsilon "Efficiency of the motor": Efficiency := {: value <- 0.58 ; group <- "Power consumption" :};
---
If this is the case, you obviously need to change Lower/Upper Bounds of the OBJ Efficiency - hold the Ctrl key down and hover over the word 'Efficiency': an hyperlink will appear, click and it will take you to the OBJ's definition

You need to modify the value(s) at the level of the model, using the Model Editor

[quote author=I.Totaro link=topic=1471.msg3612#msg3612 date=1370682008]
I would like to make some plots with the perturbation of the parameter on x-axis and the function of sensitivity on y-axis.
[/quote]

I am afraid this is not directly possible. You have the following options when creating a plot (AddSeries button):
- [b]Sens[/b]: typically, you would plot the "RunNo" (x-axis) vs. one of the sensitivity quantities (e.g. CRS, Central Relative Sensitivity; y-axis)
- [b]SensFunc(ParName)([VarName])[/b]: typicall, "t" vs. one of the sensitivity quantities (y-axis)
- [b]Simul(Ref)[/b]: same as the plain Simul, i.e. "t" vs. one of the data series
- [b]Simul([Backward OR Forward])([ParName])[/b]: same as Simul(Ref)

What you may have in mind is some sort of Scenario Analysis where you compare the use of different perturbation factors?

[quote author=I.Totaro link=topic=1471.msg3612#msg3612 date=1370682008]
I would like also to plot the perturbed trajectories and the nominal trajectory for each parameter.
[/quote]

This should be possible: one data series being Simul(Ref), the other one(s) Simul([Backward OR Forward])([ParName])

[quote author=I.Totaro link=topic=1471.msg3612#msg3612 date=1370682008]
Then I would also like to define a ranking of sensitivity by the various parameters, so I can choose which ones I must calibrate.
[/quote]

Is this not what one would typically do in a [b]Global[/b] Sensitivity Analysis rather? In GSA, you have what we termed "Tornado" plots which compare the sensitivities of a variables to a set of parameters. There you could establish a threshold: anything beyond that is worth calibrating.

I would say it has to do with some path names that are invalid or not properly set, or relative references that are invalid.
Could you please email our technical support (mikebydhi@dhigroup.com) - simply refer to this post, no need to rewrite everything; only send the Diagnostics (Tools menu) along.

I am not familiar with the peculiarity of a "T type" oxidation ditch, but I have seen implementations of oxidation ditches in WEST, yes.
You could probably use a Continuous Flow-Intermittent Decanter (CFID) block and a Timer/Controller to switch phases. It may also need some careful modeling of the phase change to avoid hard switches that would slow down the integrator.

Once again, the procedure you follow sounds correct. I usually do the following:
1) open the BlockLib.xml
2) open the Gujer Matrix editor for the Category which is most similar to the one you plan to create
3) do all the relevant modifications (add components, processes, parameters, ...)
4) close the matrix editor
5) when asked for the category name, provide a different name - otherwise you will overwrite the existing category
This process will create the necessary msl files, add the relevant include statements and create a new Model Instance with the same name as your new Model Category (by default)
6) close and save the BlockLib.xml