Effect of air-exposed biocathode on the performance of a Thauera-dominated membraneless single-chamber microbial fuel cell (SCMFC)
Nuan Yang , Guoqiang Zhan , Tingting Wu , Yanyan Zhang , Qinrui Jiang , Daping Li , Yuanying Xiang
DOI:10.1016/j.jes.2017.05.013
Received February 13, 2017,Revised May 08, 2017, Accepted May 09, 2017, Available online May 12, 2017
Volume 30,2018,Pages 216-224
To investigate the effect of air-exposed biocathode (AEB) on the performance of single-chamber microbial fuel cell (SCMFC), wastewater quality, bioelectrochemical characteristics and the electrode biofilms were researched. It was demonstrated that exposing the biocathode to air was beneficial to nitrogen removal and current generation. In Test 1 of 95% AEB, removal rates of ammonia, total nitrogen (TN) and chemical oxygen demand (COD) reached 99.34% ± 0.11%, 99.34% ± 0.10% and 90.79% ± 0.12%, respectively. The nitrogen removal loading rates were 36.38 g N/m3/day. Meanwhile, current density and power density obtained at 0.7 A/m3 and 104 mW/m3 respectively. Further experiments on open-circuit (Test 2) and carbon source (Test 3) indicated that this high performance could be attributed to simultaneous biological nitrification/denitrification and aerobic denitrification, as well as bioelectrochemical denitrification. Results of community analysis demonstrated that both microbial community structures on the surface of the cathode and in the liquid of the chamber were different. The percentage of Thauera, identified as denitrifying bacteria, maintained at a high level of over 50% in water, but decreased gradually in the AEB. Moreover, the genus Nitrosomonas, Alishewanella, Arcobacter and Rheinheimera were significantly enriched in the AEB, which might contribute to both enhancement of nitrogen removal and electricity generation.
