Combined wastewater treatment and recovery of copper from ash leachate

Paper in proceeding, 2012

Ashes from incineration of municipal solid waste contain metals, such as copper and zinc, in high concentrations. The metals can be leached out from the ashes using acids and recovered by electrolysis. To lower the energy demand of the electrolysis step, we have investigated a bioelectrochemical system for combined wastewater treatment and copper recovery from simulated ash leachate. Bacteria at the anode oxidize wastewater organics and produce a current that flows through an external circuit to the cathode, where copper is reduced and recovered. We tested a bioelectrochemical system with carbon anode and titanium cathode. With a cathode potential poised at -0.3 V, the energy required for copper reduction was reduced from 1.46 kWh/kg Cu with an abiotic anode compared to 0.23 kWh/kg Cu with a biological anode oxidizing acetate. With a cathode potential of 0.1 V, electrical energy could be recovered from the system together with copper.