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Textile Effluent Treatment:Troubleshooting

A treatment plant of textile effluent; with sequence of operation = primary treatment (lime+FeSO4) - Unaerobic treatment - Aerobic treatment - Secondary clarifier - Tertiary treatment.  We have a problem that when we start flow from unaerobic to aerobic treatment, it becomes black instantly. What could be the reason and solution?

Santosh Shiragave




The use of anaerobic system before aerobic would generally mean a very high C.O.D. The change to dark; blackish colour would mean the death of the micro organisms. This could be due to so many factors, such as the organisms may not be surviving in aerobic conditions, or an excess of the Micro organisms could lead to putrefaction. If there is proper retention in the equalisation tank, I would suggest use of bioaugmentation there and maybe even shut down anaerobic treatment altogether.

You may visit

Keshav Agarwal


Go to Tirupur and see how they do it. They have an operating plant there since 2005.


Box 4981
Oak Brook, IL 60522-4981


Dear Mr.Shiragave,

Your question on the above problem to indiawaterportal has been diverted to me for a reply.I am a water management consultant with 40 years experience in the field.

I am unable to give you any solutions due to the sheer lack of information.
1.What is the analysis of effluent at the inlet to the plant and what is the colour?
2.What is the treatment flow rate in m3/hr and what is the temperature?
3.What is the volume of your effluent balancing tank?
4.What is the BOD & COD at the outlet of the anaerobic section,outlet of aerobic section and after tertiary treatment(if you have one)?
5.Is yours a batch process or a continuous one?
6.If your effluent turns black when flow from anaerobic to aerobic,what is the final effluent colour at the end of all the treatment?

I hope you can give me all this information as I can not even analyse the problem till I get all this information.


Water Management Consultant


THis problem could be arises due to the one of the following reasons:

1.Carryover of ferrous sulphate from primary clarifier to aeriation tank/aerobic reatment system

2.In sufficient oxygen supply/demand

3. COD of inlet to the aerobic system is more than 1000mg/lt

4. pH is not maintaing in the range 6.5 to 9.0

I am maintaining an effluent treatment plant of 2000kl per day with 1000 kl per day recovered water. The unit comprises the biological treatment---------physiological treatment-------tertiary treatment and followed by nano filteration and reverse osmosis system

Arun Pandey


basically the reason of effluent black is due to high COD& tubidity levels,its ph is also less than 5 so it completly turn in to septic to avoid this condition you can use PVC film media either in anaerobic,or aerobic tank.along with that you can use Culture called EFFECTIVE MICROORGANISM which reduce the blackish colour of water up to 80-855 if you are using organic dye..Or 40-50% in case of inorganic dye. i hope your problem will be solved soon.


In case you have not yet found answer to your problem Please indicate the influent characteristics. In my opinion anaerobic treatment may not be necessary, as the coagulation-settling otherwise remove substantial colour, SS, BOD and COD.

I have been monitoring CETP at Pali & Balotra (in Rajasthan) treating textile processing waste over a decade. The process cosisting of "Equalization-Coagulation (Lime, Ferrous sulphate and Polyeletrolyte0-settling-extended aeration -setting" is giving satisfactory result i.e. within effluent discharge norms.

A.K.Seth Retired Scientist NEERI - Consultant

7. Effluent treatment plant performance

Dear Sir,

I am running textile effluent treatment plant having capacity of 3 mld ,our physio-chemical treatment works good we get 50% reduction and almost 90 % colour removal in primary treatment.

And we have the FAB fluidised aerobic treatment (attached growth) biological system , in this bio-reactor we maintain PH 7 to 8 and DO 1-3 but the reduction across the FAB is very less i.e.20% COD/BOD ratio is good,inlet parameters are as per design then also the outlet parameters are not matching pollution control board norms 

How do I increase the reduction in FAB upto 5?

8. Dear Mr. Ravindra

Dear Mr. Ravindra Jadhav,

You have not mentioned what physio-chemical treatment you are using?

I think the problem is the generation of toxic amines resulting in inhibition of microbial growth in your biological system. Furthermore the biodegradability as you have mentioned is very less to be treated in aerobic system.

Better optimize the physico-chemical treatment. Do not target maximum removal in physico-chemical system.

Feel free to call me. I can suggest you something novel and effective.


Bharat Lodha,

Researcher 1,

Battelle Science and Technology India Pvt. Ltd.

Ph: +91-9321950886

9. Solution for PVA containing high COD textile wastewater

Dear Sir,

We are conducting research on PVA degradation and we have done experiments on actual PVA containing Textile waste water and we have developed biodegrdation process with 95% COD and PVA removal ability. If attractive solution of this problem is available with us, what will be the Market potential?

I have some questions: How many textile industries have PVA effluent problem? What is the volume and ppm of PVA containing effluent generated from these industries? What are the norms for discharge and recycle for PVA in effluent? And, what is the acceptable cost of treatment for discharge and recycling.

Thank you,

Sandip Magdum.

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