Dairy Effluent Treatment Plant (ETP)

We have etp plant having capacity 1200 Kl per day, but never run at it's high capacity. Whenever we try to increase the flow rate of inlet water sludge starts to float on clarifier which takes several days to recover though we have one ANAEROBIC BIOLOGICAL PROCESS ( UASBR  PROCESS) also.

Taxonomy

• Anaerobic Digestion
• Effluent
• Sludge Separation
• Sludge Treatment
• Sludge Management
• Biological Treatment
• Sludge Treatment & Management
• Dairy
• Clarifier
• Lamella clarifier
• waste activated sludge
• Biological Wastewater Treatment Market

10 Answers

1. Hi Arun,
   
   As you are increasing the flow, then the equilibrium inside the UASB is distrubed and you can be increasing the bacteria concentration on the effluent. Then the anaerobic process can continue in the clarifier and you can have some methane in that step.
   
   Of course we could need more data than the posted. But we could think explore the follwing options:
   
   1) You could increase the equalization tank to don't distrube the operation flow all day long.
   2) You could integrate an aerobic step before the clarifier.
   
   
   Regards,
    

2. Do you utilise any pre-screens to reduce the amount of sludge entering the clarifier?

   One or two stage screening beforehand can work wonders.

3. In my oppinion UASB process to treat dairy effluents are not recomended. It is better to use aerobic processes. Aniway you have to evaluate how your primary processes are running. To see how your system is working I would indicate to do a test to calculate gas production. Good luck 

4. Sounds like you have too high an upflow velocity in the clarifier, check your diameter of tank required against the recorded inflow and upflow velocity, I suggest you utilise an upflow of 0.5 to 1.0 m/hr to determine your hydraulic loading rate.

   Additionally, are you withdrawing your settled sludge adeqautely? If this accumulates it can affect the separation process your are attempting across the clarifier.

   You may have filamentous bacteria that have manifested in your upstream process, this can also lead to ineffective settling and subsequent solids carryover.

   Have you any water analysis to share? gary@dikubu.co.za

   Regards

    

5. What is the End use of treated water ? Let me know to offer you solution .

6. Have you checked the operating parameters of the clarifier? Maybe the upward velocity is to high or the recycle ratio requires adjustment when you increase the flow. I would check this before you look at biological factors.

7. Hi Arun, the comments below are very valid. Just one other consideration. As you increase the flow you will change the F/M ratio (food to microorganism ratio).  Initially this will result in a high food to microorganism ration resulting in rapid growth of your biomass, but poorer floc formation.  It should stabilise after a few days, but you may need to change your sludge wastage settings in order to achieve an acceptable sludge age.  

8. ¿Do you have a DAF or similar process at the beginning of the WWTP?... Fats and oils tend to attach (to cover) to the biological flocs (either they are aerobic or anaerobic) and affect the process 

9. Dairy Effluent Treatment Plant (ETP)

   It's an emulsion problem in milk wastewater, where water and fat never mix. However, this problem can be solved by using a certain formula, where each bond can be treated simultaneously. if this waste is only cleaned to be disposed of it is very easy, but if it is to be used again as clean water, of course it requires a finishing touch. 
   So, if you like, we can work it out together. 
   Thank you

10. You will want to collect some of the floating material and look at it under a microscope. Great chances you are forming filmentous bacteria. This will be very obvious under a microscope.  Another condition is when you are forming N2 and the gas bubbles get trapped on sludge particles.  The moment there is increased flow the particles separate and the gas bubbles float the solids.