Wastewater with High COD, BOD & NH3N

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Wastewater with High COD, BOD & NH3N

We are a printing company. Below is our process flow of wastewater treatment

Collection sump - Oil trap - red box (electrocoagulation) - filter press - slow sand filter - Sequencing batch reactor 

Currently we are facing treated wastewater with high COD (400-600mg/l), BOD (97mg/l) and ammoniacal nitrogen (44mg/l).

Our pH value in SBR tank is high too (8.3-8.6). Foaming happened during aeration. Before this, we have wasted all sludge from SBR tank and refill it with influent and solution with a microorganism.

Could it be the root cause of the problem? What can I do to solve the problem?
 

 

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19 Answers

  3. After controlling the pH to 7 - 7.5, we managed to reduce the pollutants in our effluent (BOD = 33, NH3N = 11 & COD = 191 - 230). 

    However, we couldn't further reduce the COD, our local standard limit is 200, we hope it can be reduced to around 100.

    Is there any solution to further reduce COD?

    The microorganism solution we purchased had no problem degrade COD to less than 100 before. 

    2 Comments

    2. most of what they call hard cod is actually a lot of phenols and polyphenols.    like coffee has a hard time.  or germicidal soaps.  what you need to try is chem5.  instead of buying microbes, you should  try a small bioreactor.  this way, you won't have to buy microbes again.  and it also eliminates sludge and lowers ammonia.  take a look at this one minute video. 

      https://www.youtube.com/watch?v=Al7UHDb6zoU

       

       

  4.   :you must identify your problem by

    must know the SOUR concentration if it's Low your plant in toxic shock if high the plant straggling under high concentration of NH3 and BOD and you must, in that case, do the soluble BOD and NH3 to confirm this issue...the solutions are decreasing wasting and RAS to the system 

  5. I cannot find anything on Biograde 31.  Who makes it?  Does it have a specification for what is in it?  Many microbial products are on the market that claim to reduce BOD, COD, TSS etc. but unless the microbes are appropriate for the types of organics in your process, they may be worthless.  You need to measure the mixed liquor suspended solids (MLSS) in your SBR to see if the bugs are growing (increasing MLSS).  If the bugs are not flocculating they may be washing out.  A pH increase must be indicating biodegradation of organic acids (the salt form, e.g. Na acetate) or nitrate reduction.  Have you tried reducing or eliminating the anoxic phase?

    2 Comments

    1. hi Richard, I have no idea who makes  this biodegrade 31.  but not all microbes grow will increase MLSS.  some sets do eliminate sludge and these keep the mlss low.   

    2. We have been using this biograde 31 all this time. Our previous data shows that it can efficiently decrease COD and BOD.

      We increased aeration cycle but didn't eliminate  anoxic phase as we need it for settling. 

      We are sending our wastewater sample to lab today. Let's see how's the result.

      Thanks for the info, it's really helpful.

  6. We are using biograde 31 microorganism solution which specifically chosen to reduce BOD, COD and TSS.

    We managed to bring down the pH to 7.0 using Sulphuric acid.  However the pH increased to 8.5 again in one night. We did not let any influent in, and only added microorganism solution.

    Our COD, BOD and NH3N value are still high.

    I really appreciate anyone who can tell us what's wrong with our SBR tank. It has been one month since the reseeding.

    4 Comments

    3. not to worrying...most good microbe mixes are self limiting.  if it just stays under 9, then its a good set.  if it spikes to 9.5 or 10, then you may want to use another set.  

    4. this is very common.  that's when the microbes grow a lot.  in their log phase.  the microbes you are using are alkalizing microbes.   thus the pH increases.  

  7. I hate to see the BOD test used for industrial wastewater because the microbes used for BOD testing are completely unacclimated to the organics present.  Obviously there is a lot of COD remaining.  What "micro-organism" was added?  May or may not be appropriate for reseeding.  The high COD remaining may well inhibit nitrifiers and prevent good ammonia removal.  An appropriate reseeding bacterial product to reduce organics followed by nitrifier product may help restore operation.  Foam may well be new biomass growth related.  How long ago did the reseeding occur?  You should probably change your SBR aeration/anoxic schedule to longer aeration until COD drops and nitrate starts to show up in effluent.

     

  8.  

    Hi,

    Great comments below.

    With your pH being around 8, its actually quite beneficial for you. pH correction is  not necessary. The highest rate for nitrification is achieved around pH 8.1. When nitrification begins to occur you get a reduction in pH as alkalinity is consumed.

    As Mike Dooley said below, during denitrification you get an increase in alkalinity 3.57g of alkalinity per gram nitrate. This might be occurring post aeration, in settlement stage (after ammonia has been broken down to nitrate). A good identification is small air bubbles in the water during settlement.

    As you have just reseeded your SBR, I presume you still have quite a young sludge age. Keep WAS to none or minimum and treatment should get better in time.

    Did you have this issue prior to reseeding?

     

  9. this is very easy to solve.

    you need the right microbes to help.  you can use a bioreactor that is suited for printing press waste water.   you can use a stable bioreactor that will continually break down phenolic waste water and treat down the ammonia.

     

    this is a printing press in Manila and its an open demo site.  

    https://www.youtube.com/watch?v=VFB2uUF8TS0

    the water is very clear.  

    it saves lots of money.

    guaranteed

     

     

     

     

     

     

     

  10. Foaming can be chemical surfactant causing  or possible  combination of low sludge age, high DO and low loading (BOD). If you have high DO your can add anti-foam untill the sludge age improves. Increase pH in SBR is possibly Denitrification of high Nitrate levels in influent which generates alkalinity. What is total N in influent. 

  11. Great advises below. Solutions are simple, just go for ELECTRO-OXIDATION after Electro-coagulation and settling. You will be happy for ever. 

    We are treating complex effluents from printing and printing plate manufacturing industry just with electro-coagulation and electro-oxidation only. 

     

    Contact us if you still find difficulties. 

  12. Thanks all for replying!!

    We have equalization tank with the size of 1200 x 2390 x 370 mm. The size of our SBR tank is 1828 x 2133 x1500 mm.

    The pH in our equalization tank is good which is around 7-7.5. But the value increases after wastewater enters the SBR tank. At first we thought it somehow mixed up with pollutants that's why we wasted our sludge in SBR tank. After the wasting we managed to bring the pH down to 7.5-7.7, but the value increased after 2 days.

    The foam is white stable billowing foam. 

    We don't use new chemical so I have ruled out the possibility of change in wastewater composition.

    What we are doing now is try to increase the retention time and usage of microorganism solution.

    I will keep you guys updated.

    Again, thanks all, I really appreciate your help.
     

  13. There's not much to work with here, but seems clear that the SBR is probably where the immediate problem is.

    You need to ensure that the F/M ratio, sludge age, MLSS, MLVSS, SVI numbers are healthy. 

    From what you said it appears you have recently re-seeded/restarted the SBR. Perhaps your biomass growth and sludge age are still not adequate after the reseed. This may explain the foaming and low removal rates, i.e. still acclimatizing. 

    Ammonia removal process (nitrification) would take even longer to establish. If you don't have much ammonia in the influent, then you may have a lot of organic nitrogen that is being broken down in the SBR forming ammonia. Ammonia is basic; so it could be the cause of high pH. 

    There are quite a number of things need to be looked at in order to find out the root cause. It is best to call in someone knowledgeable to troubleshoot your system on site. Good luck!

  14. Can you supply numbers for the water going into the SBR. Also, have you checked to see if there is the right balance of nutrients. What is the foam like?

    Quick answer - Adjust pH, keep under air longer, hold back some waste for seeding.

    Root cause - C:N:P not in balance, Food to mass ratio too high, Sludge age too young.

    Would agree with Zainul Shiekh below.

  15. pH of 7 - 7.2 will be perfect

    Biology has to adopt anywhow so part of new microorganisms will die ending up as foam, that's normal

    You need pH correction. Also just for chech - if you wastewater composition changed during last month with involving some toxic materials

  16. Could you confirm the Quality (BOD/COD and N) at the Inlet of SBR.  I thought that might be :

    1. Start up method or acclimatization is fail.

    2. Inproper Bacteria Solution for your waste

    If it possible, introduce some sludge to SBR from your waste sludge to fastened up the process.  Waste Sludge can work better than the liquid microorganism

  17. Hi Sin Tian,

    I have faced similar issues with textile waste as well. Foaming was generally observed during cooler temperatures and during night. The way I approached was:

    1. Built an equalization tank to avoid shock loads and high variance 

    2. Reduced the pH to almost neutral levels or just below  (6 to 6.5) by adding ferric chloride and polymers before aeration

    3. Recommissioned the aeration tank for the biomass to acclimatize with the process

    4. Maintain a DO level of around 1 to 1.5 mg/l

    5. Used coconut shell charcoal powder as defoamer in the initial stages and once the system was stabilized, coconut shell powder was not required.

    Your BOD levels are in the lower side, this may influence your MLSS in the system which will also impact return activated sludge. Can you provide your biological characteristics at each stage including TDS?

    Foaming can occur in nutrient limited state. Hence, it is essential to investigate the type of chemicals or surfactants that you are using and look at alternatives if the foaming continues.

     

    1 Comment

    1. Dear Zainul and Sin,

      I'm not sure what kind of electrocuagulation you are applying, I have 15 years working with AOP degrading all kind of wastewater to purified or just for irrigation without dosing any chemical for treatment; what I can ensure with electro AOP you are stopped in primary degradation.

  18. Bonjour je ne pourrais vous conseiller qu'une chose qui vous serait profitable: aller à l'origine de la production de ces eaux usées et éliminer le plus possible de pollution. je voie mal comment, dans un effluent d'eaux usées en putréfaction, vous pouvez réintroduire de la vie (micro organisme). Où sont les caractéristiques Biologiques de votre effluent?

    Hello I could advise you only one thing that would benefit you: go to the origin of the production of these sewage and eliminate as much as possible of pollution. I see poorly how, in a rotting sewage effluent, you can reintroduce life (micro organism). Where are the biological characteristics of your effluent?