VFCW-MFC for simultaneous decontamination and electricity production under sulfadiazine stress: Effects of substrates and analysis of bacterial community structure

Abstract

s Swine wastewater contains high concentrations of organic matter, nutrients and antibiotics, posing a major environmental challenge. The functional microbial community structure related to decontamination and electricity production is studied using Vertical Flow Constructed Wetland-Microbial Fuel Cell (VFCW-MFC) with zeolite, biochar and zeolite + biochar (volume ration 1:1) as substrates. The results show that the average removal efficiencies of conventional pollutants (Chemical Oxygen Demand (COD), ammonia nitrogen and Total Phosphorus (TP)) are higher than 93 % and sulfadiazine (SDZ) is higher than 82 %. Zeolite and zeolite + biochar substrates are beneficial to remove Total Nitrogen (TN), and the removal efficiency is 44.14 % and 39.55 % higher than that of biochar alone. VFCW-MFC has good power generation performance, its voltage ( U ), power density ( P A ), coulombic efficiency ( CE ) and net energy recovery ( NER ) are up to 454.86 mV, 4.22 mW/m 2 , 55.56 % and 2.16 W/(g s). The microbial richness in the anode of VFCW-MFC with zeolite as substrate is significantly higher than that with biochar as the substrate. There is no significant difference in microbial richness and diversity in the cathode region of VFCW-MFCs. The predominant phyla Proteobacteria , Bacteroidota , Firmicutes and Actinobacteria are good SDZ degrading microorganisms. Proteobacteria and Firmicutes are the predominant phyla of electricity production. Nitrospira and Turicibacter at genus level can promote nitrification and denitrification, thereby reducing the nitrogen content in wastewater.