An overview on constructed wetland-microbial fuel cell: Greenhouse gases emissions and extracellular electron transfer

The symbiotic and complementary relationship between constructed wetlands and microbial fuel cells (termed as CW-MFC) would induce tantalizing possibilities for enhancing wastewater treatment. In this review, the per-formance of CW-MFC performed in different scenarios was discussed, and clearly indicate strengths and weak-nesses. And comprehensively summarized that the CW-MFC enhances wastewater treatment efficiency and reduces greenhouse gas emissions, primarily attributed to phytoremediation, substrate competition and domi-nance of electrogenic bacteria. Furthermore, the extracellular electron transfer involved in CW-MFC has been summarized, which is mainly classified into two types, named direct and mediated extracellular electron transfer, and the enhanced strategy has been analyzed. Notwithstanding, CW-MFC still needs more in-depth research to fill the gap with practical application and to explore further electron transfer mechanisms associated with the bacterium. Potential research areas that appear to be worth pursuing in the future for ameliorating full-scale applications are also explored to serve as a reference for further research.