Microbial desalination cells for improved performance in wastewater treatment, electricity production, and desalination

The low conductivity and alkalinity in municipal wastewater significantly limit power production from microbial fuel cells (MFCs). This study integrated desalination with wastewater treatment and electricity production in a microbial desalination cell (MDC) by utilizing the mutual benefits among the above functions. When using wastewater as the sole substrate, the power output from the MDC (8.01 W/m3) was four times higher than a control MFC without desalination function. In addition, the MDC removed 66% of the salts and improved COD removal by 52% and Coulombic efficiency by 131%. Desalination in MDCs improved wastewater characteristics by increasing the conductivity by 2.5 times and stabilizing anolyte pH, which therefore reduced system resistance and maintained microbial activity. Microbial community analysis revealed a more diverse anode microbial structure in the MDC than in the MFC. The results demonstrated that MDC can serve as a viable option for integrated wastewater treatment, energy production, and desalination.

► Demonstrated a new system for integrated waste treatment, energy production, and desalination.
► Significantly increased system performance through the integration of three complementary functions.
► Analyzed the mutual benefits among the 3 different functions in BESs.
► Elucidated the effects of ion transfer on the MDC anode electrochemical and microbial activities.