Using multichannel electrochemical constructed wetlands to treat wastewater containing a mixed herbicide: efficacy...

Cross-use of herbicides in agricultural production produces multiple herbicide residues in agricultural wastewater, which makes water treatment systems less stable and specific. A multichannel electroactive constructed wetlands (EWs) system was designed in this study to treat three types of agricultural wastewaters containing herbicides: glyphosate alone (PEW), atrazine alone (AEW), and a mixture of the two herbicides (MEW). The effect of the system on the treatment of different herbicide wastewaters and the corresponding mechanism were analyzed. The best treatment effect was obtained for the MEW wastewater group with the mixed herbicide, with removal rates of the chemical oxygen demand, total nitrogen, and total phosphorus of 91.39 %, 84.93 %, and 92.70 %, respectively, as well as the lowest concentration of herbicide residues and intermediate products. The MEW system had the lowest resistance (9.13 Ω) and the highest power density (11.28 mW/m²), and the presence of plants enhanced the electrogenic performance. The MEW system enhances the ecological stochasticity and system stability of microbial communities through three main processes: integrating resources, enhancing function, and regulating metabolism. The elucidation of these mechanisms provides theoretical support and technical directions for a rural response to mixed-herbicide pollution.