Innovative pyrite-based constructed wetland-microbial fuel cell for enhancing nutrients removal and bioelectricity generation

Anode filler of constructed wetland-microbial fuel cell system (CW-MFC) was proven to have a huge impact on nutrients removal and bioelectricity generation. This study set up an innovative pyrite-based constructed wetland-microbial fuel cell (PCW-MFC) and further investigated the effect of pyrite filler on nutrients treatment efficiency, bioelectricity generation performance and functional microbial communities compared to conventional CW-MFC and PCW. The results showed that the overall processing performance of PCW-MFC was better than that of CW-MFC and PCW systems. The average removal efficiency of COD, NH4+-N, NO3−-N and TP in PCW-MFC was 88.79 ± 0.95 %, 80.39 ± 0.75 %, 89.43 ± 0.76 % and 60.49 ± 1.39 %, respectively. Meanwhile, the maximum output power density of PCW-MFC reached 123.16 mW/m3, which was 11.6 % higher than the maximum output power density of CW-MFC (110.36 mW/m3). The maximum output voltages for both were 0.478 V and 0.421 V, respectively. According to microbial community analysis, pyrite promoted the enrichment of the genera (Dechloromonas, Acinetobacter, and Thiobacillus) associated with nitrogen and phosphorus removal and the exoelectrogen Geobacter which made PCW-MFC have better electricity generation performance. This study provided ideas and theoretical support for developing and improving the performance of CW-MFC fillers.