Energy-positive Self-sustained Bioelectrochemcial Systems Treating Wastewater

The objective of this doctorate research is to explore BES application in high energy consumption wastewater treatment and substrate recovery processes--metal removal, nitrogen removal and desalination to relieve the cost of electricity in these processes and take maximum advantage of limited power generated from BES to build self-sustainable treatment systems. Firstly, a self-sustained hybrid BES consisting of microbial fuel cell (MFC) and microbial electrolysis cell (MEC) was developed to reduce multiple metals simultaneously by utilizing different reaction potentials. Three heavy metals representing spontaneous reaction (chromium, Cr) and unspontaneous reaction (lead, Pb and nickel, Ni) were selected in this batch-mode study. Secondly, an integrated short-cut nitrification and autotrophic denitrification microbial fuel cell (SNAD-MFC) was developed to achieve energy-positive nitrogen removal from wastewater to save the energy consumption and chemical input in traditional biological nitrogen removal process. Thirdly, BES was applied in the anammox process where slow growth rate of anammox bacteria was the imminent problem for system efficiency and stability. This innovative solution was explored in this study by accelerating anammox in microbial electrolysis cells (MECs) and alleviating the dependence on anammox bacteria. Finally, self-sustained hybrid system utilizing the energy produced from microbial desalination cell (MDC) was studied by integrating MDC and MEC to simultaneously remove nitrogen in wastewater and metal ions in industrial wastewater and desalinate saline water. Integrated MDC-MEC could realize the maximum utilization of BES energy and synchronous treatment of different kinds of wastewater