MBR Design

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Does anyone know a practical XLS-sheet to design a reasonable domestic wastewater treatment plant, as an MBR system, for irrigation-reuse of treated water?

Design: flows (peak and daily), influent and effluent qualities (TS, BOD5, COD, TN, P) are supposed to be known.

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10 Answers

  1. Dear all,

    First I want to thank every one that has collaborated to answer the problem of the design of the MBR I introduced. Their contribution were really useful and fruitful.

    For future contact  I need the emails of Mr Robert Beres, Mr jeremy dudley and Mr Eduardo Casado Fernández.

    Regards 

  3. Hi,

    most of these files would be company property and not many would share it like that,

    Roughly you would have two steps:

    • the MBR biological part is working like an activated sludge, so you can just use the Metcalf and Eddy or ATV method (based on sludge age and sludge production).
    • Then you just need to add the hydraulic part containing the membranes. This one is flux based, which is depending on temperature and used MLSS.

    I hope this will help you to build it up.

    Best regards

  4. In Australia there are manufactures and distributers of what we call biological system septic systems. I'm sure that the manufactures would have worked out what size you need to the number of people in the household. A Google search may help. We had one called Bio-Septic at our house that was on a 1.6 Ha block when we lived in a rural area. Every drop of water that went through the house went onto the block and I was able to grow over 350 trees during one of the driest times in living memory of what became known as the millennium drought.

  5. Dear Mr. Khomsi

    1) First of all you need to know the legal requirements for the treated water in Morocco to be reused. Not all the uses have the same requirements in water. 

    2) I am going to dare proposing you an alternative to MBR if you are dealing with a population below 15.000 E.P. Use a phytodepuration system. The question regarding that system and the XLS spreadsheet, it is that due to its features that sheet is not yet developed, but its building and maintenance costs are a key factor for considering the alternative. I could help you get in touch with Prof. Jesús Fernández González (Universidad Politécnica de Madrid), that could help you with that.

    Regards to @ll

    1 Comment

  6. I am currently writing a spreadsheet in Excel (I love spreadsheets!) for designing a facultative lagoon, a complete effluent irrigation onto a woodlot (flow rate, tree spacing, parameter levels, SAR, population projections, flow projections, evaporation, trans evaporation, overlap percentages of the above ground sprinkler systems, number of trees, tree species, etc...) its gonna take me about 3 months to complete each but when I am done, the user will simply have to enter in known parameters on the front page and all the hidden pages will complete the complex calculations. I am sorry that I don't have an easy answer for you except that each engineer should develop their own spreadsheet as rules and regulations are different in different countries...even if you had mine you would still need to tweak it to suit your needs.

    1 Comment

  7. CapdetWorks is the fastest rapid design tool for you to use, download it for a trial and let me know, we have an Academic Program as well.

    3 Comments

    1. @Patrice GR Doherty-Bigara, do not underestimate the work required for a MBR model that includes the effect of the membrane system. If all you want is the process biochemistry you can implement that quickly; but adding the interactions with the membranes is rather more involved.

      Because of the need for accuracy you may find it difficult using an Excel spreadsheet without the addition of macros to provide support for solving the differential equations; the standard Excel spreadsheet makes an Euler solver the natural approach, and this is at best inefficient, at worst unstable, for solving the equations associated with activated sludge systems.

    3. Better really to write your own, excel or mathcad files !! we can see what have been assume, used etc..  a template that can be change, modify etc..  RE: for ​irrigation-​reuse!

  8. As previous answers, I know GPS-X and Biowin softwares but no excel spreadsheet (we have some within Suez but confidential). I would say that the MBR design is complex due to the different design parameters depending on the membrane supplier (filtration capacity and hydraulic limit, max MLSS in membrane boxes, RAS requirements, scouring aeration, etc). Also the design will depend on the raw water quality and the effluent quality to reach (C+N+DN, etc).

    Regards 

  9. No. But there is a software product to design effluent treatment plant ETPSOFT03. This covers other treatment methods such as ASP, MBBR, Trickling filter and so on. But MBR process can be included. You can have more information about this software product on www.worldenviro.com

  10. Spreadsheet-based MBR design software? No.

    'Conventional' software to support design of MBRs? Yes.

    Capable of predicting likely effluent quality? Somewhat.

    All the models of which I am aware require that you specify the retention of particulates by the membrane - none of them can predict that from first principles. Other particulate-associated components are then calculated assuming that the retention is pro-rata to that of particulates, and that all soluble material will pass through the membrane.

    I am not aware that any have any meaningful estimate of pathogen removal; that is relegated to out-of-simulation engineering expertise. If it was included it would again be that the user specifies a likely value for coli/viruses in the effluent.

    Now we come to the nasty part: flow handling.

    The simplest approach assumes that the membrane is always adequately sized and controlled for the flows; so flow limits do not come into the modelling output.

    Then there is jump where you specify membrane resistances, expected cake resistances, cleaning frequencies, and the model has various parameters for fouling. This will give you a better prediction of the likely fall-off in performance with time, and the limits to flow that can be expected through a membrane for a given pressure drop. But the models are still in their infancy, and should be treated cautiously, and you need to continue to use vendor information to support the output. Fouling is the Achilles heel of membrane systems, and can mean that you will be unable to accommodate the peak flow.

    Software products with membranes: as far as I know, all can support the'simple approach.' I haven't seen all the software products, so while I know that GPS-X and WEST support some aspects of the more detailed models, I cannot be sure that Biowin, SIMBA# and SUMO do not also support them. STOAT, which I develop, has an unreleased version that has the more detailed membrane model - I think we are approaching the time when I can make that model available if needed.

    2 Comments