Complementary functions within microbial fuel cells: Energy production and desalination

Lacking of ions strength and the buffer capacity in real wastewater significantly limited the practical application of microbial fuel cells (MFCs). Here we show that energy recovery efficiency of domestic wastewater in the anode chamber could be improved in a microbial desalination cell (MDC) by integrating desalination function into an MFC reactor. In the MDC reactor, raw domestic wastewater or saline water containing 100 mM NaCl and 100 mM NaHCO ₃ were used as the anode substrate and salt water in the middle chamber, respectively. Using wastewater as the only substrate, the maximum power density of the MDC was 7.55 W/m ³, which was significantly higher than the power output from MFC with 2.74 W/m ³. Chemical characteristics of the anolyte showed that the desalination process helped stabilize the wastewater pH and increased its conductivity by three times. Besides, comparison of microbial communities in the anode chamber between MDC and MFC is underway.