Calibrated parameters far from standard bibliography values

Good afternoon,
I am doing the parameter calibration experiment for heterotrophic biomass (muH, KS and YH), considering two fracture schemes of the effluent.

The quality results of the treated effluent are satisfied.

However, the calibrated muH and YH parameters are not close to the standard values of the bibliography (the calibrated temperature);

In case of admitting, for example (TSS / XCOD = 0.75), I am having a result of parameter YH calibrated near zero, and muH a value of 11 (which is far from the default value 6, at = 20 ° C );

By admitting the fractionation TSS / XCOD = 0.53. The calibrated YH parameters assume a value close to 1 (YH = 0.98);

Do you find normal, these results of the calibrated parameters?

Thank you,
Luís

Not at all !
Those values are completely unrealistic.
I cannot say what may go wrong because I don't know what your process looks like or the data you are using, I can only speculate.
If you are talking about alternatives for the influent fractionation (the COD to TSS conversion), I assume you are attempting to calibrate a (complex or not) process model only based on influent data. This is a 'dangerous' approach which is bound to result in completely awkward estimates of kinetics parameters - the relation between those and the influent specs is kind on loose ...
You should first calibrate your influent model to make sure that you feed your process with a [b]'correct' influent[/b]; then you should probably look at the steady-state behaviour of your system (sludge age, MLSS, etc.); and only then, if necessary and if you have data to support that, calibrate the kinetic model.
I don't know which data you have for your influent (e.g. COD, TSS, TN, .. ? BOD, TSS, .. ? rbCOD, ..? several combinations are possible), but you need to perform, at least (!) some continuity checks.
For instance: if you have COD and TSS and derive soluble and particulate COD based on F_TSS_COD (the standard fractionation in WEST), you need to make sure that the [b]calculated BOD[/b] (combination of COD components that contribute to BOD) is reasonable, i.e. 2-2.5 or so COD / BOD; or even better, if you have a BOD measurement as well, close enough to your measurement.

Hello Enrico,

Joining to the discussion ... when you mention BOD are you refering to "DO comsumption after 5 days" or b(iochemical)COD?

In WEST and using the standard fractionation, bCOD is approximately S_S + X_S + X_BH?

Thank you,
João

I mean Biological or Biochemical Oxygen Demand.
Yes, in ASM1, BOD is the combination of S_S, X_S and part of X_BH, X_BA.

Yes, the calibration I am doing, the objective function is by mean difference (TSS and COD parameters of the treated effluent);

The effluent input data are: COD, BCOD, TKN and water, and I am using the standard WEST fractionation;

I considered the BCOD = 0.85 * COD input, what do you think? (That may be what is influencing the results.

Questions / Doubts:
A) The COD / BOD ratio you are talking about, the BOD is the total, or the first five days, or the first few days?

For the BOD data I have in hand, they are BOD for the first five days;

B) I saw a work in which the input fractionation scheme is similar to the standard fractionation scheme of the WEST, however, it had a connection of TSS and X_TSS with a ratio of 1. This has some difference with the fractionation scheme WEST standard?

Thank you
Luís

You write BCOD and BOD: I am confused ...
If 0.85 is BOD / COD, I would say it is rather high.

[quote author=Luís Roque Silva Lopes link=topic=20169.msg26050#msg26050 date=1496276209]
A) The COD / BOD ratio you are talking about, the BOD is the total, or the first five days, or the first few days?
[/quote]
I would say BOD5

[quote author=Luís Roque Silva Lopes link=topic=20169.msg26050#msg26050 date=1496276209]
B) I saw a work in which the input fractionation scheme is similar to the standard fractionation scheme of the WEST, however, it had a connection of TSS and X_TSS with a ratio of 1.
[/quote]
When you say "standard fractionation scheme of WEST", I presume you are referring to the ASM1 fractionation model.
X_TSS is a component of ASM2(dModTemp), which is equally "standard".

Bottom line is: if you have BOD measurements as well, you need to ensure that the '[b]calculated BOD[/b]' is as close as possible to your measurements; or in fact, the ratio close to 1.

Thank you,

We already perceive the scheme of reasoning that we have to do;

Just one more thing, do you know which is the affluent X_BH fraction in the residual domestic water?

Thank you,
Luís

I would guess 10-15% of the particulate COD, or less

Hello,

Regarding "BOD is the combination of S_S, X_S and part of X_BH, X_BA."

Is there some approximate value for part of X_BH contributing to bCOD? 

Thank you,
João