Most suitable type of diffuser for SBR

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Hello, dear fellows!

I'm working in the design of an rectangular-shaped SBR for the treatment of psychiatric hospital wastewaters. What type of diffuser (tubular, disc...) could be more suitable for the system, regarding the following aspects:

-2 tanks

-Average flow = 81,6 m3/d

-total V = ~ 51 m3/tank, 4 cycles per day per tank

-Fill volume = 10,2 m3/fill

-Calculated required O2 per tank: 2,36 kg O2/h per tank

-dimensions (h x L x w) = 4 m x 7 m x 2 m

-BOD, COD, TSS, TN, TP (as chosen design parameters) = 285, 507, 95, 25,4 and 5,5 mg/L respectively

-BOD, COD, TSS, TN TP (expected at the effluent): 20, 50, 20, 1, 1 mg/L respectively

Nitrification and denitrification processes are expected to be achieved.

 

Thank you very much.

 

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6 Answers

  1. Hello Michael, we use Std. 7" Sanitaires for this kind of application.
    Aerostrips are, also a good option, in my opinion: easy to install they have better SOTE than other systems (even though they require PAA injection...) . You may want to get in touch with Tom Frenkel of Stamford Scientific, a true expert in this field.
     

  2. We are another SBR supplier and I would like to add a couple of other points.  Both tubes and discs will work for SBRs.  To minimize maintenance, we use retrievable diffusers where possible and fixed floor mounted diffusers where it is not.  The other consideration is the amount of mixing energy that you will need for this particular application.  Depending on the mixing, you may want to consider one type or another.

  3. In our experience diffusers with silicone membranes last longer and maintain their high performance. That's why we apply them in our SBR systems, even in round tanks.

    The tube diffusers from OTT (Germany) have several length options and can be easily adapted to most tank sizes. 

    And I agree with Michael Martin, deeper tanks give higher efficiency with a denser bottom coverage by the diffusers.

  5. @ 'We have a 6 MGD plant with 4 reactors and use Sanitaire discs. 2,600 discs in each 1.5 MG reactor. We have had others that were cheaper but they became clogged. These are the best for SBR's because they delivery lots of air quickly when you need it during react. There life span is about 8 years for maximum delivery. Our plant is about 13 years old'

    1 Comment

    1. Thank you. I'll look for this brand, I need to find some of the constants required for the design of aeration equipment (diffusers), but haven't found them for other brands in their data sheets.

  6. Hello, according to your info, you can install many types of diffusers. The choice would be more on the diffusers quality and installation type/duration and so on than only geometry.

    As I presume the technology is fine bubbles diffusers, you should try to have the max depth as possible (more than 4 meters would be great) to ensure better oxygen transfer efficiency and then make energy savings during the plant O&M.