SBR & Desynchronization

Hello,

In a SBR system, probably I have a kind of desynchronization with the different timers that I have used. I have two SBR reactors, with alternative feed of wastewater of 3 hours lenght for the fill phase in each one (and other 3 hours lenght for the rest of phases). In SBR_1 the water flows correctly by the Q_out, but in the second one (SBR_2), the wastewater flows by the Q_bypass. How can I indicate to the SBR_2 that its fill phase starts 3 hours later than the fill phase in the SBR_1? As far as I understand, I can only indicate the length of the different phases, but I do now find the way to indicate when the fill phase starts….

In addition, the SBR_1 cannot make growth its X_TSS more than 108 ppm, despite it seems to work correctly….but maybe this strange behavior could be solved after the mentioned one before.

Thanks for your time.

There may be two ways to achieve what you're asking:
[list]
[li]you could probably make use of the parameter "[b]T_Launch[/b]" and set to 0 for the first tank and 3h for the second tank; or[/li]
[li]use a [b]timer to control the feed[/b] to the tanks, e.g. connected to a fraction splitter that directs the flow to either tank every 3h[/li]
[/list]

Hi Enrico,

Thanks for your quick and efficient reply. With your answer I have solved the desynchronization problem, but I am afraid that something else I am doing wrongly because there are two strange effects that I tell you below,  just in case them could give you a clue about where can be my mistakes:

• X_TSS do not grow more than 400 ppm, despite the influent has enough organic matter and the Q_waste is very low.
• The effluent has a big value of COD (550 ppm) and, therefore, of Norg too (48 ppm)…..it is like if the effluent could not settle properly, despite I think that I have enough time for the settle phase….

Thanks in advance

Please send your case to mikebydhi@dhigroup.com: I will take a look.
And post an answer here, should it be relevant for other users.

The problem has been solved thanks to your indications. The key was a mistake in the previous calculations in order to estimate the values of the different parameters that define the SBR. The concrete mistake was in the Q_draw, smaller than the correct one. It is for that reason I had an undesirable effluent during other phases, avoiding the growth of MLSS and a bad quality in the effluent.

Thanks a lot for your kind and quick answer.