• Re: Nitrogen removal in SBR


    Following your indications, I modified and renamed the two files you mentioned in order to turn off (= 0) Q_Bypass during the reaction phase:

    • wwtp.base.SBR.sbrpointsettler1phasereact_ContinuousFeed
    • wwtp.base.SBR_ContinuousFeed

    I understood that the file named ”wwtp.base.SBR_ContinuousFeed” should be copied in the folder  named “MODEL” and the “wwtp.base.SBR.sbrpointsettler1phasereact_ContinuousFeed” file should be copied in the folder named (MODEL/SBR). Is it right? If it is, I do not know why, after doing that, when I open a West project and use a SBR block, it does not appear in “Properties/Genral/ClassName” the possibility to select the “SBR.sbrpointsettler1phasereact_ContinuousFeed”.
    I would appreciate your indications to solve this problem if it is possible.

    Thank you very much.
  • How to simulate an UASB


    We would like to ask you about a usual process used in industrial facilities like is the UASB, a realistic option when the influent presents huge amounts
    of COD. We have used the “anaerobic digester block” in other occasions to treat the decanted sludge, but we have the doubt about if it could be considered correctly to use the same block (anaerobic digestor) directly in the waterline to simulate an UASB.

    Thank you for your time.
  • Sand Filters

    I would like to ask a few questions about the Sand Filter block.

    • I have the impression that the “Filtration period” and “Backwash Period” cannot alternate automatically between each other…. Is it correct? I find the parameter “Backwash” where I must decide to input a “1” or a “0”, and all this leads me to think that. It is like the sand filter could not operate continuously….

    • About the “Q_Backwash”, how do I determinate its value in West (it is not a “parameter” that I can introduce) and how can I introduce that flow in the exact moment when the filter needs to be backwashed?

    • It is difficult to imagine how I could build a sand filter model of at least 2 lines working in parallel, considering the fact that when one of them is in “Backwash period”, the other one receives all the influent and I do not want to generate a value for the “Q_out_Unfiltered” varaible. In summary, I do not find the way to simulate continuously a sand filter….

    Thanks a lot for your time. 
  • Re: Nitrogen removal in SBR

    You are absolutely right. I have found the different files that you have mentioned and have identified the lines to change.
    The only doubt that now arises is, in case of having WESTforDESIGN, is it possible to create this variation of the SBR model and conserve at the same time the original SBR model? I am not sure if with WESTforDESIGN allows creating new blocks…..

    Thanks for your time.
  • Nitrogen removal in SBR

    How I can properly modeling a SBR reactor if I desire to remove nitrogen through different phases (anoxic-oxic,…)?

    The difficulty that I find in that situation is that the “fill phase” is the only moment when the water enters to the tank, so, with that premise, a for example 7 reaction phases submodel where I can alternate anoxi-oxic-anoxic…. phases, it is not possible to add raw water to the tank during that “Reaction phase” and therefore my system is something like a N-D system (if we supposed that we introduce oxygen during the fill phase) instead a D-N system, which should be the right way to eliminate Nitrogen.

    In brief, my problem is that I cannot add raw water to the SBR during the alternation of the different “reaction phases”.  How have you solved this “inconvenient” ? Maybe I am wrong in something?

    Thanks a lot for your time

  • Re: SBR & Desynchronization

    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.
  • Re: SBR & Desynchronization

    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
  • SBR & Desynchronization


    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.