Recent advances in improving the remediation performance of microbial electrochemical systems for contaminated soil and sediments

Remediation of contaminated soil and sediments has been drawing our attention, efficient and eco-friendly technologies are urgently needed for the removal of pollutants in soil and sediments. Although conventional remediation technologies have been in application for decades and have achieved great performance, the significant drawbacks limit their application (e.g., complicated operation and secondary pollution). Microbial electrochemical system (MES) has been intensively studied as a promising technology for soil/sediment remediation. Compared with other technologies, soil/sediment MES (SMES) exhibited many potential benefits, such as adequate electron acceptors, self-sustained operation, and facile control. However, due to the diversity of soil/sediment contamination and the significant difference in the remediation performance of conventional SMES, it is imperative to develop strategies for enhancing the remediation performance of SMES. In this review, we briefly introduce the removal mechanisms of different pollutants, including the mechanisms of electron releasing, transportation, and receiving. Afterward, we comprehensively present a detailed discussion of the recent progress in the enhancement of soil/sediment remediation in terms of reactor configurations, electrode arrangements, and electrode materials. Moreover, different materials used to amend soil/sediments and their corresponding enhancement principles are summarized in detail. Finally, we discuss the current emerging limitations of SMES and the future research endeavors to improve the performance and promote the practical application. Therefore, this review can fill the gaps in SMES development and guide the practical application in contaminated soil/sediments.