Treatment of copper chemical mechanical polishing (Cu-CMP) wastewaters by batch electrocoagulation was found effective in simultaneously removing the very fine metal oxide particles, copper ion and organic pollutants in the previous investigations. In the present work, the continuous electrocoagulation tests were performed to explore their treatment efficiencies and to identify the optimum operating conditions. Inherently, this electrocoagulation process, in either batch or continuous operating mode, generates a significant amount of sludge that needs to be properly disposed. In this study, the freeze/thaw conditioning of sludge obtained from this process was investigated in an aim to greatly reducing the sludge volume. Experimental tests were conducted to identify proper freeze/thaw operating conditions. Several fundamental aspects, such as the moisture bonding energy estimated using DSC test data, were examined to elucidate the conditioning results. (c) 2006 Published by Elsevier B.V.