Energy Production in Microbial Desalination Cells and Its Effects on Desalinatio

Abstract

Microbial desalination cell (MDC) is a newly developed technology for energy-efficient saltwater desalination and wastewater treatment. It has been observed that energy production and maximizing desalination efficiency may have a contradictory relationship. To further understand the interaction between energy production and desalination efficiency, herein we have investigated energy production and desalination efficiency in aMDC affected by salt concentrations/composition (5-20 g/L NaCl and actual seawater) and external resistances (10k to 0.1 &!).Themaximum energy production with respect to total desalinated water was 0.234, 0.3113, 0.3660 and 0.4113 kWh/m3(desalinated water) operated with 5 g/L, 10 g/L, 20 g/L NaCl, and real seawater, respectively.The highest energy produced with respect to kg COD removal was0.1059, 0.1194, 0.1164 and 0.2245 kWh/kg COD operated with 5 g/ L, 10 g/L, 20 g/L NaCl, and real seawater, respectively.As expected, COD removal and the desalination performance were all directly influenced by the external resistance. Significantly, higher COD removal was obtained when UMDCs operated under higher external resistance (100-1000 W), and higher desalination performance obtained under lower external resistance (0.1 to 1 W).These results demonstrated the linkage between energy production, desalination and COD removal in UMDC.