Treating Formaldehyde Wastewater from Industrial Wastewater?

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I am having trouble designing a wastewater treatment plant which would treat wastewater contaminated with formaldehyde.

I would like to get some advice from someone who has experience in this area.

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16 Answers

  1. Depending on the initial data, the removal of formaldehyde can be effective using the oxidation-sorption method.

  2. We have a good experience with an aerobic biological process  for and industrial effluent with 2.000 ppm of Formaldehyde.

  3. We can design biological processes, chemical additive and or electrochemical processes to treat wastewater containing formaldehyde.  Their will be many parameters that will impact on what process will provide best economics for each project.

    Some good free advise would be to obtain a competent feasibility study by an independent water treatment consultant.

  4. I agree with Erik Rumbaugh.  Formaldehyde is actually produced by selected bacteria in a bio-digester, and in general is not a problem in wastewater treatment works, except at exceptionally high concentrations.  Many chemical toilets use formaldehyde to inhibit bacterial growth within the toilet system.  However the contents are normally disposed of at wastewater treatment works where they can be bio-degraded.  The following is the conclusion from a report I have attached on a study undertaken in South Africa on formaldehyde use in sanitation:

    "The overall conclusion is that the use of formaldehyde in chemical toilets does not pose a
    problem to normal wastewater treatment facilities below a conservative estimate of say
    20 mg/litre, whether it is a septic tank, aerobic treatment or anaerobic treatment. Given the
    low concentration of formaldehyde in the chemicals used, the large dilution when added to
    the holding tanks, and the rapid biodegradation of formaldehyde in a wastewater
    environment, this is a value which is very unlikely to be reached, of which no examples could
    be found. Even in the unusual case of King Shaka airport, the levels of formaldehyde is at
    least about four orders of magnitude lower than the level suggested."

  5. Since the formaldehyde is present in waste water is a biocide carcinogenic poison, We need following information before we can start thinking of possible solution to resolve the issue. 

    • Concentration of the formaldehyde.
    • Concentration of the formaldehyde...Derivatives. 
    • Other organics possible.
    • BOD, 
    • COD,
    • TDS,
    • pH,
    • Temperature
    • Flow Rate,
    • Location ...
    • Temperature Etc...

  6. Our company developed a bioreactor treatment scheme for formaldehyde wastewater at an adhesives manufacturing plant in suburban Boston, Massachusetts. Key to the process was developing a consortia of bacteria that had an affinity for formaldehyde. We worked with a bacteriologist, Dr. Ned Barden PhD who was able to isolate and culture a bacteria he calls FormaldeBac. specific to the wastestream. This was added to a bioreactor that used a venturi aerator capable of adding requisite dissolved oxygen while stripping CO2 to maintain a neutral pH and using the kinetic energy of the discharge for mixing and equalization in a 3,000 gallon tank. A packing media was added to the tank in poly bags to allow formation of CFU on a high surface substrate media. Treatment was on a daily batch basis and had filter bags and an activated carbon canister for polishing to ensure permit compliance with a local MWRA discharge permit.

  7. Like the others, it would be useful to know the concentration of Formaldehyde COD indeed if the concentration are relatively low  Biological system should cope with it. If the waste water is industrial with high concentration of formaldehyde it can be pre-treated by Oxidation methods. We offer AOP for these situation where the effluent can be totally oxidises (including ammonia if present) or the effluent can be pretreated before the biological system. AOP stand alone or AOP + BIO can be solution. 

  8. The choice of method of industrial wastewater treatment from formaldehyde depends on the production, the volume of wastewater and, of course, the concentration of formaldehyde and other contaminations, pH, temperature .

  9. My first approach is - why is formaldehyde in the wastewaster and can the processes be changed upstream to eliminate this factor - always look at the cause first.

  10. I agree with Don Sharpe's answer, except to note that because formaldehyde is relatively polar, it has a very low Henry's constant, thus, it will not air strip out of the water as readily as it may seem due to it's low molecular weight.  

    If the concentration is low (say under a few mg/l), you can also consider advanced chemical oxidation, such as UV and hydrogen peroxide or ozone and hydrogen peroxide, and others.

  11. Formaldehyde looks as though it shouldn't be difficult in breaking down because it is an organic molecule.  However it is also a biocide, inhibiting bacterial growth and is also a chemical, which can have a detrimental effect on the protozoa.  On experiments tried on a plant where formaldehyde was used and needed to be removed, there was a difficulty in obtaining good growth and there appeared times when growth became inhibited.  When growth did occur, the floc was weak and easily disrupted, which meant that a conventional settlement tank wouldn't work well.  This site did not have water with other nutrients, so there was little opportunity to dilute the formaldehyde with other materials.

    Based on this, if I was to build a plant, I would want a high dilution, to prevent formaldehyde from becoming toxic to the biology.  You will have to feed the plant with a nitrogen source and if ammonia is present, it will be a problem because ammonia oxidising bacteria are inhibited by formaldehyde.  Almost certainly you will have to use membrane separation rather than settlement tanks and a method to clean the membranes because of the fine floc.

    The other difficulty is the stress response.  Despite there being the correct nutrients and oxygen, there may be difficulties in the floc being sticky due to the stress of the formaldehyde causing some bacteria to generate polysaccharides.  These would end up blinding membranes.  Formaldehyde may also inhibit phosphate absorption from the water and may be part of the cause of the generation of sticky polysaccharides.

    Whatever, the plant will need to use fine bubble aeration.  This is not only due to the better oxygen transfer but will prevent  formaldehyde from being driven off in the vapour.  So you will need to avoid such systems as jet mix aeration, or oxygen systems using a venturi.

    The pH will need to be maintained at pH 7.2-7.6, so lime dosing or caustic dosing may be needed with tight monitoring.  

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  12. Formaldehyde molecules are relatively small and well biologically treatable. But it helps if you can seed from an  existing WWTP with similar wastewater composition. Control of pH and temperature (!) are important. We have done two plants from natural resin industry with very high COD inlet (15 - 20.000 mg/l) and outlet below 100 mg/l COD. Sludge settling for final clarification can be a problem, with small flocs when the temperature is too high (> 30 ºC), but can be solved.

  13. You need to provide concentration in and needed concentration out. Volume per day is also important as is the type of wastewater (food, textile, steel,etc). Unless you have something unusual, biological treatment is really the standard way of doing it.

  14. I have not had a problem with formaldehyde degradation in multiple wastewater plants. Key is concentration - at normal industrial wastewater levels, formaldehyde is readily degradable by a number of organisms.