Performance and microbial community in the biocathode of microbial fuel cells under different dissolved oxygen concentrations

Huang

Env Prog and Sustain Energy

et al. 2019

The treatments of swine wastewater with variable hydraulic loading rates (HLRs) and infiltrator structure were investigated using a modified two‐stage constructed rapid infiltration system (CRIS). Furthermore, microbial community distribution at different HLRs in the CRIS was also analyzed by high‐throughput sequencing. Results indicated that when the HLR was 5.44 cm/day and 10.88 cm/day, the removal rate of chemical oxygen demand (COD) was between 68% and 73%. However, the removal rate of COD dropped to 22.3% when the HLR increased to 16.33 cm/day. Compared to the small CRIS, the removal rate of NH3‐N was stable at about 78% in the large CRIS that had ventilation in the middle of the column. In addition, at HLR 11 cm/day, majority of the taxa detected in the CRIS were assigned to Proteobacteria, Firmicutes, and Bacteroidetes. Anaerobic ammonium oxidation occurred in the middle and lower parts of the columns of CRIS. When the HLR increased to 22 cm/day, the abundance of Planctomycetes decreased from 57.48% to 38.88% in the upper layer of the first column, whereas the abundance of Firmicutes increased from 6.8% to 16.17%. Results showed the microbial community shift was observed at different HLR, influencing the pollutants removal rate. © 2019 American Institute of Chemical Engineers Environ Prog, 38: e13218, 2019

Section: Resultsmentioning

confidence: 99%

Effects of infiltrator structure and hydraulic loading rates on pollutant removal efficiency and microbial community in a modified two‐stage constructed rapid infiltration systems treating swine wastewater

Huang

Env Prog and Sustain Energy

et al. 2019

“…This fouling effect reduced the oxygen reduction at the cathode. Thus, after long‐term operation, the voltage dropped due to biofilm attachment at the C@Paper cathode surface, as shown in (Figure S4); and (Figure S5) [35–37,38] …”

Section: Figurementioning

confidence: 96%

“…Thus, after long-term operation, the voltage dropped due to biofilm attachment at the C@Paper cathode surface, as shown in (Figure S4); and (Figure S5). [35][36][37]38] In conclusion, we demonstrated, for the first time, a singleinlet spiral-shaped microfluidic microbial fuel cell (MMFC) with porous Paper@Ni anode and Paper@C cathode to generate energy using Bacillus stratosphericus bacteria as biocatalyst and glucose as substrate. The maximum power density of ∼ 150 mW cm À 2 and current density of 7 A m À 2 was obtained by pumping electrolyte-bacterial mixture solution at 0.3 ml min À 1 .…”

mentioning

confidence: 95%

Bacteria‐driven Single‐inlet Microfluidic Fuel Cell with Spiral Channel Configuration

et al. 2021

We present a single inlet, spiral‐shaped microfluidic microbial fuel cell (MFC) with porous Paper@Ni anode and Paper@C cathode for energy generation. In the MFC, the anode with a bacterial component is placed along the microchannel side to provide a larger electrode surface area, reduced internal resistance, and enhances mass transport of the 2 % glucose as a substrate for microbial redox reaction. The large electrode area induced by the spiral channel configuration and passive control of the boundary layer enhances the energy output from the fuel cell and eliminates the need for a two‐chambered system. The fuel cell utilizes bacteria Bacillus stratosphericus isolated from mangrove soil to generate bioenergy with an open‐circuit voltage of 0.3 V within 10 seconds. The fuel cell generates a maximum current density of 7 A m−2 and a power density of ∼ 150 mW m−2.

“…Genus level classification was conducted to further investigate the microbial community composition. The dominant genera identified in CFBup were affiliated with Nitrosomonas (20.4%), Sphingobacterium (8.7%), Xanthomonas (7.2%) and Flavobacterium (5.4%) (Figure 6b) It is well known that Nitrosomonas is a main nitrifying bacterium in wastewater treatment plants, where it get rid of excess ammonia by converting it to nitrite [42]. Nitrosomonas was also detected in CFBbottom, CACup, and CACbottom with a relative abundance of 3.7%, 5.4%, and 5.0%, which was much lower than that in CFBup, indicating the upper portion of carbon fiber brush biocathode was the main place for The microbial community composition in biocathode of the TB-MES was probably affected by two reasons: DO concentration and electrode material.…”

Section: Microbial Community Analysismentioning

confidence: 99%

Performance of a Trickling-Bed Biocathode Microbial Electrochemical System Treating Domestic Wastewater and Functional Microbial Community Characteristics

et al. 2020

Biocathode microbial electrochemical systems (MESs) that remove nitrogen compounds out of wastewater are of special interest for practice. High energy-input for aeration is one of the barriers that hinder their application on a wider scope. A trickling-bed biocathode MES (TB-MES) was developed by integrating biotrickling filters with a biocathode MES. By recirculating the catholyte and sprinkling it through a spray nozzle, the system was able to achieve a reoxygenation process, which could facilitate the creation of an aerobic and anoxic environment. At an optimal recirculation rate of 200 mL min−1, the TB-MES removed 87.2 ± 2.7% of ammonium nitrogen and 79.7 ± 2.5% of total nitrogen (TN), and simultaneously achieved a maximum power density of 3.8 ± 0.3 Wm−3. Comparable performances were achieved when treating domestic wastewater, which were 84.6 ± 2.4%, 70.1 ± 4.2%, and 3.2 ± 0.2 W m−3 for ammonium nitrogen removal, TN removal, and maximum power density. Pyrosequencing analysis revealed Nitrosomonas was more abundant in the upper portion of the carbon fiber brush biocathode (CFBup, 20.4%) and Azoarcus was more abundant in the lower portion (CFBbottom, 12.6%), which was probably caused by the difference in dissolved oxygen concentration in different parts of the biocathode. The TB-MES shows great promise for domestic wastewater treatment by employing biotrickling filters for oxygen supply in biocathode MES.