Issues in Coagulation Process

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I am currently working on a waste water treatment project involving biological pre-treatment of dissolved air systems.

The residual water is waste product of a coffee company, with pH of 4.5, fats and oils range are between 40 and 50 ppm and total suspended solids of approximately 350.

The presence of tannins is apparently causing a short circuit in the coagulation and the flocculation process. Which treatment method would you suggest for treating this waste water?  

 

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14 Answers

  1. Hi Oscar, my company has had experience with treating wastewater for agriculture and food production in Asia and Australia. I would suggest using a membrane bio-reactor if you want to avoid the coagulation process since the membranes will filter down to 0.1 microns. The bio-reactor will speed up the aerobic digestion process of your fats, oils and ss. 

    An alternative would be to change your existing dissolved air technologies with fine and ultrafine bubble technology, I have found that this sort of technology is efficient at flocculation of fats, oils and ss without the need for chemicals. This can be further enhanced with passing the effluent through a static mixer which provides further flocculation. The floc can then be filtered out with a media or membrane filter if needed or allowed to settle with a clarifier.

    If you would like to know more, please email me at andrew@waterandoilsolutions.com.au

  4. Coagulation component extracted from Moringa oleifera seed prepared using sodium chloride salt solution can have excellent turbidity removal,though best around optimum ph of 7.

    With higher levels of organic loading UASB reactors work better

  5. Oscar,

    Removal of Tannins, all be it not at the concentration you are probably experiencing, is accomplished by dosage of a strong oxidant, such as hydrogen peroxide or bleach, followed by an organic coagulant such as poly-DADMAC's or polyamines.

    What happens in this process is the oxidant oxidizes the dissolved tannins, transforming them into particulate matter known as pin floc. Once they have transformed into this form, the coagulant can bridge them together into significantly larger particles that are much easier to remove.

    Please don't hesitate to contact me with any further questions.

    Troy Davis

    1 Comment

  6. we have a set of microbes that can break down tannins and can also move the pH from 4.5 to 7 without the use of caustic.  this set can be coupled with a set that can breakdown FOG.  

    you will not need to waste sludge..so there is no sludge handling.

    and its very cheap.  its geared towards helping contractors lessen headaches and helps the contracting/engineering company to make more money.

     

     

     

     

    1 Comment

    1. Eros...i would like to learn more about the microbes...

  7. We have a process that removes oxygen from the air and infuses the nearly pure oxygen into the effluent sidestream with 800 mg/L of nanobubbles( 1 to 10 nanos).  The bubbles stay in solution until consumed.

  8. good morning to all ,
    First of all thank you very much for your cordial answers, specifically the solution that I am looking for is to coagulate, flocculate and reduce tannins in a residual coffee water.

    According to their experience and products, what possibilities I have at hand.

    thank you very much.

  9. I have some experience remediating grease trap wastewater sourced from grease interceptors at restaurants. The Fatty acids, Oil, and Grease (FOG) were decanted for use in biodiesel production leaving an effluent with pH 4.3, 2.5 - 5 gm/l Hexane Extractable Materials (HEM), and  total Chemical Oxygen Demand (tCOD) of 15 - 23 gm/l  (ave 20,000mg/l) and soluble COD of 15 gm/l. Using High Rate Anaerobic Digestion (HRAD) with Organic Loading Rates (OLR) of 8.53 total and 7.23 soluble kg COD /m^3/day we reduced tCOD by >91% at Hydraulic Retention Times (HRT) of

  10. I am an engineer working for www.phakee.com over 30 years which Professional in water & wastewater treatment, Air pollution &Gas treatment. As insufficient information on your post that I only suggestion by roughly as following.(Pre-treatment by DAF  and Post treatment by activated sludge)

    Basic treatment diagram as below

    InfluentàRaw wastewater tankàNeutralization tankàFlocculationàDissolved air floatation tankàActivated sludge by MBR.-à Effluent

    1. First of all, the batch wastewater from CIP process and CEP process during cleaning production line process. Both wastewater have to balance by mixing with the continuous wastewater, because it has to continuously control Q&Q of wastewater before entering to treatment system.

    2. Neutralization by adding coagulant aid herein is Ca(OH)2  to ​raise your  pH.7

    3. Flocculation by adding An-polymer 1-2 ppm.

    4. To Removal suspended solid, oil and grease by DAF. Recommend advance technology such as Micro bubble pump use to generating fine bubble which replace saturate pressure tank

    5. To Removal organic matter in term of BOD, COD by activated sludge with MBR. Technology. If the contaminate has low organic matter you can oxidizing by chemical to decompose it, High contaminate will not economical by chemical.

    Would you like to get more information? Please give me more information as following.

    1. Wastewater qualities and quantities of Influent and effluent

    2. Existing treatment process diagram or recent treatment process diagram.

  11. Hi Oscar,

    When you are in this lower pH range, you will have some coagulation issues.  I work for USP Technologies, where we are the largest supplier of oxidants in North America.  I would suggest using some hydrogen peroxide upstream to raise your ORP, and then use your coagulants.  Some are obviously going to work better than others, so you will need to jar test, but by raising the ORP, you should see better and faster coagulation enhancement.  I hope this helps.  Please give me a call if you have any questions.  We sell turn-key H2O2 systems, engineered for your specific application, if you have interest.  Best of luck!  Sean L. Roop - Industrial Business Development Manager, USP Technologies.  My mobile # is 239-989-3581.  Thanks!

    1 Comment

  12. Hello Oscar

    your request deserves several scientific corrections. Nowadays many consultants speak - biological - treatment. Currently, there is no so-called solution - biological treatment - because it does not exist. The word treatment must be add the solution like for example: medical treatment, psychological treatment, processing, etc.

    In mother NATURE employs a single function that does not appear on your detail: biodegradation. This function must also be attached to the tool that applies this function: the bacteria. In your case you should specify: treatment - biological treatment. But you can't because it lacks certain conditions: effluent - biological, biological - treatment tool - environment - organic - settings - biological- All this is completely missing from your application.

    In what may well be dissolved air treatment? This means absolutely nothing. This is not because we see an abatement of a parameter like for example air or oxygen there is a 'cure' any. This is just from a defect of the device design to preserve this setting - biological- That wastewater come from a company coffee or other businesses, the effluent must have a totally - biological characteristic. It must contain no presence of chemical molecule.

    There must be a very important presence of micro-organism. the tool of purification must be design - organic-. This tool should have a design that preserves - biological - parameters from midpoint to purify. In this post we see no trace of these mandatory elements. Coagulation and flocculation processes are just decoys. I do not see how a clotting would efficacy to purify, see I would say the opposite because in this case the material accumulates and loses its - biological-features.

    For flocculation there is in the imaginative the more subtle it is. All wastewater are footprints of filaments: hair, fabric, vegetable. These come together and form a net. I'm desperately looking for a trace of a any treatment at this level. same conclusion as for coagulation.

    The presence of tannin will affect on the problem of saturation. How much t - biological - feature of this effluent will it fade? In my configurations - biological - treatment I dilute the less - biological - waste water - biological - waste water with a very important water.

    1 Comment

    1. Marius

      Thank you very much for your clarifications

      In the concept of the present system, the water that comes out of the DAF by an anaerobic reactor will be treated. These waters in certain concentrations of tannins are high and we need to lower COD.

      If I use fats and oils higher than 20 mg / l, it is an inhibitor of microorganisms.

      However we have not found the right chemical solution to work with the DAF.

      Greetings.

      Oscar

  13. my suggestion is to separate as much as possible suspended solids before coagulation and flocculation proces then use calcium hydroxide to rise the ph to 9-9,5, alumium sulphate as coagulant and anionic polielecrtolite as flocculant.

    we have experieced succesfully this proces in a tannery that produce hides treated with tannins.

    regards

     

    Marco Vallero

  14. Hi Oscar, 

    We have a South African product developed specifically for cost effective separation of suspended solids from waste streams. We are able to break oil/water emulsions and with our team of highly qualified and experienced chemists and biologists, we have yet to come across a wastewater stream from which we could not separate all suspended solids.  

    Please email me - rob@selectra.co.za for more information. 

    I look forward to hearing from you.

    Kind regards

    Rob