scholarly journals Real-Time Monitoring of Micro-Electricity Generation Through the Voltage Across a Storage Capacitor Charged by a Simple Microbial Fuel Cell Reactor with Fast Fourier Transform

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2610 ◽  
Author(s):  
Jung-Chieh Su ◽  
Szu-Ching Tang ◽  
Po-Jui Su ◽  
Jung-Jeng Su

The pattern of micro-electricity production of simple two-chamber microbial fuel cells (MFC) was monitored in this study. Piggery wastewater and anaerobic sludge served as fuel and inocula for the MFC, respectively. The output power, including voltage and current generation, of triplicate MFCs was measured using an on-line monitoring system. The maximum voltage obtained among the triplicates was 0.663 V. We also found that removal efficiency of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) in the piggery wastewater was 94.99 and 98.63%, respectively. Moreover, analytical results of Fast Fourier Transform (FFT) demonstrated that the output current comprised alternating current (AC) and direct current (DC) components, ranging from mA to μA.

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4712
Author(s):  
Dawid Nosek ◽  
Agnieszka Cydzik-Kwiatkowska

Development of economical and environment-friendly Microbial Fuel Cells (MFCs) technology should be associated with waste management. However, current knowledge regarding microbiological bases of electricity production from complex waste substrates is insufficient. In the following study, microbial composition and electricity generation were investigated in MFCs powered with waste volatile fatty acids (VFAs) from anaerobic digestion of primary sludge. Two anode sizes were tested, resulting in organic loading rates (OLRs) of 69.12 and 36.21 mg chemical oxygen demand (COD)/(g MLSS∙d) in MFC1 and MFC2, respectively. Time of MFC operation affected the microbial structure and the use of waste VFAs promoted microbial diversity. High abundance of Deftia sp. and Methanobacterium sp. characterized start-up period in MFCs. During stable operation, higher OLR in MFC1 favored growth of exoelectrogens from Rhodopseudomonas sp. (13.2%) resulting in a higher and more stable electricity production in comparison with MFC2. At a lower OLR in MFC2, the percentage of exoelectrogens in biomass decreased, while the abundance of genera Leucobacter, Frigoribacterium and Phenylobacterium increased. In turn, this efficiently decomposed complex organic substances, favoring high and stable COD removal (over 85%). Independent of the anode size, Clostridium sp. and exoelectrogens belonging to genera Desulfobulbus and Acinetobacter were abundant in MFCs powered with waste VFAs.


Catalysts ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1042 ◽  
Author(s):  
Paweł P. Włodarczyk ◽  
Barbara Włodarczyk

Microbial fuel cells (MFCs) are devices than can contribute to the development of new technologies using renewable energy sources or waste products for energy production. Moreover, MFCs can realize wastewater pre-treatment, e.g., reduction of the chemical oxygen demand (COD). This research covered preparation and analysis of a catalyst and measurements of changes in the concentration of COD in the MFC with a Ni–Co cathode. Analysis of the catalyst included measurements of the electroless potential of Ni–Co electrodes oxidized for 1–10 h, and the influence of anodic charge on the catalytic activity of the Ni–Co alloy (for four alloys: 15, 25, 50, and 75% concentration of Co). For the Ni–Co alloy containing 15% of Co oxidized for 8 h, after the third anodic charge the best catalytic parameters was obtained. During the MFC operation, it was noted that the COD reduction time (to 90% efficiency) was similar to the reduction time during wastewater aeration. However, the characteristic of the aeration curve was preferred to the curve obtained during the MFC operation. The electricity measurements during the MFC operation showed that power equal to 7.19 mW was obtained (at a current density of 0.47 mA·cm−2).


Author(s):  
Yakout Khadouj Jelbaoui ◽  
Lamiaa El Menzhi ◽  
Abdallah Saad

<p>Condition monitoring and on-line detection have attracted several researchers in order to carry out an efficient diagnosis of machine failures. Therefore, the detection in early stage avoids system breakdown and reduce the maintenance cost. This paper presents a new diagnosic approach to detect the broken bars and broken end ring faults for a squirrel cage induction machine based on the fast Fourier transform analysis applied on a new signature as the voltage of an auxiliary winding. The auxiliary winding is a small coil inserted between two of the stator phases, the explicit expression of its voltage is presented. The signal is monitored in six faults cases under a different load level, the emergence of the fault frequencies changes for each kind of failure. The successfully simulation results obtained show the effectiveness of this approach.</p>


Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 572 ◽  
Author(s):  
Paweł P. Włodarczyk ◽  
Barbara Włodarczyk

The possibility of wastewater treatment and electricity production using a microbial fuel cell with Cu–B alloy as the cathode catalyst is presented in this paper. Our research covered the catalyst preparation; measurements of the electroless potential of electrodes with the Cu–B catalyst, measurements of the influence of anodic charge on the catalytic activity of the Cu–B alloy, electricity production in a microbial fuel cell (with a Cu–B cathode), and a comparison of changes in the concentration of chemical oxygen demand (COD), NH4+, and NO3– in three reactors: one excluding aeration, one with aeration, and during microbial fuel cell operation (with a Cu–B cathode). During the experiments, electricity production equal to 0.21–0.35 mA·cm−2 was obtained. The use of a microbial fuel cell (MFC) with Cu–B offers a similar reduction time for COD to that resulting from the application of aeration. The measured reduction of NH4+ was unchanged when compared with cases employing MFCs, and it was found that effectiveness of about 90% can be achieved for NO3– reduction. From the results of this study, we conclude that Cu–B can be employed to play the role of a cathode catalyst in applications of microbial fuel cells employed for wastewater treatment and the production of electricity.


1977 ◽  
Vol 49 (12) ◽  
pp. 1797-1805 ◽  
Author(s):  
R. J. Schwall ◽  
A. M. Bond ◽  
R. J. Loyd ◽  
J. G. Larsen ◽  
D. E. Smith

2017 ◽  
Vol 76 (3) ◽  
pp. 683-693 ◽  
Author(s):  
Edson Baltazar Estrada-Arriaga ◽  
Yvonne Guillen-Alonso ◽  
Cornelio Morales-Morales ◽  
Liliana García-Sánchez ◽  
Erick Obed Bahena-Bahena ◽  
...  

Two different air-cathode stacked microbial fuel cell (MFC) configurations were evaluated under continuous flow during the treatment of municipal wastewater and electricity production at a hydraulic retention time (HRT) of 3, 1, and 0.5 d. Stacked MFC 1 was formed by 20 individual air-cathode MFC units. The second stacked MFC (stacked MFC 2) consisted of 40 air-cathode MFC units placed in a shared reactor. The maximum voltages produced at closed circuit (1,000 Ω) were 170 mV for stacked MFC 1 and 94 mV for stacked MFC 2. Different power densities in each MFC unit were obtained due to a potential drop phenomenon and to a change in chemical oxygen demand (COD) concentrations inside reactors. The maximum power densities from individual MFC units were up to 1,107 mW/m2 for stacked MFC 1 and up to 472 mW/m2 for stacked MFC 2. The maximum power densities in stacked MFC 1 and MFC 2 connected in series were 79 mW/m2 and 4 mW/m2, respectively. Electricity generation and COD removal efficiencies were reduced when the HRT was decreased. High removal efficiencies of 84% of COD, 47% of total nitrogen, and 30% of total phosphorus were obtained during municipal wastewater treatment.


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