Fig. 1 illustrates the principle of using MFC for wastewater treatment. An MFC typically contains two electrodes (anode and
cathode). Bacteria on the anode decompose organic matter in wastewater producing electrons and protons. The electrons flow to the cathode through an external circuit, generating electricity, and protons diffuse from the anode to the cathode. Once at the cathode, the electrons and protons react with an electron acceptor, such as oxygen, and form water (Fig. 1).