The Comparison of Substrate Changes in Microbial Fuel Cells Using Excess Sludge and Simple Anaerobic Digestion

2013 ◽  
Vol 864-867 ◽  
pp. 1839-1842
Author(s):  
Xiao Qin Zhao ◽  
Xiao Jie Sun ◽  
Su Na Wei ◽  
Jiang Cheng Liang ◽  
Yang Yang ◽  
...  

Based on the previous studies, this experiment presented a new kind of microbial fuel cells (MFC), single-chamber air cathode microbial fuel cells without proton membrane. After investigating the contrast of substrate changes in microbial fuel cells and simple anaerobic digestion, the analysis results of soluble chemical oxygen demand (SCOD), TP, TN and NH3-N show that: SCOD increase firstly, then decrease, to the end, descend. As a result, we find that SCOD in MFC is lower than that in control device (CD). Throughout the whole reaction period, TP in MFC is lower than that in CD. TN and NH3-N show upward trend after a reaction period.

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 379
Author(s):  
Ignacio T. Vargas ◽  
Natalia Tapia ◽  
John M. Regan

During the last decade, bioprospecting for electrochemically active bacteria has included the search for new sources of inoculum for microbial fuel cells (MFCs). However, concerning power and current production, a Geobacter-dominated mixed microbial community derived from a wastewater inoculum remains the standard. On the other hand, cathode performance is still one of the main limitations for MFCs, and the enrichment of a beneficial cathodic biofilm emerges as an alternative to increase its performance. Glucose-fed air-cathode reactors inoculated with a rumen-fluid enrichment and wastewater showed higher power densities and soluble chemical oxygen demand (sCOD) removal (Pmax = 824.5 mWm−2; ΔsCOD = 96.1%) than reactors inoculated only with wastewater (Pmax = 634.1 mWm−2; ΔsCOD = 91.7%). Identical anode but different cathode potentials suggest that differences in performance were due to the cathode. Pyrosequencing analysis showed no significant differences between the anodic community structures derived from both inocula but increased relative abundances of Azoarcus and Victivallis species in the cathodic rumen enrichment. Results suggest that this rarely used inoculum for single-chamber MFCs contributed to cathodic biofilm improvements with no anodic biofilm effects.


2014 ◽  
Vol 535 ◽  
pp. 141-144
Author(s):  
Xiao Qin Zhao ◽  
Xiao Jie Sun

A single-chamber and membrane-less microbial fuel cells (MFC) was successfully started up using anaerobic sludge as inoculums without any nutrient elements for 20 d. Under 30 °C, excess sludge SS was about 21000 mg·L-1, anode area for 31.4 cm2and in 200 mM NaCl concentration agent conditions experiment MFC, while the control device (CD) directly with original sludge anaerobic digestion. The electricity generation of microbial fuel cell and the contrast of substrate changes were investigated. The results show that obtained maximum voltage is 597.3 mV, pH in MFC is slightly higher than in contrast test. Volume reduction in MFC is larger than the controls. Reducing sugar in MFC is lower than that in CDs. Proteins increase at first and then decrease, finally there is no significant difference in both of MFC and CD. Key words: Microbial Fuel Cells, Excess Sludge, Anaerobic Digestion, Reutilization


2017 ◽  
Vol 56 (44) ◽  
pp. 12471-12478 ◽  
Author(s):  
Didac Recio-Garrido ◽  
Ademola Adekunle ◽  
Michel Perrier ◽  
Vijaya Raghavan ◽  
Boris Tartakovsky

2009 ◽  
Vol 75 (11) ◽  
pp. 3389-3395 ◽  
Author(s):  
Yifeng Zhang ◽  
Booki Min ◽  
Liping Huang ◽  
Irini Angelidaki

ABSTRACT Electricity generation from wheat straw hydrolysate and the microbial ecology of electricity-producing microbial communities developed in two-chamber microbial fuel cells (MFCs) were investigated. The power density reached 123 mW/m2 with an initial hydrolysate concentration of 1,000 mg chemical oxygen demand (COD)/liter, while coulombic efficiencies ranged from 37.1 to 15.5%, corresponding to the initial hydrolysate concentrations of 250 to 2,000 mg COD/liter. The suspended bacteria found were different from the bacteria immobilized in the biofilm, and they played different roles in electricity generation from the hydrolysate. The bacteria in the biofilm were consortia with sequences similar to those of Bacteroidetes (40% of sequences), Alphaproteobacteria (20%), Bacillus (20%), Deltaproteobacteria (10%), and Gammaproteobacteria (10%), while the suspended consortia were predominately Bacillus (22.2%). The results of this study can contribute to improving understanding of and optimizing electricity generation in microbial fuel cells.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3987
Author(s):  
Asimina Tremouli ◽  
Theofilos Kamperidis ◽  
Gerasimos Lyberatos

Four multiple air–cathode microbial fuel cells (MFCs) were developed under the scope of using extracts from fermentable household food waste (FORBI) for the production of bioelectricity. The operation of the MFCs was assessed in batch mode, considering each cell individually. Τhe chemical oxygen demand (COD) efficiency was relatively high in all cases (> 85% for all batch cycles) while the electricity yield was 20 mJ/gCOD/L of extract solution. The four units were then electrically connected as a stack, both in series and in parallel, and were operated continuously. Approximately 62% COD consumption was obtained in continuous stack operation operated in series and 67% when operated in parallel. The electricity yield of the stack was 2.6 mJ/gCOD/L of extract solution when operated continuously in series and 0.7 mJ/gCOD/L when operated continuously in parallel.


2017 ◽  
Vol 11 (1) ◽  
pp. 36
Author(s):  
Melly Mellyanawaty ◽  
Chandra Wahyu Purnomo ◽  
Wiratni Budhijanto

Penelitian ini bertujuan untuk mengetahui pengaruh penambahan zeolit alam termodifikasi sebagai media imobilisasi terhadap dekomposisi material organik pada proses anaerobic digestion. Modifikasi yang dilakukan adalah dengan cara mengimpregnasi ion besi(Fe2+)ke dalam zeolit yang telah dibentuk menjadi cincin Raschig. Impregnasi yang dilakukan adalah impregnasi basah. Dalam penelitian ini digunakan 3 variasi konsentrasi larutan Fe2+ yaitu 10 mg/L; 100 mg/L dan 2000 mg/L. Dari hasil impregnasi zeolit menggunakan ketiga konsentrasi tersebut diperoleh kadar Fe2+ yang terdeposit ke dalam zeolit berturut-turut: 0,0016 mgFe2+/gZeo; 0,0156 mgFe2+/gZeo; 0,3125 mgFe2+/gZeo dan 0 mgFe2+/gZeo digunakan sebagai kontrol. Zeolit termodifikasi Fe2+ kemudian ditambahkan ke dalam reaktor anaerobik yang dijalankan secara batch. Perbandingan volume media zeolit dan cairan adalah 1:1. Substrat yang digunakan berupa campuran limbah distillery spent wash dengan konsentrasi soluble Chemical Oxygen Demand (sCOD) 10.000 mg/L dan keluaran dari digester aktif kotoran sapi sebagai inokulum. Perbandingan volume distillery spent wash terhadap inokulum sebesar 2:1. Proses anaerobik dijalankan selama 28 hari.Jika dibandingkan dengan data Total Solid (TS) dan Volatile Solid (VS), hasil percobaan menunjukkan bahwa data analisis sCOD memberikan data yang lebih akurat dan konklusif untuk mengukur perubahan material organik dalam proses peruraian anaerobik menggunakan media imobilisasi. Dari keempat variasi kadar Fe2+ yang digunakan dalam penelitian ini, Fe2+ dengan kadar 0,0156 mgFe/gZeo memberikan efisiensi penurunan material organik (sCOD) tertinggi yaitu 66,73%. Sedangkan Fe2+ dengan kadar 0,3125 mgFe/gZeo mampu meningkatkan produksi biogas sebesar 43%. Namun secara keseluruhan proses peruraian anaerobik yang menggunakan zeolit termodifikasi Fe2+ menghasilkan biogas lebih banyak daripada kontrol (zeolit tanpa Fe2+).


2003 ◽  
Vol 48 (3) ◽  
pp. 143-150 ◽  
Author(s):  
C. Yangin Gomec ◽  
R.E. Speece

The effect of pH on anaerobic solubilization of domestic primary sludge and activated sludge was investigated and compared. Anaerobic solubilization was carried out in continuously stirred anaerobic reactors at mesophilic temperature (35°C) and pH was fixed at 6.5 (pH-controlled). Many researches reported the serious effects of pH on the solubilization of organic materials. Thus, the aim of pH control in the reactors consisting of domestic primary and activated sludges, was the evaluation of retardation in hydrolysis/acidogenesis at low pH values. Since primary and activated sludges have different biodegradation characteristics, results were compared. Results indicated that the destruction of Total Suspended Solids (TSS) and Volatile Suspended Solids (VSS) were better in the pH-controlled reactors. In both sludges, acetic acid was the main Volatile Fatty Acid (VFA) produced. In the pH-controlled reactors, VSS reduction was found to be 72% in about 20 days in the anaerobic digestion of activated sludge, whereas for the same interval VSS reduction could only be achieved by 32% in primary sludge at 35°C. When primary sludge was used as substrate, the pH-uncontrolled and the pH-controlled reactors removed VSS with a corresponding production of VFAs and Soluble Chemical Oxygen Demand (SCOD). However, production of VFAs and SCOD was ceased after 5 days in the pH-controlled reactor whereas VFAs and SCOD production continued after 5 days in the pH-uncontrolled reactor, which indicated that hydrolysis and fermentation did not complete and continued longer. On the other hand; in either the pH-uncontrolled or the pH-controlled reactor of activated sludge, VSS was not removed with a corresponding production of VFAs and Soluble Chemical Oxygen Demand (SCOD). It was apparent that solubilization was occurring, however this solubilization was not observed as VFA production. When total methane production and total COD (CODtot) removal were estimated using VSS removal in both types of sludges, results indicated that pH control enhanced biogas productions as well as CODtot removals.


2013 ◽  
Vol 864-867 ◽  
pp. 1333-1336 ◽  
Author(s):  
Ling Ling Wang ◽  
De Dong Sun ◽  
Jing Jing Ren ◽  
Chun Ma ◽  
Jun Hao ◽  
...  

This article focuses on the effects of pretreatment on sewage sludge with sodium hypochlorite addition. The solubilization of organic matters of sludge was investigated. It was found that the pypocholoride treatment provided a efficient process to release organics from sludge flocs. When the ClO-dose was about 21mg /g SS with a reaction time of 3 hours, the supernatant soluble chemical oxygen demand (SCOD), total nitrogen (TN), total phosphorus (TP), protein and polysaccharide increased by 400%, 67%, 1791%, 635%, 214%, and 556%, respectively. After hypochlorite pretreatment, the sludge extracelluar polymers (EPS) were disintegrated and the cell walls were broken. Then the intracellular organic matters were released into the supernatant, leading to the increase of organic matters in the supernatant.


Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4735
Author(s):  
Szymon Potrykus ◽  
Sara Mateo ◽  
Janusz Nieznański ◽  
Francisco Jesús Fernández-Morales

The energy contained in wastewaters has been identified as a promising sustainable energy resource that could be harvested by using microbial fuel cells (MFC). When dealing with real wastewaters, the MFCs should be able to manage high flow rates and flow rates fluctuations. In this work, the short-term effects of the influent flow rate variations on the performance of a microbial fuel cell has been studied. With this aim, the influent flow rate was stepwise increased from 0.72 to 7.2 L/d and then stepwise decreased. The obtained results indicate that, on the one hand, an increase in the influent flow rate leads to higher chemical oxygen demand removal rates up to 396 g/(L/d) and higher electric power generation almost 18 mW/m2, but to lower coulombic efficiencies. On the other hand, the reduction of the flow rate increases the coulombic efficiencies, as well as the percentage of chemical oxygen demand removed, but decreases electric power generation. In the short-term, the exposition to higher influent flow rates causes the growth of the microbial population of the MFC, the growth of the non-electrogenic microorganisms being higher than that of the electrogenic ones. The higher growth of non-electrogenic microorganisms may lead to lower coulombic efficiencies.


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