Simultaneous sulfamethazine and Cr(VI) removal in lab-scale microbial fuel cell-constructed wetland

Microbial fuel cell (MFC) coupled constructed wetland (CW) is regarded as a promising green technology due to its simultaneous removal performance for the co-occurrence of various contaminants in wastewater. In this study, the simultaneous removal performance of sulfamethazine (SMZ) and hexavalent chromium Cr(VI) in the CW and MFCCW systems was investigated. The removal efficiencies of total nitrogen (N), total phosphorus (P), and chemical oxygen demand (COD) were also examined. The results demonstrated that Cr(VI) was effectively eliminated with an excellent removal efficiency of >98.0 %, followed by SMZ with a removal efficiency of 70.3 %-85.6 %. Additionally, during the long-term operation period, the average removal efficiency for N, P, and COD ranged from 74.0 % to 96.1 %, 83.6 % to 94.1 %, and 91.1 % to 95.3 %, respectively. The microbial community and antibiotic resistance genes (ARGs) in the anode and cathode were also analyzed separately to evaluate the SMZ and Cr(VI) removal performance of MFCCW. The abundance of corresponding ARGs was slightly different in the anode and cathode regions. The average abundance of sul4 in the SMZ+Cr(VI) treatment MFCCW was significantly higher than that of other sul1-3. This study offers valuable insights for the simultaneous removal of SMZ and Cr(VI) from wastewater by MFCCW.