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REMOVAL OF copper sulphate AND ZINC sulphate FROM WASTE WATER

HELLO,

WE ARE PICKLING COPPER AND BRASS SHEETS AND RINSING THEM WITH WATER AFTER PICKLING.

THIS WASTE WATER HAS copper sulphate AND ZINC sulphate WITH TRACES OF FREE SULFURIC ACID, IS THERE A PROCEDURE TO SEPARATE THE copper sulphate and ZINC sulphate FROM THE WATER.

THE PH OF THE WASTE WATER IS 4.

COMMENTS AND ADVICE REQUIRED.

THANKS IS ADVANCE

PETER MARKUS
- SINGAPORE
2005

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Do you just want to remove the copper and zinc or do you actually want to remove the copper and zinc as sulphate compounds? The approach will differ significantly.

A nanofiltration system (using divalent ion separation capable membranes)will retain a high degree of the copper and zinc as sulphate compounds. If you are looking to remove them to WHO or Singapore standards, you would probably need to use multiple passes to achieve compliant levels of the metals. However, the free acid ions will pass readily through the membrane, so expect a low pH in the permeate of the system.

If you are looking to simply remove the metals as ionic copper and zinc, you would see a high degree of removal to the low ppm or ppb range with an ion exchange system utilizing a chelating resin, which is specific for heavy metals. Little pH adjustment would be necessary to the influent of such a system under this scenario, however care should be taken to allow for pH adjustment as necessary in case there is a slug of more concentrated solution gets intot he rinse system.

Lastly, and alternate to this would be to completely recycle the water in a packed bed ion exchnage system, where you would get 99%+ of the water back in the form of DI water, and be left with an enriched solution of copper and zinc (either in chloride or sulphate counter ions) in the regenerant, plus an alkaline sodium sulphate/sodium hydroxide waste originating from the anion column. Depending on the incoming TDS of the water, this could be an excellent approach for you to consider.

Tom Baker
wastewater treatment specialist - Warminster, Pennsylvania
2005

See the other responses for an inquiry from India.

Juzer Jangbarwala
- Brea, California
2005