Effects of aeration coupled with microbial fuel cell on nitrogen removal and electricity production for biogas slurry

Microbial fuel cell (MFC) can be used as a potential technology for degradation of organic contaminant. In order to improve the efficiency of MFC treating the biogas slurry (BS), a comparison between the pretreatments of aerobic static culture and aeration was studied. The nitrogen and chemical oxygen demand (COD) removal and electricity production capacity of BS-MFC was investigated. The results showed that the total degradation rate of NH4+-N in BS after the aeration coupled with MFC treatment reached 95.70 %, which was 12.97 % higher than that of the aerobically statically cultivated BS. The coulombic efficiency (CE) of the aeration-treated BS participating the reaction in MFC was always higher than that of the aerobically cultivated group. The relative abundance of Chloroflexi, which plays an important role in nitrogen metabolism, accounted for a smaller proportion in the MFC reaction effluent after aeration treatment. While, the denitrification bacteria Patescibacteria was slightly enhanced. The aeration-treated BS also stimulated the growth of electrochemically active microorganisms Gammaproteobacteria in the MFC system. The results of this study showed that pretreatment of the BS with aeration was more favorable to improve the efficiency of the BS-MFC, which provided informative suggestions for the improvement of MFC.