(Invited) An Integrated Microbial Desalination Cell-Driven Capacitive Deionization System as an Electrochemical Means for Wastewater Treatment, Electricity Generation and Desalination

Abstract

In this study, we propose a hybrid, energy-saving electrochemical desalination system to deliver fresh water by coupling membrane capacitive deionization (MCDI) cell with microbial desalination cell (MDC) reactors. As a result, MDC produced electricity with open circuit voltage of 0.8 V and a current of 3 mA by using bacteria to degrade organic contaminants through anode bacterial oxidation and cathode reduction. In MDC, 91% removal of chemical oxygen demand (COD) in synthetic wastewater can be achieved, and the solution conductivity of salt water in desalination chamber can be reduced from 17,000 µS/cm to about 300 µS/cm. More importantly, CDI device can be directly driven by harvesting electricity from the two MDC reactors in series, and as the downstream desalination process to further desalinate the salt water. The results of this study can demonstrate the feasibility of the integrated electrochemical MDC-MCDI system for simultaneous wastewater treatment, power production, and water desalination.