Closed Circuit Operation Research Articles

Utilization of Spent Coffee Grounds for Bioelectricity Generation in Sediment Microbial Fuel Cells.

This study examined the utilization of spent coffee grounds with different aqueous extraction methods for the bioelectricity generation from coastal benthic sediment through a sediment microbial fuel cell (SMFC) system. Different methods for the aqueous extraction of SCGs were evaluated, including rinsing and drying of the SCG (SMFC-CRD), immersion, rinsing and drying (SMFC-CRID), drying alone (SMFC-CD), and untreated SCG (SMFC-C). The caffeine concentration in the SCG was significantly reduced using pretreatments, with SMFC-CRID achieving the lowest concentration of 0.021 ± 0.001 mg/g. SMFC-CRD contributed to the generation of the highest current density of 213.7 mA/m2 during closed-circuit operation and exhibited the highest power density of 96.9 mW/m2 in the polarization test, due to the suitable caffeine content of 0.275 ± 0.001 mg/g in the SCG. This study could provide a cost-effective method for reusing SCGs (i.e., 128 g) while generating bioelectricity as an alternative energy source. These results suggest that pretreatment with SCGs is essential for achieving optimal power density and reducing the caffeine concentration in the SMFC system.

Conductive materials and applied potential to augment methanogenesis for biogas upgradation: Acidogenic synergy, CO2 dynamics and sustainability analysis

Methane (CH4) and carbon dioxide (CO2) make up the majority of the raw biogas produced by anaerobic digestion (AD). Increasing the process intensity by concurrently consuming CO2 in the presence of electron donors will enhance the gross calorific value of the biogas. The use of conductive materials (CM) and an electro-methanogenic (EM) process was evaluated to study carbon conversion efficiency to CH4 with simultaneous biogas upgradation. Five reactors (R1-control; R2-Granular Activated Carbon (GAC); R3- Nano Zero Valent Iron (NZVI); R4- Closed Circuit (CC); R5-Applied Potential (AP)) were operated using glucose as a source of carbon (30 g/L) to relatively examine the sustainable effect of CM and EM on methanogenesis. Higher biogas yield with higher CH4 production and accumulation of acetic acid was observed more in the NZVI system followed by AP, CC, GAC, and Control operation. NZVI supplemented significantly added to biogas upgradation (7.6 L) with a concurrent CO2 decrease (87%) as compared to the GAC (3.868 L, 43%) and EM (AP, 4.89 L, 52%; CC, 4.73 L, 49%) but its sacrificial and oxidation nature offsets its translation potential. The electron flux generated in AP and CC reactors had a strong regulatory effect that increased CO2 conversion and utilization towards CH4 compared to other circumstances. The genus-level metagenomic analysis showed a predominance of Clostridium, Ruminococcus, and Acetobacter species in all the reactors except the control. The life cycle assessment (LCA) analysis depicted that the system variation studied showed relatively low CO2 emission in the test condition with NZVI showing the least emission followed by AP and CC. This work offers a method for improving overall CH4 production while overcoming the constraints in methanogenesis, using the influence of in situ carbon flux making the process sustainable.

Free vibration and nonlinear dynamic response of sandwich plates with auxetic honeycomb core and piezoelectric face sheets

This article analyses the nonlinear dynamic behavior and the free vibration of a piezoelectric auxetic honeycomb sandwich plate resting on a Pasternak elastic substrate. The plate includes two face sheets of piezoelectric material and an auxetic honeycomb core with a negative Poisson ratio. The first-order shear deformation plate theory, together with the von Kármán type nonlinear strain-displacement relationship, is used to establish the nonlinear equations of motion. Linear electric potential change with piezoelectric layer thickness is assumed. Two types of boundary conditions, namely immovable and movable simply supported, are considered. The displacement-time and acceleration-displacement curves under dynamic loads are determined by using the Galerkin and Runge-Kutta fourth-order methods. Verification examples have been performed and confirmed the accuracy of the model. Finally, several novel investigations have been conducted to evaluate the effect of material, geometrical parameters, and elastic substrate coefficients on the frequency and nonlinear dynamic characteristics of piezoelectric auxetic honeycomb sandwich plates for both open-circuit and closed-circuit operation.

Determination of Electrogenic Potential and Removal of Organic Matter from Industrial Coffee Wastewater Using a Native Community in a Non-Conventional Microbial Fuel Cell

Microbial fuel cells (MFCs) are an alternative to conventional wastewater treatments that allow for the removal of organic matter and cogeneration of electrical energy, taking advantage of the oxidation–reduction metabolism of organic compounds conducted by microorganisms. In this study, the electrogenic potential and the capacity for the reduction of the organic matter of native microbial communities in wastewater from the wet processing of coffee were evaluated using open-cathode MFCs. To determine the electrogenic potential, a factorial experimental design was proposed in which the origin of the residual water and the source of the inoculum were evaluated as factors. The MFCs operated for 21 days in both open-circuit and closed-circuit operation modes. Voltage records, current determinations, and chemical oxygen demand (COD) analyses were used to establish the power reached in the electrochemical system and the degree of the decontamination of the wastewater. During the MFC operation, voltages from 200–400 mV and power and current densities from 300–900 mW·m−2 and 10–22 mA·m−2, respectively, were reached. The inoculum used, with a statistical significance of α < 0.05, influenced the electrogenic performance of the microbial fuel cell. The previous process of adaptation to the operational conditions of the MFCs of the native microbial community positively influenced the current generation in the system. The degradation rates reached 500–600 mg·L−1·day−1, indicating the metabolic capacity of the microbial community in the MFCs to achieve the decontamination of wastewater from the coffee agroindustry. It was shown the implementation of bioelectrochemical systems constituted a viable option for the treatment of agricultural waste in Colombia. In addition, it was observed the capacity to cogenerate electrical energy from the biotransformation of the polluting organic matter in the effluents of the coffee industry.

Application of Low-Cost Plant-Derived Carbon Dots as a Sustainable Anode Catalyst in Microbial Fuel Cells for Improved Wastewater Treatment and Power Output

Microbial fuel cells (MFC) can generate electric energy from wastewater which can be enhanced further by anode catalysts. The recovery of electrons produced by oxidation of organics catalyzed by bacteria in the anode was enhanced when carbon dots(CDs) were added into the MFC. In this present study, a novel strategy for designing anode material and the fabrication of a high-efficient and environmentally friendly anode for energy generation from wastewater was reported. The CDs were synthesized by the pyrolysis of a peanut shell at the temperature of 250 °C for 2 h with a heating rate of 10 °C min−1. Thus synthesized CDs were characterized by transmission electron microscopy (TEM), UV/Vis spectroscopy, and fluorescence spectroscopy. The TEM analysis showed morphology with an average size of 1.62 nm. The UV/Vis absorbance of the CDs shows a wide absorption band without a characteristic peak. The excitation spectrum of CDs recorded at the emission wavelength of 440 nm exhibits a peak around 320 nm. CDs were investigated as an anode material in a MFC utilizing acetate as the organic substrate. The average chemical oxygen demand (COD) removal in closed circuit operation mode was 89%. The maximum power density production (7.2 W/m3) was observed in MFC containing 1 mg/cm2 CD-impregnated anode (CDsIA). The CDsIA provides the ability to promote efficient biofilm formation. These results emphasize the application of CD-based electrodes in MFCs for the simultaneous treatment of wastewater and electricity generation while also providing additional benefits.

Performance of bioelectrochemical systems in treating exhaust gas with power generation: Effects of shock-load, shut-down episodes and microbial community

A diffusive packed anode-bioelectrochemical (Dpa-Bes) system was constructed by feeding waste gas from the cathode to the anode tank in DPa-Bes through a proton exchange membrane (PEM). The high removal of oxygen by the PEM and the effective combination of the two packing materials reduced the electron loss and enhanced the proton transfer capacity, promoting the removal of acetone from the exhaust gas and increasing the output power. The maximum acetone removal efficiency of the modified Dpa-Bes reached ∼99 % after seven days of closed-circuit operation, with a 3.2-fold increase in maximum power density and a 2.27-fold increase in closed-circuit voltage relative to those of the unmodified Dpa-Bes. When the acetone concentration was 2400 ppm, the removal efficiency was 73.22 % and the elimination capacity was at its highest value of 290.21 g/m3/h. Microbial analysis revealed that the conductive filter contained abundant facultative and anaerobic bacteria, whereas the non-conductive filter was rich in aerobic bacteria. The abundance of anaerobic and facultative microorganisms in Dpa-Bes was much higher than in the unmodified Dpa-Bes, and the dominant bacteria were Flavobacterium and Ferruginibacter.

Enhancing quorum sensing in biofilm anode to improve biosensing of naphthenic acids

The feasibility of enhancing quorum sensing (QS) in anode biofilm to improve the quantifications of commercial naphthenic acid concentrations (9.4–94 mg/L) in a microbial electrochemical cell (MXC) based biosensor was demonstrated in this study. First, three calibration methods were systematically compared, and the charging-discharging operation was selected for further experiments due to its 71–227 folds higher electrical signal outputs than the continuous closed-circuit operation and cyclic voltammetry modes. Then, the addition of acylase (5 μg/L) as an exogenous QS autoinducer (acylase) was investigated, which further improved the biosensor's electrical signal output by ∼70%, as compared to the control (without acylase). The addition of acylase increased the relative expression of QS-associated genes (lasR, lasI, rhlR, rhlI, lasA, and luxR) by 7–100%, along with increased abundances of known electroactive bacterial genera, such as Geobacter (from 42% to 47%) and Desulfovibrio (from 6% to 11%). Furthermore, toxicities of different NAs concentrations measured with the Microtox bioassay test were correlated with corresponding electrical signals, indicating that MXC-biosensor can provide a dual platform for rapid assessment of both NA concentrations and NA-associated toxicity.

Mechanistic modeling and simulation of grinding iron ore pellet feed in pilot and industrial-scale ball mills

Various approaches have been used over the years to describe quantitatively ball milling, with different levels of success. The present work presents the application and validation of a mechanistic model to describe ball milling of iron ore pellet feed. The approach started by estimating selected parameters describing the ore characteristics by back-calculation from batch grinding tests, followed by validation of the model in batch grinding as well as continuous open-circuit ball milling at a pilot-scale operating at a variety of solids concentrations, both with overflow and grate discharge. An industrial ball mill was then laser scanned and surveyed, including measurements of residence time distribution. Simulations using the discrete element method were then conducted and the model was applied to simulate closed-circuit operation, resulting in good agreement between measured and predicted size distributions and circulating load ratio.

Seasonal variations of pollutants removal and microbial activity in integrated constructed wetland–microbial fuel cell systems

Abstract This study investigated the seasonal variations of pollutants removal and microbial activity in constructed wetland–microbial fuel cell systems (CW–MFCs). The results showed that the atmospheric temperature significantly influenced the bioelectricity generation and removal of organics and nitrogen in CW–MFCs by primarily influencing the microbial enzymatic activity. The electricity output of CW-MFCs was extremely low below 5 °C, and reached the maximum above 25 °C. The organics and nitrogen removal of closed-circuit CW–MFC reached the highest in summer and autumn, followed by spring, and decreased by an average of 10.5% COD, 14.2% NH3-N and 10.7% TN in winter, demonstrating smaller seasonal fluctuations compared to open-circuit CW–MFC in which the difference between summer and winter was 13.4% COD, 15.1% NH3-N and 15.1% TN. Even at low temperatures, the MFC current could enhance the enzymatic activity and stabilize the growth of microorganisms on the electrodes, moreover, the closed circuit operation can promote the bacteria diversity on CW–MFC anodes as well as the abundance of electrogens on CW–MFC anodes and cathodes, and thus reduce the adverse effect of cooling on organics and nitrogen removal in CWs. However, neither MFC nor temperature had a significant influence on phosphorus removal in CW–MFCs.

Development of 66kV Isolation Switch V Type Porcelain Column Fracture Insulation Protection Frame

The mechanical strength of old 66kV disconnect switches (V-type porcelain column type) in outdoor substations has been affected by weather and daily operation for a long time, and the change of internal force of porcelain column caused by external force during open and closed circuit operation is very likely to cause porcelain column fracture, which poses a safety hazard to the safety of people and equipment. In order to ensure the safety of personal and equipment during operation and maintenance of the switch, this paper proposes a kind of insulation protection frame for 66kV disconnecting switch V-type porcelain column fracture. The simple structure, flexible operation, safety and reliability of this protective frame have been proved by practice that after using this protective frame in work, the efficiency of work is obviously improved and the safety of personal and equipment is effectively guaranteed.

Boosting the cathode function toward the oxygen reduction reaction in microbial fuel cell using nanostructured surface modification

AbstractProduction of bioelectricity via microbial fuel cells (MFCs) may become an important source of energy in the near future due to the possibility of extracting electric current from a wide range of organic wastes. In this study, several nanostructures, such as platinum (Pt)‐reduced graphene oxide nanocomposite, graphene nanosheets, MnO2, and MnO2/RGO, were synthesized, characterized, and investigated as cathode catalysts for oxygen reduction reaction. The prepared catalysts were tested in a single‐chamber microbial fuel cell with anaerobic bacterial mixed culture. Power density produced from MFC closed circuit operation using the nanoengineered catalysts were about 68 times more than those obtained using the classical graphite electrodes. Moreover, there was a slight reduction of 5.8% in power density (from 170 to 160 mW/m2) when Pt nanoparticles were loaded on the RGO nanosheets compared to Pt/C cathode. By replacing the precious Pt catalyst with other nanomaterials, a significant reduction in power density was observed. For RGO‐based cathode, the MFC performance decreased by 31.1% (from 170 to 117 mW/m2) and the percent of reduction reached 48.5% (from 170 to 88 mW/m2) for MnO2‐based cathode MFC. However, in RGO/MnO2 nanocomposite cathode MFC, the percent of reduction in power density was 26.4% (from 170 to 125 mW/m2). It can be concluded that RGO nanosheets loaded with Pt nanoparticles is a starting point for finding an alternative economic and effective cathode.

Electrogenic Biofilm Development Determines Charge Accumulation and Resistance to pH Perturbation

The electrogenic biofilm and the bio-electrode interface are the key biocatalytic components in bioelectrochemical systems (BES) and can have a large impact on cell performance. This study used four different anodic carbons to investigate electrogenic biofilm development to determine the influence of charge accumulation and biofilm growth on system performance and how biofilm structure may mitigate against pH perturbations. Power production was highest (1.40 W/m3) using carbon felt, but significant power was also produced when felt carbon was open-circuit acclimated in a control reactor (0.95 W/m3). The influence of carbon material on electrogenic biofilm development was determined by measuring the level of biofilm growth, using sequencing to identify the microbial populations and confocal microscopy to understand the spatial locations of key microbial groups. Geobacter spp. were found to be enriched in closed-circuit operation and these were in close association with the carbon anode, but these were not observed in the open-circuit controls. Electrochemical analysis also demonstrated that the highest mid-point anode potentials were close to values reported for cytochromes from Geobacter sulfurreductans. Biofilm development was greatest in felt anodes (closed-circuit acclimated 1209 ng/μL DNA), and this facilitated the highest pseudo-capacitive values due to the presence of redox-active species, and this was associated with higher levels of power production and also served to mitigate against the effects of low-pH operation. Supporting carbon anode structures are key to electrogenic biofilm development and associated system performance and are also capable of protecting electrochemically active bacteria from the effects of environmental perturbations.

Microbial electrochemical biosensor for rapid detection of naphthenic acid in aqueous solution

Abstract In processed water generated from oil sands operations, naphthenic acids (NAs) are identified as one of the primary sources of acute toxicity and were assessed for their endocrine-disrupting potentials. Hence, the monitoring of NAs in aqueous environmental matrices is crucial for oil sands and crude oil production industries. Commonly used analytical methods for NAs include Fourier transform infrared spectroscopy, gas chromatography–mass spectrometry, and high-performance liquid chromatography. However, these methods are time-consuming, expensive, and samples must be sent to an analytical lab for analysis. In this study, we first demonstrated microbial electrochemical cell (MXC)-based biosensor for the rapid detection of a model NA compound (cyclohexane carboxylic acid) in water samples. Under the continuous closed-circuit operation of MXC biosensor, electrical responses (peak currents) were fairly proportional (R2 = 0.64) to the model NA concentrations ranging from 50 to 250 mg COD/L. However, the charging-discharging operation of biosensor significantly increased the peak currents by 90–124 folds higher than that observed for continuous closed-circuit operation. Besides, a linear relationship between model NA concentrations and the peak currents (R2 = 0.96) was observed. Furthermore, it has been revealed that the biosensor would be sensitive to salinity levels and temperature changes; however, once calibrated it can be used for measurement of model NA concentrations. Overall, the results of this study demonstrated that with further development, MXC biosensor could be used as a simple bioanalytical tool for monitoring NA concentrations in oil sands process-affected water.

Accumulation of sulfonamide resistance genes and bacterial community function prediction in microbial fuel cell-constructed wetland treating pharmaceutical wastewater

Microbial fuel cell constructed wetlands (CW-MFCs) with different circuit operation conditions and hydraulic retention time (HRT) were constructed to evaluate their ability to remove and accumulate pharmaceutical and personal care products (PPCPs) (sulfadiazine (SDZ), carbamazepine (CBZ), naproxen (NPX) and ibuprofen (IBP)) during four months running process. The abundance level of corresponding sulfonamide antibiotic resistance genes (ARGs) was also investigated. The results showed that closed circuit operation of CW-MFC contributed to the decrease in mass loading of COD, NH4+-N, PPCPs, and wastewater toxicity in the effluent. Additionally, closed circuit operation with low HRT contributed to enhancing selected PPCP mass accumulation on electrodes by electro-adsorption, and thus the higher sulfonamide ARG abundance was detected in the electrodes and effluent. Moreover, the composition of bacteria was greatly influenced by the mass accumulation of PPCPs revealed by redundancy analysis results. Procrustes analysis results further demonstrated that bacterial community contributed greatly to the ARGs profiles. Therefore, ARGs with their host bacteria revealed by network analysis were partially deposited on electrode substrates, and thus ARGs were effectively accumulated on electrodes. Function analysis of the bacterial community from PICRUSt predicted metagenomes revealed that closed circuit mode enhanced the abundances of the function genes of metabolic and the multiple ARGs, suggesting that closed circuit operation exhibited positive effects on metabolic process and ARG accumulation in CW-MFC system.

The effect of the intermediate fluid-flow rate on the system performance in the closed circuit applications of the solar collector

Solar collector water heating system use solar thermal energy to provide hot water for domestic and industrial use. These systems are operated either as open-loop or closed-loop flow circuit. The former loop systems are not recommended for the cold climates having water freezing problem. Although previous studies on solar collectors have used closed-loop operation with water as the working fluid. However, it must have high boiling and low freezing points for the colder regions and thus arises the need for antifreeze mixtures of water. Another solution the same problem is the use of heat transfer oil as intermediate working fluids. In the present study, the energy and exergy analysis of a boiler supported vacuum tube solar collector system working with closed-loop in different working fluid-flow rates have been performed and evaluated. Heat transfer oil has been used as an intermediate working fluid in the closed loop system at different flow rates of 0.277 kg/s, 0.383 kg/s, and 0.494 kg/s. The results show that the collector temperature difference as well as the outlet temperature decrease. However, the collector inlet temperature increases by increasing the flow rate. Moreover, with the increase in flow rate, it was ascertained that the energy and exergy efficiency of the system and the collectors increase. The main finding of the present study is that the intermediate fluid used in the closed-circuit operation of the solar collectors has a direct effect on the energy and exergy efficiency of the system

Performance of pilot-scale horizontal subsurface flow constructed wetland coupled with a microbial fuel cell for treating wastewater

This work presents a new hybrid technology for treating wastewater along with electricity generation. The main objective of this work was to integrate a microbial fuel cell (MFC) into a horizontal subsurface constructed wetland (HSSF-CW-MFC) at a pilot scale for improving the wastewater treatment performance of HSSF-CW. The HSSF-CW-MFC was tested on three different organic loading rates: 0.15, 0.30, and 0.52 kg COD/m3/d at a set hydraulic retention time. The HSSF-CW-MFC was further studied for establishing the influence of electron transfer using conductive material (artificial electron acceptor) on wastewater treatment performance. During the efficient electron transfer (system run in closed-circuit operation), 33.7% higher chemical oxygen demand (COD) removal was achieved in comparison to the hindered electron transfer (system run in open circuit) condition. The results illustrate that efficient electron transfer from bottom anaerobic zones to the aerobic zone of the HSSF-CW helps in enhancing the treatment performance. The maximum power and current densities achieved were 11.67 mW/m3and 17.15 mA/m3, respectively.

Enhanced degradation of bisphenol A and ibuprofen by an up-flow microbial fuel cell-coupled constructed wetland and analysis of bacterial community structure

This study aims to demonstrate that an up-flow microbial fuel cell-coupled constructed wetland (UCW-MFC) can effectively treat synthetic wastewater that contains a high concentration of pharmaceutical and personal care products (PPCPs, 10 mg L−1 level), such as ibuprofen (IBP) and bisphenol A (BPA). A significant decline in chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N) removal was observed when BPA was added, which indicated that BPA was more toxic to bacteria. The closed circuit operation of UCW-MFC performed better than the open circuit mode for COD and NH4+-N removal. Similarly, the removal rates of IBP and BPA were increased by 9.3% and 18%, respectively, compared with the open circuit mode. The majority of PPCPs were removed from the bottom and anode layer, which accounted for 63.2–78.7% of the total removal. The main degradation products were identified. The removal rates of IBP and BPA decreased by 14.6% and 23.7% due to a reduction in the hydraulic detention times (HRTs) from 16 h to 4 h, respectively. Electricity generation performance, including voltage and maximum power density, initially increased and then declined with a decrease in the HRT. Additionally, both the current circuit operation mode and the HRT have an impact on the bacterial community diversity of the anode according to the results of high-throughput sequencing. The possible bacterial groups involved in PPCP degradation were identified. In summary, UCW-MFC is suitable for enabling the simultaneous removal of IBP and BPA and successful electricity production.

Influence of the Cathode Platinum Loading and of the Implementation of Membranes on the Performance of Air-Breathing Microbial Fuel Cells

The use of catalysts and membranes in microbial fuel cells (MFCs) is rather controversial. Platinum is the best catalyst to improve the oxygen reduction reaction and the implementation of an ion exchange membrane may help to avoid the oxygen leakages from the cathode to the anode compartments and, therefore, the losses of efficiencies associated to the use of oxygen by microorganisms as the immediate electron acceptor. In this work, it is studied the influence of the platinum loading in the cathode and the implementation of membrane on the performance of an air-breathing MFC. To do this, four cells were operated for 50 days in order to clarify the effect of the platinum loading contained in the cathode (0.25, 0.50, 1.00, and 2.00 mg Pt cm−2) and two additional MFCs for more than 100 days in order to evaluate the effect of the membrane on the performance of the MFC. The results obtained point out that the performance of the MFC, in terms of maximum current density and power density from the polarization curves, depends strongly on the Pt content of the cathode. This indicates that under open-circuit conditions the cathode controls the performance. Nonetheless, during the closed-circuit operation (under 120 Ω resistance), the performance is not cathodically limited as there are no significant changes between the four cells. This suggests that the performance of the MFC is limited by the anodic process. Likewise, the separation of the anode and cathode by a membrane attains a faster stabilization of the MFC and a slight improvement in the production of electricity, although for air-breathing MFC, this element does not seem to be as crucial as for other types of MFCs.

Microbial mediated desalination for ground water softening with simultaneous power generation

A novel three-chambered microbial desalination cell (MDC) was designed for evaluating desalination of synthetic ground water with simultaneous energy generation and resource recovery. The specific design enabled efficient interelectrode communication by reducing the distance of separation and also maintained an appropriate surface area to volume ratio. MDC were evaluated in different circuitry modes (open and closed) to assess the desalination efficiency, bioelectricity generation, resource recovery, substrate utilization and bioelectrokinetics. The closed circuit operation has showed efficient desalination efficiency (51.5%) and substrate utilization (70%). Owing to the effective electron transfer kinetics, closed circuit mode of operation showed effective desalination of the synthetic ground water with simultaneous power production (0.35W/m2). Circuitry specific biocatalyst activity was observed with higher peak currents (10.1mA; −5.98mA) in closed circuit mode. MDC can function as sustainable and alternative solution for ground and surface water treatment with power productivity and resource recovery.

Assessing potential cathodes for resource recovery through wastewater treatment and salinity removal using non-buffered microbial electrochemical systems

The present study evaluates relative functioning of microbial electrochemical systems (MES) for simultaneous wastewater treatment, desalination and resource recovery. Two MES were designed having abiotic cathode (MES-A) and algal biocathode (MES-B) which were investigated with synthetic feed and saline water as proxy of typical real-field wastewater. Comparative anodic and cathodic efficiencies revealed a distinct disparity in both the MES when operated in open circuit (OC) and closed circuit (CC). The maximum open circuit voltage (OCV) read in MES-A and MES-B was about 700mV and 600mV, respectively. Salinity and organic carbon removal efficiencies were noticed high during CC operation as 72% and 55% in MES-A and 60% and 63% in MES-B. These discrete observations evidenced ascribe to the influence of microbial electrochemical induced ion-migration over cathodic reduction reactions (CRR).