Synergistic Effect of Constructed Wetland-Microbial Fuel Cell in the Treatment of Agricultural Non-Point Source Pollution

In this study, we employed a constructed wetland-microbial fuel cell (CW-MFC) for the treatment of agricultural non-point source pollution, and the impacts of CW-MFC, constructed wetland (CW), and microbial fuel cell (MFC) on agricultural non-point source pollution processing performance, electrical performance, and changes in the microbial community within the system were compared and analyzed to explore the synergistic effect of CW-MFC coupling. The findings indicated that the coupling of CW and MFC effectively enhanced the processing performance, electrical performance, and enzyme activity of CW-MFC. The electric field’s promotion of the removal rate of chemical oxygen demand (COD) and total nitrogen (TN) was greater than that of plants, while the electric field’s promotion of the removal rate of total phosphorus (TP) was smaller than that of plants. The promoting effect on the removal rate of atrazine was greater than that of plants at a low concentration of atrazine, but smaller than that of plants at medium and high concentrations of atrazine. The promoting effect of the electric field on urease (UE) and catalase (CAT) activities was generally greater than that of plants, while the promoting effect on alkaline phosphatase (ALP) activity was greater in plants. Affected by the coupling of CW and MFC, the microbial community diversity of CW-MFC and the abundance of bacterial phyla, classes, and genera such as Acidobacteria, Deltaproteobacteria, Aquabacterium, Geobacter, and Subgroup_6 were detected. The abundance of terpenoids and polyketides increased to varying extents. The results of this study laid a solid theoretical foundation for the advancement of agricultural non-point source pollution control technology and provided strong support for the expansion of CW to new application fields. It has profound significance for effectively controlling agricultural non-point source pollution and ensuring the sustainable development of agriculture.