The Research Of C/N Removal Of Double-chamber MFC Combined With A/O Process And Its Electricity Generation Performance

Microbial fuel cell (MFC) is a device that can translate chemical energy in electrolyte into electrical energy directly by microorganism. It can be applied to wastewater treatment and energy recovery. In this paper, the double-chamber MFC combined with the A/O process was applied to nitrogen and carbon removal and its electricity generation performance was researched. The effects of different operating parameters to the double-chamber MFC reactor operations and the structure of microbial communities in different internal structure of the double-chamber MFC reactor were researched. The study can provide the scientific basis to apply microbial fuel cells in wastewater treatment. The main conclusions of the study are as follows:1. The nitrogen removal and electricity generation performance were improved significantly after 50 days to change the influent modes from sequencing batch to continuous flow when the double-chamber MFC was applied to treat the simulation wastewater. The ammonia removal rate increased from 91.68% to 95.38%. The inorganic nitrogen removal rate increased by 35.72% to 78.79%, the output voltage increased from 0.296V to 0.523±0.010V gradually. The resistance decreased from 551Ω to 293Ω. And the maximum power density increased from 0.197 W·m-3 to 0.412 W·m-3. The reactor also had good carbon removal performance. The average COD removal rate was 85.32%, the same as the previous COD removal rate nearly.2. Effects of salinity, pH, hydraulic retention time and internal circulation ratio on nitrogen and carbon removal performance and power generation were investigated. The results showed that COD removal performance of the MFC reactor was influenced by the salinity, pH and HRT obviously; ammonia removal performance of the MFC reactor ws influenced by pH and HRT obviously; NO3--N removal performance of the MFC reactor was influenced by the salinity, HRT and internal circulation ratio obviously; MFC internal resistance was influenced by salinity and HRT obviously; as well as, the maximum power density of the MFC was influenced by water salinity, water pH and internal circulation ratio obviously.3. Through the analysis of microbial community of the samples in the anode chamber electrolyte, cathode chamber electrolyte, cathode microbial membrane, the inside anode microbial membrane and the surface anode microbial membrane, the structures of microbial communities in different structures of the double-chamber MFC reactor combined with the A/O process were explored. The result showed that the microbial community compositions of samples in the anode chamber electrolyte, cathode microbial membrane, the inside anode microbial membrane and the surface anode microbial membrane were more complex than the microbial community composition of the sample in cathode chamber electrolyte. Microbial community compositions of samples in anode chamber electrolyte and cathode microbial membrane were similar. Microbial community compositions of samples in the inside anode biofilm and the surface anode biofilm were similar. The microbial community composition of sample in cathode chamber electrolyte was different greatly from other samples. Although it had electrolyte refluxing between the anode chamber and cathode chamber, the microbial community compositions in the anaerobic zone of the anode chamber and aerobic zone of the cathode chamber electrolyte was different greatly. It indicated that the biological communities in the cathode chamber electrolyte was isolated as usual, which was conducive to achieve different wastewater treatment function respectively by anode chamber and cathode chamber.