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Is RH meter necessary for a treatment plant treating CR6+

Hello -

I am consulting for an company having its own Effluent treatment plant for treating hexavalent chromium. They are using sodium bisulphite, sulfuric acid and sodium hydroxide in the process. The system is automatic and they are using PH meters and RH meters. I understand the need for PH meter but why is a RH meter necessary in the plant? There is no misting in the plant! Looking forward to some insights!

Anand Narayan
NCS Associates - Coimbatore, Tamilnadu, INDIA
2003

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First of two simultaneous responses --

Sorry, I don't know what you mean by 'RH meter', that's not a phrase I am familiar with. But ORP meters are necessary to determine if the hexavalent chromium has been reduced to trivalent form.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

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Second of two simultaneous responses --

Maybe the "RH meters" are ORP [oxidation-reduction potential] meters. ORP meters/controllers are needed for automated treatment of hexavalent chromium.

Ken Vlach [deceased]
- Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
2003