Enhance performance of microbial fuel cell coupled surface flow constructed wetland by using submerged plants and enclosed anodes

Abstract

In this study, submerged plants and enclosed anodes were used to improve the performance of surface flow constructed wetland coupled microbial fuel cell system (CW-MFC). The peak cell voltage produced from CW-MFC planted with Hydrilla verticillata and equipped with enclosed anode was 558.50 mV, 66.22% higher than that of the system without these factors. Positive correlation between cell voltage and abundances of Geobacter sulfurreducens and Betaproteobacteria was obtained. Submerged plants could overcome the shortage of immoderate elongation caused by emerged plants’ roots which would ruin electrode materials, and thus enhance power generation of CW-MFC. More importantly, system with enclosed anodes showed higher cell voltage, mainly because of the higher rates of diffusion in sediments and better advection of porewater to anode materials. In addition, the planted system showed the highest NH4+-N removal rate, which was 88.92%, much higher than that of the unplanted system, which was 67.75%. In summary, submerged plants and enclosed anodes could improve the power generation of CW-MFC, along with better removal of NH4+-N.