Because of the high concentration of heavy metals in the sediment sludge produced from industrial wastewater treatment, direct disposal of this sludge in landfill sites will cause serious soil and groundwater pollution. Traditionally, the industrial sludge in Taiwan is first solidified and the products need to pass through the toxicity characteristic leaching procedure (TCLP) test prior to disposal on landfill. However, the increasing of sludge volume after a solidification process will shorten the lifetime of a landfill, especially in the land-limited Taiwan. The objective of this study is to develop a microwave process, which can reduce the volume and the leaching of heavy metals from the sludge and effectively mineralize the industrial sludge.