CW-MFC technology for wastewater remediation: Antibiotic reduction, gas emission mitigation, and bioenergy production

Abstract

This study aimed to remove antibiotic residues from wastewater and assess greenhouse gas emissions, energy generation, and chlorophyll production using microbial fuel cells combined with constructed wetlands (CW-MFC). Two hydraulic retention times (HRT) of one and two days, two types of electrodes—graphite and bio-electrodes—and a control with no electrodes were employed. The results indicated complete removal of Tetracycline (TET) within three days and over 98.0% removal of Norfloxacin (NOR) in all treatments, with no significant differences in their removal (p > 0.05). For Chloramphenicol (CHL), the two-day HRT was more effective (85.2%) than the one-day HRT (68.1%) (p = 1.11e-06). Significant differences were observed regarding ammonium, with better results for the two-day HRT and in the order control > graphite > bioelectrode (p = 0.00758). Chlorophyll production was higher in the wetlands with bioelectrode and two-day HRT (55.6 SPAD) than in the graphite electrode. Regarding gas emissions, CW-MFC treatments reduced CO2 and H2S emissions more effectively than the control group, which released lower oxygen levels. Lastly, wetlands with bioelectrodes achieved the highest potential differences: bioelectrode2 (0.22 ± 0.12 mV) and bioelectrode1 (0.16 ± 0.02 mV). These findings demonstrate the potential of CW-MFC technology, optimized with HRT and bioelectrodes, for efficient antibiotic removal, greenhouse gas mitigation, and bioenergy generation. Integrating microbial fuel cells with constructed wetlands achieved over 98.0% antibiotic removal, enhanced ammonium reduction, and increased chlorophyll production. CW-MFC systems emerge as a sustainable and effective alternative to conventional wastewater treatment.