Application of electrochemical process for landfill leachate treatment with emphasis on heavy metal and organic removal

This study was conducted to investigate the mechanisms of electrochemical treatment of a landfill leachate with emphasis on lead and organic removal. Laboratory electrochemical experiments were conducted using both synthetic wastewater and landfill leachate samples. From the synthetic wastewater experiments, the lead removal efficiencies were found to be more than 99%. The lead removal was observed to be dependent on: the electrical current, ratio between reacting surface area and volume of reactor and operation time, and following a first-order reaction. Similar results on lead removal were obtained when the landfill leachate samples were treated in the electrochemical reactor; the percent removal of soluble biological oxygen demand and soluble chemical oxygen demand concentrations from the landfill leachate during the electrochemical treatment were 30-60%, while the color removal was 70%. The sludge generated from the electrochemical reactions using the synthetic lead wastewater, analyzed by X-ray diffractometry, was found to be composed mainly of maghemite, magnetite, and laurionite. Based on the X-ray fluorescence spectrometry analysis, the percent contents of iron and lead were 68.6% as maghemite and 10.1% as lead oxide, respectively. The sludge generated from the landfill leachate treatment containing lead, analyzed by X-ray diffractometry, was found to be composed mainly of maghemite. Based on the X-ray fluorescence spectrometry analysis, the percent contents of iron and lead in the sludge were 69.49% as maghemite and 0.63% as lead oxide, respectively. The sludge volume index, capillary suction time and leachability values of the sludge were in suitable range for settling, dewatering and disposal.