Removal of heavy metals from sewage sludge with a combination of bioleaching and electrokinetic remediation technology

► A combination of bioleaching and electrokinetic remediation technology is performed. ► It proves to remove Cu and Zn from sewage sludge effectively. ► Content of Cu and Zn decreases to 63.4 and 33.3 mg kg− 1, respectively. ► Organic sulfide of Cu, carbonate bounded and organic sulfide of Zn change to soluble.