MBBR in Anaerobic reactor

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Hi dear experts:

Is it possible to use MBBR in Anaerobic reactor in a A2O process to eliminate the return activated sludge (RAS)?

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3 Answers

  1. Dear Iman,

     

    If you use a well designed aerobic MBBR you will not need any RAS, and if you increase the HRT in this MBBR system, you will have small sludge quantities.

     

    On the other hand the anaerobic digester could help you to diggest the sludge yield, but initially I don't think that the MBBR could help you to hava a better cost-effective performance of your described system.

    Regards,

     

    Orlando D. Gutiérrez Coronado

    2 Comments

    1. Dear Iman,

       

      Theoretically the activated sludge in this A2O process is used to give an extra power to the exixting activated sludge to take the P.

       

      Now the media used in MBBR is used to attache the bacterial and give a high solids retention time (SRT), and as a consequence reduce the volume of the reactor providing benefits in terms of stability and cost-effectiveness. Then we can think that a wider range of pollutants can be removed due to the variety of the microrganism livin in the media.

       

      Then we can think that the process can have a better performance if you use an MBBR media, and maybe depending on your removal requirement, you could use less RAS, but defitiviely I dont recommend you complete eliminate the RAS because you will need the same bacterial cultures passing thru the varioius steps of the process.

      Better even if you use a pilot test to look for the best set point for your process.

       

      Regards,

       

      Orlando D. Gutiérrez Coronado

    2. Hi dear Orlando:

      Thanks because of your reply. But I want to use the mediums in anaerobic reactor in a A2O process to eliminate the RAS to anaerobic reactor. what is your opinion about this?

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  2. Agree with Jeremy. The Bio-P removal process is result of P accumulating acting differently under Anaerobic Conditions and Aerobic conditions. During Anaerobic conditions the storage Capacity of bacteria is increased due to P release and PHA/PHB storage in the cell body. And during subsequent Aerobic step , the same bacteria takes up the P once again releasing the PHA/PHB or food they have stored in their cell structure. Thus, fixing them on media certainly will not help and thus elimination of RAS is also not feasible. However, you can add Media in the anoxic zone to reduce its foot print but provided you have rbCOD addition as methanol or ethanol or else the benefits are not much encouraging due to not able to maintain right redox potential .    

  3. The RAS is how the bacteria sequence between anaerobic/aerobic, which is the current understanding of the bioP system. If you avoid the RAS then you will not trigger P removal and lose treatment capacity. You may, of course, find that current understanding needs extending if your MBBR does work, but that might best be done as pilot-scale research.