Hi, your layout looks ok - although the detailed settings of the models are evidently crucial here.
Please, have a look at the following threads too:
[list]
[li]"Nitrogen removal in SBR"[/li]
[li]"SBR & Desynchronization"[/li]
[/list]
you may find relevant information.
I believe the issue is that you [b]cannot dose anything[/b] to an SBR [b]outside of the "fill" phase[/b] (T1): during all other phases, any inflow is directed to the by-pass. On the other hand, if you replace the data input (which provides a dosage of ethanol during T2R2) by a controller which gives a constant dosage, you may indeed detect some denitrification: but this is because ethanol enter the SBR during T1.
If you really want to feed the SBR during other phases than the fill phase, you need to either modify the base model or consider one of the variants called CFCD or CFID (cf. the threads mentioned above).