In-situ remediation of contaminated groundwater by bioelectrochemical system: A review

Groundwater pollution is an important problem threatening the ecological environment and people's health, so it's very necessary to remedy the polluted groundwater. For the past few years, bioelectrochemical systems (BESs) have been widely used to remedy various polluted environments such as gas, water and solid. This is mainly attributed to following characteristics of BESs: (i) electrode can act as measureless electron acceptor/ donor; (ii) electrode surface can support the growth of microorganisms; (iii) the electric field can stimulate naturally occurring microbial degradation activity; and (iv) little or even no energy consumption. These properties enable BESs to degrade pollutants in an environmentally sustainable manner and improve the possibility of complete removal of pollutants. Therefore, this makes a lot of researchers choose to apply BESs to remediate polluted groundwater in situ. In order to fully understand BESs, this paper summarized from different aspects. Primarily, the remediation mechanism and main forms of BESs were described. Then, the application and research progress of BESs for the single and mixed pollutants removal in groundwater were reviewed. The principal variables affecting degradation performance were presented, including electrode potential, initial pollutant concentration, pH, carbon source and other process parameters and environmental conditions. Further, strategies to enhance the remediation performance of BESs were also discussed from the aspects of optimizing the system configuration, inoculating pre-enhanced microorganisms, adding redox medium and surfactant. Finally, the potential research direction of removing groundwater pollutants by BESs was proposed.