Hello!

I was hoping someone could help me with what to try in the laboratory to reduce COD levels in a crystaline sorbitol waste stream.

There is a 5000 gal holding tank for the waste water of this process.  The COD can range from 10,000 to 150,000+.  Once analyzed it is then released (sometimes partially depending on COD levels) into a main wastewater system that discharges approximately 80,000 gpd.

We are trying to determine if we could feed something into this tank to knock out the COD before being discharged.  I have tried peroxide and am not getting good results.  I am not sure what percentage should be added but have tried ranges of 0.2% - 8.0% of 50% H2O2.  I have also tried removing the residual peroxide with pH, heat, and catalase before running the COD due to false high values when residual peroxide is present.

Any ideas that I could try in the lab would be greatly appreciated!

Thank you!

C6H14O6 - based on the chemical structure and the numerous OH molecules - I would think that oxidation via peroxide would not work. You'd first have to go through a redox stage - to break the OH off then oxidize to reduce the C-H bonds, and repeat. Lab experiments in the past we used electrolytic oxidation followed by UV, then back to electrolytic oxidation, then uV etc in a continous batch cycle. That worked.
Other depending on what the charachteristics of the wastewater are (dissolved metals andminerals) -is to oxidize to get the metals into a insoluble precipitate - filter; dose with alum or cerium to flocculate the phosphates - filter, then run the remaining through nanofiltration to concentrate the sorbital - which should be re-useable -and disharge the water to he Muni WWTP.