Low nitrogen removal?

[moved from "A block (flow splitter) does not receive input?"]

The existing problem now is no Nitrogen removal in the model i.e  less than 10%, I checked the recirculation of flow from deoxic tank to anoxic tank and size of the tanks.  I wonder why? the model works well on removal of COD and TP but not Nitrogen. In the model input, TKN is directly connected to S_NH with fraction ratio of 0.4. Is it possible to fractionate TKN to Org_N and S_NH by using ASM2d?

[quote author=Enrico Remigi link=topic=2492.msg5794#msg5794 date=1433928607]
.. Nitrogen removal in the model i.e  less than 10%, ..
[/quote]

Is it not that you aerated too much (what's the DO in the tanks, especially anoxic)?
Or that you recycle too much of the aerated mixed liquor?

[quote author=Enrico Remigi link=topic=2492.msg5794#msg5794 date=1433928607]
Is it possible to fractionate TKN to Org_N and S_NH by using ASM2d?
[/quote]

Absolutely! The (de)fractionation models (layouts) that are shipped with WEST are only basic options that one can use. But you can certainly modify them  (or create completely new ones) and save them.
Please see another thread on this forum.