Removing Organic Colourants from Wastewater

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Which method for removing organic colourants from wastewater has the best efficiency/cost ratio? 

Which methods have you used and how happy are you with the results? 

The wastewater will be released into the environment.

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10 Answers

  1. Consider Submerged Arc (SA) depollution technology for removing organic colorants from wastewater. The SA uses a high-current low-voltage electrical discharge between electrodes in the wastewater to generate plasma bubbles within the water. This plasma produces ultra-violet (UV) radiation and short-lived radical oxidants. The radical oxidants, primarily hydroxyl (OH·) and its byproducts, oxidize organic molecules including pollutants and the cell walls of bacteria. UV damages the DNA of bacteria and viruses. The effectiveness of the method may be seen by its extremely high yield in treating treatment 100 mg/l methylene blue (MB) solution: ~500 g/kWh @ 95% removal. Most important, the cost is low (e.g.

  2. Consider Submerged Arc (SA) depollution technology for removing organic colorants from wastewater. The SA uses a high-current low-voltage electrical discharge between electrodes in the wastewater to generate plasma bubbles within the water. This plasma produces ultra-violet (UV) radiation and short-lived radical oxidants. The radical oxidants, primarily hydroxyl (OH•) and its byproducts, oxidize organic molecules including pollutants and the cell walls of bacteria. UV damages the DNA of bacteria and viruses. The effectiveness of the method may be seen by its extremely high yield in treating treatment 100 mg/l methylene blue (MB) solution: ~500 g/kWh @ 95% removal. Most important, the cost is low (e.g.

  3. I agree with Mr.Boyter: "answer ​depends on the ​level of color, ​types of ​colorants...". But with Vacuum Evaporators, we already treat a lot of different kind of waste water with dyes and pigments. If you send us a sample, we can test it in our laboratory in Italy.

    Electrical consumption vary from 100-130 Wh/liter to 10-20 Wh/liter in case you have hot fluid in your factory (for example steam, hot water, exhaust gas, etc....). Send us (p.cesana@schell-international.com) more details regarding your wastewater, in order to design a proper machine maybe similar to the one shown in this link: colourants contamined effluent treat to save water reused for production.

    https://www.linkedin.com/feed/update/urn:li:activity:6329915113059028992

  4. Hello Peter, we are having promising results from a combination of biological anaerobic and aerobic processes. As pointed out by Henry Boyter, any better answer could be strictly related  the ​level of color, ​types of ​colorants, and ​the effluent ​permit ​requirements.
    Merry Christmas.
     

  5.  I have had success with removing colour in effluent waters with electrocoagulation. One instance was the removal of dyes from  tannery waste, the other was blood in water at a abattoir. Easy to install and run  

  6. Coloured wastewater is extremely variable in composition due to the amount of dyes or chemicals used in processing and most of these compounds have a complex structure which is resilient to light, biological or UV treatments. Arvia’s Nyex treatment systems preferentially remove persistent colour using a combination of adsorption and oxidation within a single unit.

  7. Advanced oxidation process is best but it is very much costly...!!! Other ways include use of UF,NF,RO membranes but as said in other answers level of color and other parameters are more needed to give a perfect answer

  8. I do agree that the treatment regime for treating the color matters that present in wastewater is based on the extent of organic matters that present in wastewater, several treatments could be used such Coagulation, Oxidation, Adsorption, ..... the choice of treatment is based on the level of coloring caused organic matters in water, influent flow, ..

    For low level of colored organic matters, you can go through Activated Carbon Filtration.

  9. Unfortunately, the answer depends on the level of color, types of colorants, and the effluent permit requirements. Even with textile colorants, there are several answers depending on the chemical family of the dyes and/or pigments.

    The usual systems to test are oxidants (ozone, peroxide), coagulation, anoxic treatment, carbon, and filtration (low MWCO UF, NF, RO). Usually, that is the order when considering cost. Chlorine was the best for many years, but chlorine is basically not allowed in most locations.

    For diverse and large systems, you may require a combination. Some textile facilities use anoxic, ozone, and coagulation to meet very strict permit limits.

     

    If you have more data, you could get better answers.

  10. Powdered activated carbon is the best and cheapest solution, according to my experience.

    1 Comment

    1. As was mentioned before, oxidation and coagulation are the most efficient methods for color WW purification. If you want a cost effective process  I would recommend the continuous Electro Fenton process which gives it all in one process and it is very flexible with concentrations as you can easily play with the currents and flow rate.