Abstract:
In this study, to further improve the effectiveness of artificial wetlands in treating rural sewage, a coupled electric field vertical-flow artificial wetland system (E-VFCW) was constructed to treat raw water from the east trunk canal of Changdi Terrier Village, Panlong District, Kunming City, China, to explore its stability and purification effect and reveal the biochemical mechanism of pollutant removal from the evolutionary characteristics of microbial communities. Results indicated the following: (1) Compared to VFCW, the E-VFCW system exhibited significantly higher purification efficiency for rural wastewater, with notable increases of 7.94% in chemical oxygen demand (COD), 5.67% in total phosphorus (TP), 51.14% in ammonia nitrogen (NH
4+-N), and 27.54% in total nitrogen (TN). In particular, NH
4+-N removal rates showed significant differences (P < 0.05). (2) In the E-VFCW system, the top three dominant phyla were Proteobacteria, Bacteroidetes, and Actinobacteria, whose combined abundance accounted for approximately 80% of the total, while genera
such as
Dechloromonas, Flavobacterium, and
Pseudomonas were the predominant taxa. (3) Further examination by redundancy analysis revealed that Proteobacteria, Acidobacteria, Chloroflexi, Actinobacteria, and Nitrospirae
played pivotal roles as major drivers for COD, TN, TP, and NH
4+-N purification within the E-VFCW system. (4) Rank correlation analysis showed that electric field application promoted the enrichment and accumulation of the electroproducing bacteria such as Pseudomonas (increased by 4.76%), Hydrogenophaga (increased by 2.02%), and Flavobacteria (increased by 12.54%) in the E-VFCW system. The study showed that the combination of electric field and vertical-flow artificial wetlands could considerably filter all the conventional pollutants in rural sewage and significantly increase the relative abundance of bacteria. This study may provide theoretical guidance and a scientific basis for rural wastewater management.