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Chrome Treatment affected by alkaline cleaners?

June 9, 2009

I will be start a Chrome process for aluminum and waste water treatment plant to reduce the chrome.

I will be have a continuous waste water treatment to reduce chrome. I will be receive two different waste solutions: Chrome Acid Rinses and Alkaline rinses. I will be separate the solution to reduce the chrome at pH 2.5 and then on other reaction tank mix with the alkaline rinse, coagulant, caustic until pH 8.8, I want to know if after the mix the surfactants coming in to the alkaline rinse can affect the chrome precipitation on the clarifier.

Regards

Chavez Arturo
employee - Chihuahua, Mexico

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First of two simultaneous responses -- June 13, 2009

Cleaners and surfactants are notorious for causing metal removal problems. They do not interfere with precipitation; they interfere with effective flocculation and clarification of the effluent.

I'd advise great care - if there is nothing else required in the cleaner rinses but pH adjustment, could you do that on a batch basis? Or, perhaps, mix it in with the other effluent after metals removal, and then pH adjust?

Dave Wichern
Consultant - The Bronx, New York

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Second of two simultaneous responses --

Maybe. Since you do not know what the surfactants, etc. are in the cleaners and do not know the effect of mixing all your cleaners (and what ever else is in the stream) with the reduced chrome containing effluent it is impossible to say. I would strongly suggest you do some jar tests.

Gene Packman
process supplier - Great Neck, New York
June 13, 2009

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June 15, 2009

Hi Chaves,

Cleaners are by nature a bad thing to put in a waste treatment. Everything they are designed to do fights precipitation and flocculation. Many are chelated to one degree or another, One thing you have going for you is it is just rinse water so the concentration of the cleaner can be controlled somewhat. I recommend doing some jar tests in the lab and seeing what the results are. Dose up your reduction water with cleaner and see what happens. This is not a sure thing though. The true test is to run your system and monitor frequently until you are confident it works.

Trent Kaufman
electroplater - Galva, Illinois

There is always a possibility that the surfactants and chelators in the alkaline cleaner may interfere with your floccing polymer. Try a jar test beforehand. If there is a conflict, you may need to locate a different cleaner or flocculent.

George Brackett III
- Maine
June 16, 2009