Abstract: Methods for treating wastewater containing one or more heavy metals are disclosed. The methods can include providing a fuel cell, the fuel cell including: an anode having a catalyst; a cathode electrically coupled to the anode; and an ion-exchange membrane disposed between the anode and the cathode. The methods may also include contacting a fuel to the anode to oxidize the fuel and contacting the wastewater to the cathode to reduce at least a portion of the heavy metals in the wastewater. The methods for treating wastewater may advantageously provide an efficient means for treating the wastewater while producing electricity. Systems for treating wastewater are also disclosed.