I have seen the photos you sent and it seems to me that the two Krofta type DAFs you are using are over loaded or more easily that the chemicals dosage is not efficient.
The elimination of the soluble organic substance is done in most cases biologically.
In your case with a COD of 3700 mg / l and probably with a water temperature above 35 ° C I recommend the anaerobic biological treatment.
A UASB plant, widely used in the paper mill, has no problems in reducing COD below 800 mg / l, has low management and maintenance costs, low sludge production and does not require nutrients.
The investment cost is high, but if biogas is recovered, the cost / benefit ratio is certainly attractive.
My comment is around monitoring. You may want to have a quick and safe method for measuring the COD to confirm final effluent COD and treatment optimization including nutrient optimization. Learn why many pulp mills now use the PeCOD COD Analyzer, a true green method providing results in 10 minutes. Visit www.mantech-inc.com or email me directly at rmenegotto@mantech-inc.com. WhatsApp +1 519 835 5252
For last reply I sharing my idea to you to us MBR. But lastweek I went paper which which be faced with the Problem of Effluent same like you. Ok firstly You need long HRT for Anaerobic at least 5- 15 days in Thailand we use Modified Cover lagoon with De-sludge pipe with Acid pond to increasing VFA higher.For UASB here is not work because it is to short HRT, only 12 hrs the efficiency is only 65%, I solved this task by design new MCL sizing 45,000m3 now under construction. And after treated by UASB you need settling pond then COD of the Effluent will be decrease quit much or you can dosing PAC, Alum with less of polymer to settle down all SS. And these will lead to increasing aearation to treat wastewater to reach std. Finally if you install MBR everything will be reach WW std and you can reuse water to the process line.
I totally agree with Mr. DAD, MBR may be a solution to treat this high concentration of COD, for me I think you can use physical and chimical treatement by coagulation and floculation and then use a biological treatement by MBR.
I have more than 40 years experience treating industrial wastewater and your problem is not an uncommon one but first things must come first, data on your mill and material source. Also way more data on the treatment system and what the COD is made up of.
if you care to share this with me I can try to suggest what a solution could be. You can email me at
I agree with the comment of Thomas Gertz to use a high rate UASB to convert most soluble COD to biogas and thereby producing more energy than consumed.
Removing soluble COD by filtration, floatation or settling is nonesense and using AOP's at such high COD would be terribly expensive.
The following paper is a good discussion on recalcitrant organic compounds which could be the source of your COD, P&P effluent is noted for this and are not biodegradable.
HI Mohammed, I suggest that you analyse for organic and inorganic TDS to determine the organic TDS which will be the source of your soluble COD. Once known you can size an Ozone generator to inject the theoretical stoichiometric amount of O3 to the desired excess (800mg/L?) COD.
The most COD in paper industrial wastewater is as TDS, for the biodegradability in bioreactor a continuously external nutrients are required, which bring the operating costs up.
We recommend our lamella clarifier TUBEdek® to reduce the TSS, and thus the COD. CAPEX and OPEX can be significantly be reduced. For further more details, look on: www.enexio.com and don’t hesitate to contact me: youssef.rannane@enexio.com
COD or some of it can be reduced by activated carbon. Depending upon flow rate or total GPD that can be expensive and may or may not reach the desired level goal. With some testing the application of EC (electrocoagulation) has been very successful.
Regarding from your request base on soluble COD 3000 ppm, I do not think so. You need only Biological , AS ,MBR which can treat we to reach std to discharge. But in my point of view this soluble COD is TDS. I need more information from you,
Regarding from your request base on soluble COD 3000 ppm, I do not think so. You need only Biological , AS ,MBR which can treat we to reach std to discharge. But in my point of view this soluble COD is TDS. I need more information from you,
Dear Mohammad, please do let us know in which stage of treatment process you are getting 3000ppm COD. BAsed on that we can suggest which type of process can be used.
Soluble COD in paper mill effluent can be treated by high rate anaerobic processes such as UASB which will yield biogas fuel. Effluents such as yours can usually be treated with a favorable financial return on investment. In other words, if you can invest capital it will pay for itself.
I suggest our AOP to re-purify any kind and flow of wastewater into potable effluent to reuse safely in your paper process with 95% recovery efficiency at least, zero emission to air-water-soil, and low operating costs between another advantages.
We are pioneers in wastewater recycling since 2003; we warrant lower than 500 ppm effluent as usual standard of our technology performance.