Generally, Secondary Treatment of the Industrial Wastewater Treatment Plant i.e. Biological Treatment such as Activated Sludge Process, Sequential Batch Reactor, Upflow Anaerobic Sludge Blanket Reactor, etc. is used to remove Bio-chemical Oxygen Demand.

For, Chemical Oxygen Demand Removal, Primary Treatment of the Industrial Wastewater Treatment Plant i.e. Settling, Advanced Oxidation, Physio-chemical, etc. are used.

it depends on the initial COD , if it is very high : you can use at first coagulation and after you can applicate Anodic oxidation or you can use directly Anodic oxidation but you need more time.But,anway  it is difficult to achieve mineralization.

Thanks dear guys, So we can't use activated sludge for COD reduction?

Nadel, i think we can't use these nano particles in acidic waste water.

in our case, the waste water has high COD and extremely acidic (Sulfuric Acid) also in large scale (nearly 2000 kg/h)

Sameer, what do you mean by physio-chemical?

Helena, Sorry, It's Physico-chemical Treatment. I apologize for the same.

Physico-chemical treatment is the treatment process which remove the impurities by coagulation, and flocculation followed by sedimentation.

Considering the acidic wastewater, you can settle the suspended solids by raising the pH of wastewater to 10-11 pH followed by neutralization. This shall significantly reduce the COD of the wastewater.

If your water is acidic then first you should neutralise the water with some basis solution and after that further treatment can be done. BOD and COD are related to each other. Ofcourse ASTP is also used for COD reduction.

If your water is acidic then first you should neutralise the water with some basis solution and after that further treatment can be done. BOD and COD are related to each other. Ofcourse activated sludge Treatment process used for COD reduction also.

pH is no problem ; it should be neutralized anyway for discharge. After neutralization, three aspects should be checked:  Partition of the total COD (i) between soluble (450nM filtration) and particulate forms; (ii) between inert and biodegradable fractions - see different methods available, and (iii) COD fractionation to assess biodegradation characteristics of different fractions, preferably by respirometric techniques.; in this order, if possible.

Then you decide on the optimum approach for treatment. 

Thanks dear sameer.

Thanks dear preeti.

Thanks dear Derin,

Do you have any article or book about these 3 fraction of COD?

how can i measure biodegradation characteristics? and how this thing affect  on choosing the optimum approach?

I kindly refer to you to our book entitled

"Industrial Wastewater Treatment by Activated Sludge" by IWA Publishing, 2009.

Please also consult   our ( numerous) papers on OUR  ( oxygen uptake rate) measurements and modeling. 

Thanks dear derin for introducing these sources.

Dear Helena...If Sulphuric acid is high in effluent as you mentioned...first you should try to recover H2SO4...It is welll established method. ...If you will neutralize effluent then TDS will become further high....then biological treatment will not be possible...At acidic pH fenton treatment is suitable to reduce COD...

if ph is 5.5,bod 300mg/l,cod 5000 mg/l ss-100mg/l whether activated sludge process is okay to treat the water

Hello Helena Mirzabeigi

Recently, a series of new oxidation methods for wastewater purification called Advanced Oxidation Processes (AOP), have received an increased attention as tertiary treatments.

The use of O3 as a chemical oxidant has been suggested in the latest literature as a potential technique for COD removal.

Phytorid wetland Engineering Technology is used for removal of COD removal from waste water..