Organic Removal From Baker Yeast Manufacturing

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We are working on a zero liquid discharge unit, the plant manufacture baker yeast from sugarcane molasses.

Input BOD/COD are in the range of  30000/60000 mg/l.

After treatment of UASB, this gets reduced by 60-70%. A huge volume of sludge is generated during this process, which is later removed in a settler.

Is there any way to reduce this sludge production? 

We use the biological system for reduction of BOD/COD. Final treated effluent is having  BOD/COD level of 6000-14000 mg/l.

Which other good methods can be applied to reduce the level of BOD/COD? 

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26 Answers

  1. The anaerobic process needs to be combined with an aerobic process to reduce sludge volumes. I suggest either retrofitting an aeration tank into the existing treatment plant or a membrane bio-reactor. Using membranes will provide better separation efficiencies than a settling tank, especially in colder temperatures.

    Depending on the design and membrane selection, a membrane bio-reactor should provide final treated effluent with BOD

  3. Pre-screening before biological treatment to around 100-microns for removal of non-soluble BOD/COD, followed by secondary micro-screening for residual removal of non-soluble BOD/COD. More information available at www.baleen.com 

  4. prem is correct.    very perceptive.  you can have a dual aerobic anaerobic reactor.  and you can also have them in tandem.  anaerobic and the followed by combined for polishing.  

  5. Thakur Ji,

    We can help you further treat your effleunt after anaerobic digestion to meet discharge norms / recycle the treated water to achieve ZLD.

    We have distillery spent wash treatment based on Electro-Chemistry and we can treat this effluent without any chemicals to colourless odourless water as per CPCB standards.

    Your effluent match distillery spent wash to a greater extent other than high temperature at the time of generation. We have recently tested some samples of bio-methanated bakers yeast effluent from SAF YEAST Chinckpokli unit.

    You may please contact us on info@aeolusbioenergy.com for further details.

    Regards,

    Niraj Mithani

    Director

    Aeolus Sustainable Bio Energy Pvt Ltd

    Surat Gujarat

  6. If I were you, I will select several UASB in series. As a food process waste water, the BOD can be easily reduced to a very low level as indicated by Mr. Gerd Teunissen, via COD < 200 mg/L. UASB or other anaerobic process is very efficient and suitable to treat this concentrated highly biodegradable wastewater.

  7. Look into a BVF anaerobic reactor system from ADI Systems. If aerobic polishing is required, the BVF can often take the wasted sludge from the aerobic system and digest it further. It is a low cost, low sludge production system, with multiple installations on molasses applications.

  8. You can improve existing system by Enhanced treatment by polishing off the residual biodegradable oxygen demand from effluents of anaerobic reactors, or the biodegradation of recalcitrant wastewater pollutants, usually requires sequenced anaerobic and aerobic bacteria activities. However, the combined activity of both bacteria can also be obtained in a single reactor. with either pure or mixed cultures showed that anaerobes can tolerate oxygen to a certain extent. The oxygen toxicity to methanogens in anaerobic sludges quantified in batch experiments, as well as in anaerobic reactors. The results showed that methanogens have a high tolerance to oxygen. In practice, it was confirmed that dissolved oxygen does not constitute any detrimental effect on reactor treatment performance. This means that the coexistence of anaerobic and aerobic bacteria in one single reactor is feasible and increases the potentials of wastewater treatment.

  9. Dear Thakur 

    The UASB may be overloaded and the question is what is the organic load rate.

    To reduce the BOD you may consieder a second anaerobic digester and to increase the solids retention time (I did it in MSW A.D). 

    Polishing by an aerobic system is obviously required. Attached growth may reduce the aerobic sludge production

    Feel free to contact me.

    Ilan Katz

    ilankz@yahoo.com

    Answered on by

    1 Comment

    1. It is a good idea to go for a  second ​anaerobic ​digester.  Do you have experience on this ( please Share  if possible) any article , research paper is also welcome.

      1 Comment reply

      1. I was operating such a system in Arrow Ecology, Israel. Arrowbio-global.com

        I can check your vertical velocity and OLR as well as suggest a secondary reactor or different operational scheme, according to water analysis and operational parameters  

        please contact by Email: ilankz@yahoo.com

        Ilan

        Commented on by

  10. Hope you produce methane out of UASB

    This anaerobic processwill generate more sludge only.  70% reduction itself is a great reduction. 

    However there are possibilities if you maintain a two compartment system for CH4 production.

    Or, you can try treqting the algae  final effluent using algae. Am sure that will give pure reusable quality water with high DO.

    1 Comment

  11. Have you considered upstream chemical inputs substitution as this can have a major influence on sludge quality and quantity.

  13. A combination of UASB ,UAFF can significantly improve efficiency even with reduced reactor height,as per some study reports.

    The following link may b useful ref from IWA published material for sludge reduction strategies in WWTP with relatively high organics and COD,BOD.

    SEE THE LINK IN THE ABOVE POST

  15. Mr.Thakur ji,

    Its sounds gud that u are working on ZLD.but first i remind u, ZLD plants having their limitations bcz its very costly based on loads so better we try to minimised BOD/COD load but as you mention their final outlet Range is high bcz now UASB performance  is below level,it might be increased upto 90%.

    and for your sludge concer i suggest you plz go through centrifuge/decanter using poly electrolytes dose for better sludge dewatering.if any query plz feel free any time.

     

  16. thakur ji,  

     

    for sure, you need Biocleaner.  there are units reducing sludge in UP for a paper mill.   We have an office in Noida.  sludge and odor are gone.  easily.  

  17. DEAR SIR, we are in Brazil, in our country there is many industry of alcohol combustible , we use process by electrolysis, with Ti4O7 (composite) plates and rectifier with high effcience, if yoy want more details I can send for you. this water can be used like recycled water in same Industry by 3 process electrolysis... conductivity after was half and others characteristics you can see in picture...

    my email : nilson@aguabrazil.com.br  skype nilsongof   whatsapp +55-11-971609595

  18. References some of my experiences, from UASB reactor we through to Up flow Fixed bioremedetion media, and arrange the recycle sludge from 20-40% to anaerob equil pond. The afforded bod/cod degradation will in the 75-85% it's depend on the pH level control and no any poison or retarded microorganisms growth.  Some times reach to 90% removal of BOD/COD.

  19. UASB reactor removal of BOD & COD is reasonably good, as remarked, but should be improved to up to 80%. Sludge can be reduced by drying in drying beds after dewatering to 20% DM. Since this is a food industry, total digestibility should be good enough to reach final COD < 150 mg/l with aerobic treatment, but pH correction and N & P dosing are absolutely necessary.

  20. You can do a small scale study using multi-chamber anaerobic digester on untreated effluent itself and generate biogas and then on discharge from anaerobic digester ,use aerobic treatment/usab to get irrigation water. In Pilot test, observe the rate of digestion at different Ph levels and also  result of mixing a small quantity of cattle dung slurry.
     Oils/ grease is an inhibiting and thus undesirable factor.

  21. Use a centrifuge for dewatering the sludge

  22. Hello Mr.Thakur,

    i would suggest our nanobubble DOF( Dissolved ozone floatation system) . In a demo at a sugar plant in UP we could reduce organic loads at the equalisation stage ( water post anerobic process) by pretreatment from 3500 COD approx to 50/60percent and then because of breaking up of the complex chains their aerobic biological process seemed to be working more efficiently and able to reduce to around 80/90 percent the microbes found it easy to process..So could remove the odour / Colour and bring COD to discharge levels..Infact if given further treatment we could get it to reuse levels.What sets us apart is the generation of hydroxyl radicals which has oxidation potential almost double of ozone.At the same time very excellent ability of nanobubbles for oil separation Send me your details and maybe we could discuss and understand better.. My email ID is harish@acsipl.com

  23. Dear Shashikant,

    The scheme you need to follow post anaerobic digester which could further give you biogas production as you BOD/COD values are quite promising for post anaerobic digestion as we have experiencen in doing same in one distillery.

    Then you need to have aerobic treatment to bring down the BOD/COD up to discharge standards.

    For sludge that could be used as soil conditioner or if added NPK then can used as fertiliser.

  24. Hi Shashikant,

    We have actually implmented some systems for BOD/COD removal. Sometimes treating systems more upstream to help remove any oil (which leads to COD/BOD production). We have done this with implementing SiC membranes upstream to help reduce BOD/COD downstream..

    You can email me, rmitra@h2osystems.ca We can potentially help you. Where are you located?

    1 Comment

  25. As Dave has said, the first thing to check is whether the waste can be minimised at source, or the effluent can be beneficially reused. 

    If you have to treat it, 60-70% COD removal in the UASB stage is reasonably good. You can test to see whether the waste is amenable to further anaerobic digestion at lab scale and, if so, you might want to check the efficiency of mixing in the UASB or consider a separate post-digestion anaerobic stage. I guess you're already recovering the biogas and using it? The sludge yield is an inevitable byproduct - it is material that was not digested in the UASB either because of poor mixing/ inadequate retention time or it is simply not degradable under anaerobic conditions. Pre-hydrolysis or ultrasonication techniques might improve digestion slightly, but at a price.

    The UASB effluent can then pass to an aerobic process such as activated sludge to reduce BOD and other parameters to as low as needed. To meet zero liquid discharge requirements for recycling or reusing the water you may need to add additional filtration stages. 

    1 Comment

    1. After Biologicals  Nano, Reverse Osmosis, SWRO and MEE is already installed. Problem is Nano Can't handle such high load of  BOD/COD

      1 Comment reply

      1. OK, understood. So now we need to establish what form the carbon is in. First is it particulate and can it be removed by prefiltration before the nano? If so we may be able to help using our FilterClear system.

        If it is soluble then we need to check how biodegradable is the residual carbon? You could check the BOD:COD ratio and carry out a respirometry test to check. If it is biodegradable at a reasonable rate then it suggests that the biological treatment isn't working efficiently. If it is slowly degradable you could consider advanced oxidation  (using UV, ozone or peroxide but probably not chlorine due to effects on membranes).

        Happy to help further as needed!

  26. Hello Shashikant; it sounds with COD values like that a lot can be done about preventing loss from the processing plant. This will save them money also! Secondly an out of the box thought... this waste could be of value as animal feed if zero liquid discharge means you have to evaporate the liquid anyway why not concentrate the waste to a syrup and sell as animal food?
     

    1 Comment

    1. I recommend a settler as the first step as an easy way to reduce BOD into the USAB. If the USAB effluent is greater than 5000 mg/L BOD add a second USAB- follow with Activated sludge -- Thicken and dewater the sludges for disposal.