EDTA wsate treatment ??

[Jeffrop]

Lady and gentlemen,

If anyone have the experience to treat the EDTA waste by The thermal hydrolysis technology ?? We want to destroy completely the EDTA waste (about 4000 mgr/l) by The thermal hydrolysis, what is the optimal condition ? I will appreciate if someone can share with us this experience.

Thanks

 

[kenvlach]

Why do you want to destroy the EDTA?
Is it complexed with hazardous metal cations?

EDTA is most commonly destroyed using hypochlorite at pH 10.
Other methods (ozone, hydrogen peroxide + UV, anodic oxidation) are all slower, more complex and expensive.
I'm sure that heating would speed up all of these methods, and adding an oxidizer would lower the necessary T & P for thermal hydrolysis.

see pp. 247-254 in Handbook of Effluent Treatment and Recycling for the Metal Finishing Industry, 2nd Edn., L. Hartinger, Finishing Publications Ltd. and ASM International (1994).

http://www.asminternational.org/Tem...=Ecommerce/ProductDisplay.cfm&ProductID=10819

 

[Jeffrop]

Hi Kinvlach,

Tks for your feedback, our EDTA wastes is EDTA-Ni, it is very stable ! the pilot test was ran at difference conditions (pH, oxidation (H2O2) thermal hydrolyze (high T&P), the complex EDTA-Ni was not be destroy !

JeffR

 

[kenvlach]

I know that H₂O₂ doesn't work at ambient conditions, but hypochlorite does. I use an excess, don't measure, just dose according to ORP reading. Also, I have another chelator present, ammonia, so lots of foaming at first & can observe color change to plain green [can even overdose with hypo to get blackish NiO!].
Good luck.

 

[kenvlach]

Another oxidizer that works (& isn't mentioned in wastewater treatment books) is nitric acid. I use it in the form of spent passivation or plating stripping solution. Adding a little H₂O₂ rejuvenates some of the spent nitric (converts nitrate back to nitric).

 

[Jeffrop]

Thanks you Kenvlach for the recommandation ! I will try it

Regards