"This work introduces a microbial battery for recovery of energy from reservoirs of organic matter, such as wastewater. Microorganisms at an anode oxidize dissolved organic substances, releasing electrons to an external circuit, where power can be extracted. The electrons then enter a solid-state electrode that remains solid as electrons accumulate within it. The solid-state electrode is periodically removed from the battery, oxidized, and reinstalled for sustained power production. Molecular oxygen is not introduced into the battery, and ion-exchange membranes are avoided, enabling high efficiencies of energy recovery."