engleski

Characterization of Electroplating Sludge Prior/After CaO Based Solidification/Stabilization

Eighteen samples of electroplating sludge were taken from three vertical profiles of waste storage pond of zinc plating facility. Dry matter and organic matter content, pH value, bulk concentrations and leachates composition were determined. Composite sample of the sludge was treated with calcium oxide (10% to 70%) and the obtained solidificate was tested again. Significant variations of all measured parameters were obtained among the profiles of untreated waste. Dry matter content varied from 12.5% to 45.5%, organic matter from 9.43 to 29.39 % and pH value from 3.42 to 5.90 (mean value = 4.34). Iron content ranging form 3.84% to 19.14 % (mean value = 13.6%), and zinc from 1.09 % to 5.82 % (mean value = 3.34 %). According to its bulk composition, this material was not suitable for feasible recovery of iron and zinc. According to its leachate composition, this material was categorized as hazardous waste and requires pretreatment before landfilling or reuse. Addition of 50 % of CaO into the sludge reduced zinc concentration 79 times and nickel concentration 45 times in DIN38414-S4 leachate of solidified waste compared to original sludge converting hazardous waste into inert material suitable for landfilling or reuse in construction.

zinc; electroplating sludge; solidification/stabilization; leaching

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