Samar Amari, Mohammad Boshrouyeh Ghandashtani

Water and Environment Journal • 2019

Abstract The two‐chambered microbial fuel cell (MFC) was designed and used for studying the efficiency of the real wastewater treatment from a non‐steroidal anti‐inflammatory pharmaceutical plant as well as from synthetic wastewater containing diclofenac sodium (DS). The removal of the contaminants was expressed regarding chemical oxygen demand (COD) removal, as measured by spectrophotometry experiments. Moreover, the effect of two different types of the cathode on current characteristics and COD removal was investigated. This research showed that the Pt‐coated Ti cathode could lead to higher efficiency of both power density and COD removal. In this case, the results indicated that the maximum power density ( P max ) was 20.5 and 6.5 W/m 3 and the maximum COD removal was 93 and 78% for MFCs using real and synthetic wastewater, respectively.

Mojeed Opeyemi Oyedeji, Abdullah Alharbi, Mujahed Aldhaifallah et al.

Energies • 2023

Microbial fuel cells (MFCs) are biocells that use microorganisms as biocatalysts to break down organic matter and convert chemical energy into electrical energy. Presently, the application of MFCs as alternative energy sources is limited by their low power attribute. Optimization of MFCs is very important to harness optimum energy. In this study, we develop optimal data-driven models for a typical MFC synthesized from polymethylmethacrylate and two graphite plates using machine learning algorithms including support vector regression (SVR), artificial neural networks (ANNs), Gaussian process regression (GPR), and ensemble learners. Power density and output voltage were modeled from two different datasets; the first dataset has current density and anolyte concentration as features, while the second dataset considers current density and chemical oxygen demand as features. Hyperparameter optimization was carried out on each of the considered machine learning-based models using Bayesian optimization, grid search, and random search to arrive at the best possible models for the MFC. A model was derived for power density and output voltage having 99% accuracy on testing set evaluations.

Thabed Tholib Baladraf

ECS Meeting Abstracts • 2021

The increase in world population is in line with the increase in the amount of energy demand, especially electricity. However, the energy used today is still using fossil energy, which one day will run out. Dependence on non-renewable energy causes weak energy resistance, resulting in electricity scarcity. Microbial fuel cells (MFC) can be a new alternative energy source because they can generate electrical energy by utilizing the interactions of bacteria found in nature. To fulfill electricity needs, researchers created a tool that can generate electrical energy by utilizing food waste and human waste as a substrate which is converted into electrical energy through the bioelectrochemical activity of electrons and protons by bacteria. The tool is integrated with the internet of things as an effort to use technology so that it can control temperature and voltage automatically. This research was aimed to determine the design of a tool to convert food waste and human waste into clean renewable electrical energy, determine the working principle of the tool, determine the efficiency of the tool in producing electrical energy, and determine the potential of the tool to meet electricity needs. The research was carried out using 3 variations, namely variation 1 (zinc and cathode), variation 2 (food waste, human waste, and water), variation 3 (carbon, cathode, nutrient broth, electrolyte solution, food waste, and human waste). The tool created is portable with a DC voltage of 12 V to AC 220 V 500 W and the best results are obtained from variation 3 with 26.6 volts from 1.8 liters of food waste and human waste to obtain a voltage efficiency of up to 95%. This tool has the potential to overcome the electrical energy crisis and fulfill people's electricity needs by utilizing food waste and human waste.

Alfredo Costilla Reyes, Celal Erbay, Salvador Carreon-Bautista et al.

Applied Sciences • 2018

Microbial Fuel Cell (MFC) technology is a novel Energy Harvesting (EH) source that can transform organic substrates in wastewater into electricity through a bioelectrochemical process. However, its limited output power available per liter is in the range of a few milliwatts, which results very limited to be used by an Internet of Things (IoT) smart node that could require power in the order of hundreds of milliwatts when in full operation. One way to reach a usable power output is to connect several MFCs in series or parallel; nevertheless, the high output characteristic resistance of MFCs and differences in output voltage from multiple MFCs, dramatically worsens its power efficiency for both series and parallel arrangements. In this paper, a Power Management System (PMS) is proposed to allow maximum power harvesting from multiple MFCs while providing a regulated output voltage. To enable a more efficient and reliable power-harvesting process from multiple MFCs that considers the biochemical limitations of the bacteria to extend its lifetime, a power ranking and MFC health-protection algorithm using an interleaved EH operation was implemented in a PIC24F16KA102 microcontroller. A power extraction sub-block of the system includes an ultra-low-power BQ25505 step-up DC-DC converter, which integrates Maximum Power Point Tracking (MPPT) capabilities. The maximum efficiency measured of the PMS was ~50.7%. The energy harvesting technique presented in this work was tested to power an internet-enabled temperature-sensing smart node.

Emut Sukma Sejati, Sudarlin

Journal of Physics: Conference Series • 2021

Abstract Ceramic is low-cost separator membrane has widely applied in dual-chambered Microbial Fuel Cell (MFC). Its big pores and other chemical and physical advantages make it suitable to substitute expensive exchange separator membranes. The purpose of this study is to enhance electricity of ceramic-based microbial fuel cell by using various number of carbon electrode pairs. This study uses tempe waste as anolyte and KMnO4 as its catholyte to gain electricity. Three variety of electrode pairs data of electricity result is processed statistically to examine significant difference of voltage, current, and power density as parameters. The result of this study shows that electricity of three-electrode pairs has a higher average of power density with the number 1447,91 mW/m 2 , the difference between three and two electrode pairs is around 588 mW/m 2 and between three and one electrode pairs is 910 mW/m 2 . It has significant difference between one, two, and three-electrode pairs in the parameters.

Yang-Guo Zhao, Yanhui Zhao, Yi Zhang et al.

Water Science and Technology • 2018

Abstract Thermophile pretreatment of activated sludge greatly improves the biodegradability of sludge, but whether the pretreated products are suitable for the electricity generation of microbial fuel cells (MFCs) is still little known. In this study, municipal activated sludge pretreated by a thermophilic bacterium and heating, respectively, was separately fed into the MFCs. The performance of MFCs was examined and changes of anodic microbial communities were investigated with scanning electron microscopy and 16S rRNA gene high-throughput sequencing on the Illumina Miseq platform. The results showed that MFCs fed with heating-pretreated sludge performed preferably and the power density reached 0.91–2.86 W/m3. MFC anodes were covered with considerable Geobacter spp. However, the bioaugmentation of sludge with the thermophile was not able to support a high potential output although the pretreatment significantly increased the soluble chemical oxygen demand. The maximum power density approached 0.20 W/m3 even when the anolyte was regularly changed. It was observed that amending pH did not improve the performance of MFC. Investigation on this anodic microbial community found that the relative abundance of Lactobacillus spp. exceeded 91%. Consequently, the thermophile-pretreated products stimulated the growth of non-exoelectrogens and finally the niches of anodic biofilm were completely occupied by Lactobacillus spp.

Pranabendu Mitra, Gordon A. Hill

The Canadian Journal of Chemical Engineering • 2011

Abstract A complete microbial fuel cell (MFC) operating under continuous flow conditions and using Chlorella vulgaris at the cathode and Saccharomyces cerevisiae at the anode was investigated for the production of electricity. The MFC was loaded with different resistances to characterise its power capabilities and voltage dynamics. A cell recycle system was also introduced to the cathode to observe the effect of microalgae cell density on steady‐state power production and dynamic voltage profiles. At the maximum microalgae cell density of 2140 mg/L, a maximum power level of 0.6 mW/m 2 of electrode surface area was achieved. The voltage difference between the cathode and anode decreased as the resistance decreased within the closed circuit, with a maximum open circuit voltage (infinite resistance) of 220 mV. The highest current flow of 1.0 mA/m 2 of electrode surface area was achieved at an applied resistance of 250 Ω.

Bustami Ibrahim, Uju Uju, Alvindo Chrisna Mukti

Jurnal Pengolahan Hasil Perikanan Indonesia • 2019

Microbial fuel cell (MFC) is a bioreactor utilizing bacteria as electrocatalysts to convert bioenergy from biomass into electrical energy. The aim of this research were to determine the effects of the electrode distance on the bacterial density and the electrical value generated by the MFC as well as to evaluate the ability of MFC in reducing the pollutant. Single chamber MFC system with various electrode distances including 2 cm, 4 cm, and 6 cm were assembled. The wastewater of fish pindang processing was used as the medium<br />for the MFC. The results showed that the distance had no effect on the biofilm density of the electrode and the reduction of the wastewater pollutant load. However, the distance affected the electrical value of the<br />MFC. Biofilm density on the MFC electrode after 120 hours was 0.65-6.46 CFU/ cm2. The highest voltage was obtained from the 6 cm electrode distance with the voltage 0.38±0.01 V. Positive correlation (R2 = 0.99)<br />between microbial density and electricity produced at the cathode was observed, but weak at the anoda (R2 = 0.47). The MFC system could decrease the BOD value up to 50.78% and COD up to 33.29%, however the TAN value was increased to 6 mg/L.

Xiaoye Xing, Zhongliang Liu, Wenwen Chen et al.

Catalysts • 2020

Dandelion seeds (DSs) have the advantages of high nitrogen content, low cost and easy availability and thus are ideal carbon precursors for fabricating carbon nanomaterials. Herein, this paper prepared a carbon nanosheet material by one-step carbonizing DSs with KOH activation (self-doped-nitrogen porous carbon nanosheets (N-CNS)) and without KOH activation (unactivated self-doped-nitrogen porous carbon nanosheets (N-UA-CNS)), which could dope nitrogen atoms directly into carbon materials without additional processes. Scanning electron microscopy(SEM) images and X-ray diffraction(XRD) patterns both showed that N-CNS was of macro-porous structure, and beneficial for microorganisms’ growth. The Brunauer Emmett Teller(BET) surface area of N-CNS was 2107.5 m2 g−1, which was much higher than that of N-UA-CNS. After carbon clothes were modified by the obtained materials, the internal resistance of both N-CNS-modified carbon cloth (N-CNS-CC) and N-UA-CNS-modified carbon cloth (N-UA-CNS-CC) was greatly reduced and was found to be only 2.7 Ω and 4.0 Ω, respectively which are all significantly smaller than that of blank carbon cloth (65.1 Ω). These electrodes were assembled in microbial fuel cells (MFCs) as anode, and the operation experiments showed that the N-CNS modification shortened start-up time, improved output stability and increased maximum output voltage significantly. The maximum power density of N-CNS-CC MFC was 1122.41 mW m−2 which was 1.3 times of that of N-UA-CNS-CC MFC and 1.6 times of that of CC MFC. The results demonstrated that N-CNS was an ideal modification material for fabricating MFC anodes with simple preparation process and low cost.

Junxian Shi, Anhuai Lu, Haibin Chu et al.

Applied Sciences • 2018

Developing simple and cheap electrocatalysts or photocatalysts for cathodes to increase the oxygen reduction process is a key factor for better utilization of microbial fuel cells (MFCs). Here, we report the investigation of natural wolframite employed as a low-cost cathode photocatalyst to improve the performance of MFCs. The semiconducting wolframite was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. The band gap and photo respond activities were determined by UV-vis spectroscopy and linear sweep voltammetry (LSV), respectively. Compared with the normal graphite cathode, when MFCs were equipped with a wolframite-coated cathode, the maximum power density was increased from 41.47 mW·m−2 to 95.51 mW·m−2. Notably, the maximum power density further improved to 135.57 mW·m−2 under light irradiation, which was 2.4 times higher than with a graphite cathode. Our research demonstrated that natural wolframite, a low-cost and abundant natural semiconducting mineral, showed promise as an effective photocathode catalyst which has great potential applications related to utilizing natural minerals in MFCs and for environmental remediation by MFCs in the future.

Silvia Wessel, Shanna Knights, Mike Lauritzen et al.

ECS Meeting Abstracts • 2014

Over the past 30 years Ballard’s PEM fuel technology evolved from proof-of-concept single cells via sub-scale and full-scale prototype systems to products in the areas of motive power (buses and materials handling), back-up power, co-generation, and distributed power generation which have been deployed extensively in demonstration programs and field trails. Today, Ballard is a leader in fuel cell stack design and manufacturing with products being commercially deployed in the materials handing and back-up power markets which both benefit from attractive financial value propositions. Furthermore, extensive research and development is also focused on bus stack and large scale distributed generation technology. In early technology demonstrations and field trials specifically in the transportation sector fuel cell performance was the key attribute under consideration; however, today the emphasis is on durability and cost which are the two major challenges that still hinder large-scale commercialization of fuel cell technology across all markets. Since 1991 Ballard’s fuel cell bus technology has been deployed in a variety of demonstration projects and today 49 fuel cell buses are in operation worldwide. The largest bus fleet deployed in 2009 in Whistler, B.C. has accumulated more than 150,000 hours of operational hours and a total driving distance of >3 million kilometers. The figure on the right shows the average cell performance of the buses which exceeds the warranted operational life of 8000 hours of the HD6 stack. As opportunities in the fuel cell bus market have accelerated over the last decade and with the development of over six generations of fuel cell modules, Ballard has overcome technical barriers related to power density and reliability. To date, the bus transportation platform developed by Ballard has been proven to meet the demands of range and duty cycle expectations, but the key barriers pertaining to cost and durability under the wide range of operating conditions necessary for transportation fuel cell stacks still remain. Ballard’s overall activities on reducing product cost have been driven by several approaches; (1) product design improvements that include reduced platinum loadings, lower part counts, and enhanced durability, (2) reduced sourcing costs through lower materials costs and increased volumes, (3) increased manufacturing efficiencies including use of continuous, automated assembly, (4) production scale up through increased market penetration. Since 2003 Ballard has achieved substantial cost reductions while increasing stack operational life 4-fold. Ballard’s large numbers of demonstration programs and field trials have been instrumental in providing insight into stack and MEA failure modes and this understandingtogether with modeling and fundamental research has been a driver in durability improvement through MEA design opportunities and operational mitigation strategies. The work that will be presented will provide an overview of Ballard’s Fuel Cell bus program, discuss the different aspects of stack durability that has been achieved over the last 10 years, and provide an insight into current research and development that is needed to narrow the durability and cost gap for large-scale commercialization.

Gaixiu Yang, Dong Chen, Pengmei Lv et al.

Scientific Reports • 2016

Abstract Bimetallic nanoparticles with core-shell structures usually display enhanced catalytic properties due to the lattice strain created between the core and shell regions. In this study, we demonstrate the application of bimetallic Au-Pd nanoparticles with an Au core and a thin Pd shell as cathode catalysts in microbial fuel cells, which represent a promising technology for wastewater treatment, while directly generating electrical energy. In specific, in comparison with the hollow structured Pt nanoparticles, a benchmark for the electrocatalysis, the bimetallic core-shell Au-Pd nanoparticles are found to have superior activity and stability for oxygen reduction reaction in a neutral condition due to the strong electronic interaction and lattice strain effect between the Au core and the Pd shell domains. The maximum power density generated in a membraneless single-chamber microbial fuel cell running on wastewater with core-shell Au-Pd as cathode catalysts is ca. 16.0 W m −3 and remains stable over 150 days, clearly illustrating the potential of core-shell nanostructures in the applications of microbial fuel cells.

Kumar Pijush Kataky, Amaresh Dalal, Gautam Biswas et al.

IOP Conference Series: Earth and Environmental Science • 2020

Abstract Microbial Fuel Cell (MFC) has various application potential as in generation of bioelectricity, bio-hydrogen production, waste water treatment and it is also used as biosensors. It would not be possible to headway without mentioning that MFCs have quite a many similarities with Chemical Fuel Cells (CFC). It is seen that a lot of research is carried out for CFCs as compared to MFCs. Most of the research works on MFCs include experimental approach while very few computational studies have been carried out for MFCs. So an endeavour is made to create a model which mimics the working by simulating the key physical and biochemical processes occurring. Results imply that variation of current density occurs with change in Reynolds number (Re) and kinetic rate of reaction (k) which lead to the study of effects of variation of flow rates, turbulence and the action of different bacteria in the efficiency of MFCs. The current density achieved computationally is around 512 mA/m 2 for Re=5 and k=10 −3 which is in good agreement with the experimental data. Regions of higher current density are found which can be used to improvise the MFCs. Present mathematical model provides a new perspective in understanding the biomass concentration across the MFC and gives better knowledge of the mechanisms taking place. This simple computational framework provides insight into the fluid dynamics involved during continuous feeding, by overcoming the limitations and technical barriers in monitoring and examining through experiments. By implementing the findings from this model optimization of designs can be achieved leading to higher current generation, increase in efficacy and cost effective production techniques which paves the way for future work.

Uttam Ghosh, Rahul Gautam, Jagdeep Nayak

Global NEST International Conference on Environmental Science & Technology • 2022

Microbial Fuel Cell (MFC) technology is based on bioelectrochemical system, extract power from organic load of the wastes to produce bio-electricity. The present study have evaluated the effect of the different electrode materials in two sets of mediator-less H- type double chambered MFC operated at 30 ± 2 °C in a batch mode. In MFCGG, graphite rods (G) and in MFCCBG carbon brush (CB) and graphite rod (G) were used as anode and cathode electrode respectively. The both MFC were fed with distillery spent wash as a substrate with HRT of 21 days. The maximum COD removal of 61.07 % and 67.17 %; open circuit voltage (OCV) of 565 and 735 mV were achieved in MFCGG and MFCCBG respectively. The peak power densities of 3.19 W/m2 and 5.4 W/m2 were recorded in MFCGG and MFCCBG. These results suggest the efficacy of carbon brush anode in MFCCBG compared to graphite rod as an anode material in MFC for bioelectricity production.

Prapti Ira Kumalasari, Junety Monde, Zefanya Bernadi Yusuf et al.

CHEESA: Chemical Engineering Research Articles • 2019

<p class="PageNumber1">Kalimantan merupakan pulau yang terkenal akan sektor pertambangan salah satunya di daerah delta Mahakam, yang dalam proses eksploitasinya berpotensi menghasilkan limbah logam berat, seperti logam berat Cr<sup>6+</sup>. Pencemaran logam Cr<sup>6+</sup> cukup sulit untuk terurai dilingkungan dan bersifat karsinogenik, karena dengan konsentrasi kecil saja dapat menimbulkan tingkat keracunan yang sangat tinggi pada makhluk hidup, sehingga pengolahan terhadap limbah tersebut sangat penting. <em>Microbial Fuel Cell</em> merupakan suatu metode yang dapat membantu proses pengolahan limbah dengan cara mereduksi Cr<sup>6+</sup> menjadi Cr<sup>3+</sup> dengan katalisis mikrobiologis. Penelitian ini menggunakan metode reaktor <em>double-chamber</em> yaitu terdapat ruang anoda yang berisi bakteri anaerob dan <em>basic anolyte</em>, sedangkan pada ruang katoda terdapat kalium dikromat dengan konsentrasi 18 mg/L dan variasi pH 3, 4 dan 5 yang dilakukan selama 10 hari. Kondisi pH optimum pada proses reduksi terjadi pada pH 4 dengan besar persen penurunan sekitar 98%. Dan produksi listrik tertinggi pada hari ke-2 pada variasi pH 3 dengan nilai power density sebesar sebesar 11, 06 mW/m<sup>2</sup>.</p>

Shalini Prajapati, Pydi Setty Yelamarthi

Asia-Pacific Journal of Chemical Engineering • 2020

Abstract Microbial fuel cell (MFC) is a promising technology for wastewater treatment coupled with electricity generation. Biowaste‐derived electrodes are used to improve the surface area, roughness, and hydrophilicity, which play pivotal role in the enhanced biofilm formation. In the present study, Ficus religiosa leaves (FRL) biowaste was used to develop the bioelectrode. In this study, Congo red (CR) dye decolorization was performed using MFC, wherein the effect of dye decolorization with respect to dye concentration, glucose concentration, and hydraulic retention time (HRT) was studied. The surface roughness and distribution of carbon powder on carbon cloth were confirmed using scanning electron microscope (SEM) analysis. Also, Bacillus subtilis adhesion and chain‐like structure formation on the electrode confirmed the biofilm formation on the electrode. The polarization curve was performed to assess the MFC performance. The maximum power density of 70.50 mW/m 2 and current density of 251.79 mA/m 2 at 2,224 Ω was achieved. The maximum decolorization of 80.95 ± 2.08% and COD reduction of 73.96 ± 1.76% were obtained, respectively, after complete treatment of MFC for 54 h. UV‐visible spectrometry analysis of dye contained samples during MFC treatment at various time intervals was confirmed the cleavage of azo bond (NN), and the corresponding peak intensity variation was noticed at 490 nm.

Wenguo Wu, Huiya Hong, Jia Lin et al.

Biosensors • 2024

Simultaneous monitoring of antimicrobial responses to bacterial metabolic activity and biofilm formation is critical for efficient screening of new anti-biofilm drugs. A microbial fuel cell-based biosensor using Pseudomonas aeruginosa as an electricigen was constructed. The effects of silver nanoparticles (AgNPs) on the cellular metabolic activity and biofilm formation of P. aeruginosa in the biosensors were investigated and compared with the traditional biofilm detection method. The crystal violet staining results showed that the concentration of AgNPs being increased to 20 and 40 μg/mL had a slight and obvious inhibitory effect on biofilm formation, respectively. In comparison, the detection sensitivity of the biosensor was much higher. When the concentration of AgNPs was 5 μg/mL, the output voltage of the biosensor was suppressed, and the inhibition gradually increased with the AgNPs dose. AgNPs inhibited the activity of planktonic cells in the anolyte and the formation of biofilm on the anode surface, and it had a dose-dependent effect on the secretion of phenazine in the anolyte. The biosensor could monitor the impacts of AgNPs not only on biofilm formation but also on cell activity and metabolic activity. It provides a new and sensitive method for the screening of anti-biofilm drugs.

Bustami Ibrahim, Pipih Suptijah, Bagus Sukma Agung

Jurnal Pengolahan Hasil Perikanan Indonesia • 2017

Microbial fuel cell (MFC) is a technology that can produce electricity with helping exoelectrogenic<br />bacteria. The technology can also utilize fishery processing wastewater as a media for bacteria to live, so<br />it can reduce organic pollution load in the wastewater. Purpose of this research was to identify the effect<br />of electrodes distance to electricity and water quality parameters of fisheries processing wastewater using<br />MFC technology.. The MFC system used was single chamber system. The distance between electrodes used<br />were 2 cm, 4 cm and 6 cm and the electrodes were made of stainless wire mesh coated with chitosan and<br />active carbon. The results showed that electrodes distance affected to MFC electricity within salted boiled<br />fish wastewater media. The average value of electric current during 48 hours observation on the distance<br />of 2 cm, 4 cm and 6 cm were 0.17±0.06 mA, 0.46±0.17 mA and 0.44±0.16 mA, respectively. Average values<br />of electric voltage on the distance of 2 cm, 4 cm and 6 cm were 0.12±0.03 V, 0.34±0.07 V and 0.37±0.08 V,<br />respectively. The research also showed that MFC system can decrease average value of BOD 20.5%, COD<br />30.41%, and TAN 21.2 % of salted boiled fish wastewater media.<br /><br />

Jon Chouler, Mirella Di Lorenzo

Water Science and Technology • 2019

Abstract Microbial fuel cell (MFC) technology holds enormous potential for inexpensive real-time and onsite testing of water sources. With the intent of defining optimal operational conditions, we investigated the effect of environmental factors (changes in temperature, pH and ionic strength), on the performance of a single chamber miniature MFC sensor. The pH of the influent had the greatest effect on the MFC performance, with a 0.531 ± 0.064 μA cm−2 current variation per unit change of pH. Within the range tested, temperature and ionic strength had only a minor impact (0.010 ± 0.001 μA °C−1 cm−2 and of 0.027 ± 0.003 μA mS−1 cm cm−2 respectively). Under controlled operational conditions, for the first time, we demonstrated the ability of this biosensor to detect one of the most commonly applied pesticides worldwide, atrazine. The sensitivity to atrazine was 1.39 ± 0.26 ppm−1 cm−2, with a detection range of 0.05–0.3 ppm. Guidelines for systematic studies of MFC biosensors for practical applications through a factorial design approach are also provided. Consequently, our work not only enforces the promise of miniature MFC biosensors for organic pollutants detection in waters, but it also provides important directions towards future investigations for infield applications.

Tensay Kifle, Esayas Alemayehu, Chali Dereje Kitila

Environmental Health Engineering and Management • 2023

Background: The energy crisis is a growing problem around the world, requiring the creation of alternative energy sources that can generate less carbon dioxide and benefit the ecosystem. Reutilization of wastewater is becoming the emerging energy solution. Wastewater contains a large amount of organic matter that can be oxidized in microbial fuel cells (MFCs) to produce electricity. MFCs use biodegradable materials to create energy in the presence of microorganisms. Methods: Purposive sampling technique was employed to collect samples from critical polluting sources. The samples were certainly maintained in a refrigerator at 4°C. Several mixes for sample were prepared and tested analytically- for physio-chemical and bacteriological characterizations of each substrate status at pre- and post-treatment stages. Electricity generating capacity of MFCs that employing different substrates was investigated experimentally using batch reactors. The cross-sectional methodology was employed to study possible power generation. Results: The maximum voltage output of 118.93, 144.84, and 89.76 mV were produced keeping the resistance unlimited for MFC1 (urine substrate), MFC2 (blackwater substrate), and MFC3 (graywater substrate), respectively. MFC that utilized graywater as a substrate brought the tiniest quantity of electricity; however, it stood the most stable. The highest COD reduction (65.83%) in the process was reported in urine substrate and the highest BOD5 removal (69.18%) was reported in black water substrate. Conclusion: The experimental results provided a promising indication of MFCs viability, providing hope for future power generation and alternative wastewater treatment option in developing countries.

Diana Marcela Vanegas-Hernández, Mónica Liliana Cardona-Aristizabal, Zulamita Zapata-Benabithe

Revista Facultad de Ingeniería • 2020

In this work, three types of activated carbons were evaluated as electrodes in the anode chamber of a two-chamber microbial fuel cell (MFC). The evaluation was applied using a pure Shewanella Putrefaciens culture due to its gram-negative characteristics. In the cathode chamber, a platinum electrode was used, and a Nafion® 117 proton exchange membrane was selected as a separator of both chambers. The activated carbons were obtained from different precursors (coffee husk, commercial coal, and mineral coal), with different microporous and surface properties. From the voltage and current measurements, it was found that the cell power values varied between 0.008 mW and 0.045 mW. The electrode obtained from chemical activation of coffee husk with H3PO4 at 450 °C (Q) showed the best electrochemical behaviour and highest power values. This result may be mainly related to the macroscopic morphology and mesopores that improve the wettability of the surface by the medium thought carbonaceous material. SEM images showed a better biofilm formation, larger filaments of the bacteria, and micro-beds formation over the surface of bio-anode Q, which improved the interaction with the microorganism, its metabolism, and electrons extracellular transfer. Therefore, activated carbon from coffee husk could be considered as a promising material for electrodes of microbial fuel cells.

Seonyeob Kim, Agha Raza Abid, Jae Jun Jang et al.

Journal of Fuel Cell Science and Technology • 2013

A new hybrid system of molten carbonate fuel cell (MCFC) and homogenous charge compression ignition (HCCI) engine is suggested to improve the overall system efficiency and performance. In the proposed system, the catalytic burner in a standalone MCFC system is replaced with the HCCI engine. The HCCI engine is chosen over conventional spark-ignition or compression-ignition engines since it has been demonstrated to operate with highly diluted reactant mixture, which is suitable to run directly with the MCFC anode off-gas. A nonisothermal numerical model that incorporates major fuel cell losses is developed to predict the fuel cell performance. The fuel cell model assumes parallel anode and cathode flow configuration with LiNaCO3 as an electrolyte. It is integrated with an in-house HCCI engine model to investigate the hybrid system performance. At the selected design point operation around 300 kW power output, the maximum hybrid system efficiency is 21.2% (relative) higher than that of a standalone fuel cell system and, thus, achieving around 60% overall, which demonstrates the potential of the suggested hybrid system as a highly-efficient distributed power generation source in the near future.

P. Gazdzicki, J. Mitzel, A. M. Dreizler et al.

Fuel Cells • 2017

Abstract The paper focuses on the investigation of durability and performance of a low temperature polymer electrolyte membrane fuel cell (PEMFC) stack as a function of Pt loading in automotive test conditions. Major motivations are problems related to the need to reduce the amount of Pt in membrane electrode assemblies (MEAs) in order to make PEMFC more competitive. The particular challenge is to maintain sufficiently high performance and long‐term durability. The study shows that for cathode Pt loadings below 0.2 mg cm −2 and for current densities exceeding 1 A cm −2 a sudden drop of performance is observed. The same threshold value is found for the increase of irreversible voltage losses which lead to an intense reduction of PEMFC durability for cathodic loadings below 0.2 mg cm −2 . Another durability issue at cathodic Pt loadings < 0.4 mg cm −2 is the acceleration of reversible degradation, which leads to a strong voltage drop during continues fuel cell operation (i.e., without a recovery interruption).

Antonia Jimenez Rodrí­guez, Antonio Serrano, Teresa Benjumea et al.

Emerging Science Journal • 2019

The bioelectrochemical systems are a sustainable technology that can be used to obtain electricity and/or reduced compounds. However, this novel technology presents several challenges prior to its implementation at full-scale. The aim of the present study was to evaluate different nanomaterials of electrode and mediators to increase the performance of BioElectrochemical Systems production. In order to achieve this objective, it was compared the use of Multiwall Carbon Nanotubes and Multiwall Carbon Nanotubes plus electron exogenous mediator (Meldola's Blue) against plain graphite anode in order to evaluate the overall start-up time and other electro-chemical features. The use of multi-walled carbon nanotubes reduces substantially (by 75%) the start-up time required in a microbial fuel cell to produce stable voltage both, with and without the use of mediator compare to the plain anode. This reduction of the required time can be a consequence of the formation of anodic binders between this compound and the bacteria. With the independence of the start-up time, the current production was similar in the three studied cases, about 650 mV. Use of nanotubes modified anode surfaces might be especially interesting in cases of recovery after unstable operation of a microbial fuel cell, and/or reducing the start-up time for the generation of energy from new systems.

I. S. Michie, J. R. Kim, R. M. Dinsdale et al.

Water Science and Technology • 2013

For the successful scale-up of microbial fuel cell (MFC) systems, enrichment strategies are required that not only maximise reactor performance but also allow anodic biofilms to be robust to environmental change. Cluster analysis of Denaturing Gradient Gel Electrophoresis community fingerprints showed that anodic biofilms were enriched according to substrate type and temperature. Acetate produced the highest power density of 7.2 W m−3 and butyrate the lowest at 0.29 W m−3, but it was also found that the trophic conditions used to acclimate the electrogenic biofilms also determined the MFC response to different substrate types, with both acetate and butyrate substrates recording power densities of 1.07 and 1.0 W m−3 respectively in a sucrose enriched reactor. When temperature perturbations were introduced to investigate the stability of the different substrate acclimated electrogenic biofilms, the 20 °C acclimated acetate reactor was unaffected by 10 °C operation but all reactors acclimated at 35 °C were adversely affected. When the operating temperature was raised back to 35 °C both the acetate and butyrate reactors recovered electrogenic activity but the sucrose reactor did not. It is thought that this was due to the more complex syntropic interactions that are required to occur when metabolising more complex substrate types.

Khair Un Nisa, Williane da Silva Freitas, Alessandra D’Epifanio et al.

Catalysts • 2024

Microbial fuel cells (MFCs) are sustainable energy recovery systems because they use organic waste as biofuel. Using critical raw materials (CRMs), like platinum-group metals, at the cathode side threatens MFC technology’s sustainability and raises costs. By developing an efficient electrode design for MFC performance enhancement, CRM-based cathodic catalysts should be replaced with CRM-free materials. This work proposes developing and optimizing iron-based air cathodes for enhancing oxygen reduction in MFCs. By subjecting iron phthalocyanine and carbon black pearls to controlled thermal treatments, we obtained Fe-based electrocatalysts combining high surface area (628 m2 g−1) and catalytic activity for O2 reduction at near-neutral pH. The electrocatalysts were integrated on carbon cloth and carbon paper to obtain gas diffusion electrodes whose architecture was optimized to maximize MFC performance. Excellent cell performance was achieved with the carbon-paper-based cathode modified with the Fe-based electrocatalysts (maximum power density-PDmax = 1028 mWm−2) compared to a traditional electrode design based on carbon cloth (619 mWm−2), indicating the optimized cathodes as promising electrodes for energy recovery in an MFC application.

Ivar Kruusenberg, Kush Chadha, Taarini Atal

ECS Meeting Abstracts • 2022

It is of utmost importance to develop light weight fuel cell stacks and find the ways to integrate these to light weight and low temperature fuel cell systems. In order to meet the future energy demands non-polluting, compact, transportation and portable applications are required. Current energy systems have lower power density (kW/kg) resulting in optimized power only at higher overall weight. Systems with higher power density demands higher initial setup costs. Low temperature PEMFC, on other hand offers various advantages but fails to provide the required output without exceeding the weight of the fuel cell stack and thereby fuel cell systems. A fuel cell system consists of a fuel cell stack, compressed gas in cylinder, pressure relief valves, regulators, water pump, sensors and cvm. A fuel cell stack is the main component consisting of one of the devices with maximum weight and cost contribution. In such case, developing a system with stack having higher power density reduces overall weight and increases power density (kW/kg). PowerUP Energy Technologies has developed light weight fuel cell stack to achieve higher power density. Experiments considering flow field designs, recirculation strategy, different anode configuration has been a subject of study. Dead-end anode, closed cathode configuration of fuel cell stack further improves fuel utilization. Recirculation line of hydrogen if further added can improve in overall fuel utilization. Counter flow arrangement for reactant distribution further removes the necessity of humidifying the gases. This result in removal of humidifiers and thereby reducing the weight of the fuel cell system in total. Portable fuel cell systems have flexibility for ease in transportation and stationery solutions. Furthermore, lighter fuel cell stacks add advantage for higher output power at lower overall weights. This stack developed is further optimized with improved flow field designs and design of manifold. These fuel cell stacks are used in PowerUP’s portable fuel cell electric generators that are more efficient and sustainable than the currently used fossil fuel based solutions.

Dinh Thi Thu Ha, Pham Ngoc Phat

Vietnam Journal of Science and Technology • 2024

The two main pollution parameters, BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand), are crucial factors in assessing water quality and pollution levels. Currently, COD can be measured using sensor devices, while BOD relies on the activity of microorganisms. Traditionally, the quantification of biologically oxidizable organic carbon involves measuring oxygen consumption over a five-day period, commonly known as the BOD5 test. However, the BOD5 test has several disadvantages, such as its time-consuming nature, unsuitability for process control, and the requirement for highly skilled samplers. It was hypothesized that the output of a single-chamber microbial fuel cell (SCMFC) with an air cathode could serve as an alternative method for measuring BOD. To validate this hypothesis, this study conducted some experiments using the model of SCMFC. When artificial wastewater, utilizing sodium acetate as fuel, was employed, a strong linear correlation (R2 > 0.99) between the total charge transferred and BOD5 concentration was confirmed. Additionally, the linear relationship was also investigated for real domestic wastewater. This relationship was also examined for real domestic wastewater, resulting in a combined correlation with an R2 value exceeding 0.98. Until now, research on biosensors (particularly SCMFC-based biosensors) in Vietnam has been relatively new and not extensively conducted. The results of this study could provide a solid foundation for the development of continuous and onsite BOD sensors to monitor BOD concentrations in wastewater streams.

Sho Tamura, Motoaki Morita, Shinichi Motoda et al.

ECS Transactions • 2014

It has been reported that the potential of stainless steel (S.S.) ennobles to 400 mV by the formation of biofilm in seawater. This phenomenon can lead to the development of a battery by coupling an active counter electrode. On the other hand, TiO 2 is well known as an n-type semiconductor which exhibits the photo-catalytic effect under the UV irradiation. When a TiO 2 coated metal is irradiated by the UV light, excited electrons are transferred to the base metal, this phenomenon leads to the active shift of electrode potential. This effect can be applied to microbial fuel cell as a non-sacrifice electrode. We have investigated the electrochemical characteristics of the marine microbial fuel cell (MMFC) composed of biofilm covered stainless steel cathode and TiO 2 anode in seawater. However, it is needed to improve the photo-potential characteristics of electrodes for the practical application.The present work attempted to improve the battery performance by assembling the double layered TiO 2 anode electrode.Results from experimental, by using the double layered anode for MFC, cell voltage increases 120 mV and maximum power density enhances 1.4 times compared with the value of single layered one coated by squeegee printing method. The double layered electrode has anatase / rutile hetero-junction, therefore it promotes the electron transfer between base metal and TiO 2 coating interface. In addition, the double layered electrode has a high durability against the cyclic irradiation because TiO 2 intermediate layer behaves as a corrosion protective barrier which suppresses the direct contact between electrolyte and base metal.

Xiao Li Wang, Chen Wu, Jia Qi Zhang et al.

Advanced Materials Research • 2010

In this paper, it has been studied the acclimation stage of a synthetic wastewater fed with glucose as a carbon source, using a tow-chambers microbial fuel cells (MFCs). Special attention has been paid to the start-up. During the acclimation period, the microbial fuel cells (MFCs) will be exposed to variations in operating parameters. Hence, the acclimation stage of MFCs, exposed to variation in the influent COD, operating temperature, and electron acceptor, was investigated in the terms of power density, COD removal efficiency, and voltage while treating a synthetic wastewater. The power density is increased and the acclimation period is prolonged with the increase of the influent COD up to meet steady-state conditions. It is important to note that the acclimation of MFCs is not only impacted by the electricity-generating bacteria, but by the whole biological. The highest steady-state voltage, which is about 404mV, is obtained at 35°C, comparing to the operating temperature of 15°C or 25°C. In addition, the electron acceptor will obviously influence the steady-state voltage and start-up period.

Ying Wang, Cui‐e Zhao, Dong Sun et al.

ChemPlusChem • 2013

Abstract A microbial fuel cell (MFC) is an innovative power‐output device, which utilizes microorganisms to metabolize fuel and transfers electrons to the electrode surface. In this study, we decorated the surface of graphene (G) with a conducting polymer, poly(3,4‐ethylenedioxythiophene) (PEDOT), through galvanostatic electropolymerization to fabricate a G/PEDOT hybrid anode for an Escherichia coli MFC. Cyclic voltammetry and electrochemical impedance spectroscopy analyses illustrated that the G/PEDOT hybrid anode possesses a larger active surface area and lower charge‐transfer resistance than three other kinds of anodes, namely, carbon paper (CP), graphene‐modified carbon paper (CP/G), and PEDOT‐modified carbon paper (CP/PEDOT). Scanning electron microscopy was used to investigate the bacteria growth on the four anodes. A compact biofilm was formed on the hybrid anode owing to the electrostatic interaction between the negatively charged bacteria and positively charged PEDOT backbone. The constant‐load (1 KΩ) discharge curves of MFCs with CP, CP/G, CP/PEDOT, and G/PEDOT anodes revealed that the G/PEDOT electrode had good stability and high voltage output. The G/PEDOT anode generated a maximum power density of 873 mW m −2 , which is about 15 times higher than that of CP (55 mW m −2 ) in an H‐shaped dual‐chamber MFC. All the experimental results suggest that the performance of the G/PEDOT hybrid anode is superior to the CP, CP/G, or CP/PEDOT anode.

Barbara Janina Włodarczyk, Paweł Piotr Włodarczyk

Civil and Environmental Engineering Reports • 2024

Due to the constant growth of the world's population, the amount of generated wastewater is also constantly increasing. One of the devices that can use wastewater as a raw material for energy production is a microbial fuel cell (MFC). MFCs technology is constantly evolving. However, to increase its use, it is necessary to improve its efficiency. There are various possibilities to ensure this, such as the use of new electrode materials, new cell designs, or the use of wastewaters from different sources. In this paper the analysis of MFC operation (cell voltage, power, and current density) fed by mixed municipal and industrial wastewaters was shown. Moreover, the change in time of COD was analyzed. Due to cost reduction the membrane-less microbial fuel cell (ML-MFC) was chosen. It was noted that the addition of concentrated process wastewater increases the COD reduction time in the ML-MFC. An increase of generated bioelectricity during fed ML-MFC by mixed municipal and industrial (process wastewater from yeast production) wastewater was demonstrated. The highest values of average cell voltage (598 mV), maximum power (4.47 mW) and maximum current density (0.26 mA·cm-2) were obtained for a 10% share of yeast process wastewater in the mixed wastewater, which fed the ML-MFC.

Anwar Ma'ruf, Agus Mulyadi Purnawanto, Latiful Hayat et al.

International Journal of Energy for a Clean Environment • 2023

Microbial fuel cell is a new technology that utilizes bacteria as biochemicals to convert energy stored in organic/inorganic compounds, which is easily degraded into electrical energy. Apart from being able to produce electrical energy, the implementation of this technology can help solve the problem of processing wastewater resulting from cassava fermentation. The specific aim of the research is to examine the effect of cassava fermentation wastewater concentration and the effect of urea addition on the productivity of electricity produced and the reduction in the quality of cassava fermentation wastewater. From the research results, it can be concluded that the higher the cassava fermentation wastewater concentration, the smaller the electrical energy produced. The optimum initial cassava fermentation wastewater concentration is 20% v/v, with an average volumetric power density produced of 58.56 W/m<sup>3</sup>. The higher the concentration of added urea, the smaller the electrical energy produced. The optimum concentration of urea addition is 0.16-0.33 g/L. There is a linear relationship between the electricity produced and the decrease in total suspended solid (TSS) and total dissolved solid (TDS). The higher the electricity produced, indicating high bacterial activity, will cause a decrease in TSS and TDS.

Yue Dong, Yujie Feng, Youpeng Qu et al.

Scientific Reports • 2015

Abstract Energy self-sufficiency is a highly desirable goal of sustainable wastewater treatment. Herein, a combined system of a microbial fuel cell and an intermittently aerated biological filter (MFC-IABF) was designed and operated in an energy self-sufficient manner. The system was fed with synthetic wastewater (COD = 1000 mg L −1 ) in continuous mode for more than 3 months at room temperature (~25 °C). Voltage output was increased to 5 ± 0.4 V using a capacitor-based circuit. The MFC produced electricity to power the pumping and aeration systems in IABF, concomitantly removing COD. The IABF operating under an intermittent aeration mode (aeration rate 1000 ± 80 mL h −1 ) removed the residual nutrients and improved the water quality at HRT = 7.2 h. This two-stage combined system obtained 93.9% SCOD removal and 91.7% TCOD removal (effluent SCOD = 61 mg L −1 , TCOD = 82.8 mg L −1 ). Energy analysis indicated that the MFC unit produced sufficient energy (0.27 kWh m −3 ) to support the pumping system (0.014 kWh m −3 ) and aeration system (0.22 kWh m −3 ). These results demonstrated that the combined MFC-IABF system could be operated in an energy self-sufficient manner, resulting to high-quality effluent.

Asim Ali Yaqoob, Mohamad Nasir Mohamad Ibrahim, Amira Suriaty Yaakop et al.

Applied Water Science • 2022

Abstract This study aims to improve electron transfer and cobalt remediation efficiency through microbial fuel cells (MFCs) by modifying the electrode material. The fabrication and alteration of the anode can be accomplished by synthesizing biomass-derived graphene oxide (GO) and adding metal oxides (ZnO and TiO 2 ) as modifiers. The prepared GO anode offered 0.148 mW/m 2 power density while GO-ZnO delivered 8.2 times and GO-TiO 2 composite anode delivered 5.3 times higher power density than GO. Similarly, the achieved current density of GO was 39.47 mA/m 2 while GO-ZnO composite anode delivered 75.43 mA/m 2 and GO-TiO 2 composite anode offered 67.54 mA/m 2 . During the biological characterizations of biofilm, the Bacillus sp . and Klebsiella pneumoniae strains were majorly found as exoelectrogens and metal-reducing species. The maximum remediation efficiency of cobalt (II) was 80.10% (GO), 91% (GO-ZnO composite anode), and 88.45% (GO-TiO 2 composite anode) on day 45. The remediation and SEM results of anode biofilm clearly show that the prepared anodes are highly biocompatible with the bacteria. Furthermore, the effect of pH and temperature on MFCs performance are also explained with prepared anodes. Each anode offered significant perspectives in parameter optimizations.

Sigita Bendinskaite, Ingrida Bruzaite, Juste Rozene et al.

Journal of The Electrochemical Society • 2024

The world’s growing energy crisis demands renewable energy sources. This issue can be solved using microbial fuel cells (MFCs). MFCs are biocatalytic systems which convert chemical energy into electrical energy, thereby reducing pollution from hazardous chemical compounds. However, during the development of MFCs, one of the most significant challenges is finding and assessment of microorganisms that generate sufficient redox potential through metabolic and catalytic processes. In this research, we have used Ensifer meliloti (E. meliloti) bacteria to design MFCs based on consecutive action of two redox mediators (9,10 - phenanthrenequinone (PQ) and potassium ferricyanide), which transferred charge between E. meliloti bacteria and graphite rod electrode. A viability study of E. meliloti culture showed that PQ significantly inhibits the growth of bacteria at 0.036 mM. Cyclic voltammograms were registered in the presence of 20 mM of potassium ferricyanide and different concentrations (0.036 and 0.071 mM, 0.11 mM, 0.14 mM, 0.172 mM, 0.32 mM) of PQ. Four days of lasting assessment of the microbial fuel cells in two-electrode systems showed that the maximal open circuit potential during the experiment raised from 174.9 to 234.6 mV. Power increased from 0.392 to 0.741 mW m −2 .

Fan Zhou, Samuel Simon Araya, Ionela Florentina Grigoras et al.

ASME 2014 12th International Conference on Fuel Cell Science, Engineering and Technology • 2014

Degradation tests of two phosphoric acid (PA) doped PBI membrane based HT-PEM fuel cells were reported in this paper to investigate the effects of start/stop and the presence of methanol in the fuel to the performance degradation. Continuous tests with H2 and simulated reformate which was composed of H2, water steam and methanol as the fuel were performed on both single cells. 12-h-startup/12-h-shutdown dynamic tests were performed on the first single cell with pure dry H2 as the fuel and on the second single cell with simulated reformate as the fuel. Along with the tests electrochemical techniques such as polarization curves and electrochemical impedance spectroscopy (EIS) were employed to study the degradation mechanisms of the fuel cells. Both single cells showed an increase in the performance in the H2 continuous tests, because of a decrease in the ORR kinetic resistance probably due to the redistribution of PA between the membrane and electrodes. EIS measurement of first fuel cell during the start/stop test showed that the mass transfer resistance and ohmic resistance increased which can be attributed to the corrosion of carbon support in the catalyst layer and degradation of the PBI membrane. During the continuous test with simulated reformate as the fuel the ORR kinetic resistance and mass transfer resistance of both single cells increased. The performance of the second single cell experienced a slight decrease during the start/stop test with simulated reformate as the fuel.

Shunliang Liu, Yali Feng, Haoran Li

Journal of Chemical Technology & Biotechnology • 2022

Abstract BACKGROUND To understand the effect of electron shuttle compounds on the electron transfer behavior of MFC and the formation process of microbially fabricated nanowires. In this paper, 2,6‐anthraquinone desulfonation (AQDS) and Fe(OH) 3 were used as electron mediator and electron acceptor, respectively, to study the effect of electron mediator on the formation of bio‐nanowires during the growth of Geobacter metallireducens in the double chamber MFC reactor (MFC), and the effects of electron transfer efficiency and electrical current characteristic. RESULTS The results show that the culture process of the Geobacter metallireducens with Fe(OH) 3 as an electron acceptor, the reduction product Fe(II) concentration in solution without AQDS was higher than that with AQDS after 10 days due to the formation of microbial nanowires. In comparison, the Pili protein content of the system without AQDS reached 336 ug/mL, which was higher than the AQDS system. Nanowires increased the transfer efficiency between biofilm and electrodes, which increased the maximum output voltage of MFC was 442 mV. CONCLUSION At the same time, it was found by electrochemical measurements that the nanowire biofilm electrode had a huge peak of the cyclic voltammetry curve, a small activation resistance, and a strong current response signal, indicating that the nanowires enhanced the electrochemical activity of the electrode. In addition, an electron transfer medium (AQDS) inhibited the expression of aromatic amino acids, tryptophan, and mtrC. Moreover, it destroyed the overlapping π‐π orbits of the aromatic parts, resulting in reduced and thinner nanowires and then decreasing the conductivity of synthetic organic materials like metals. © 2022 Society of Chemical Industry (SCI).

Parviz Khujaev, Turobcul Kholmuratov, Jamshed Ismatullozoda Ismatullo et al.

E3S Web of Conferences • 2022

The topical issue of efficient fuel combustion when using hot water boilers is considered. Indeed, this is a very important issue that is directly related to the rational use of resources, reducing the cost of providing thermal energy and reducing the negative impact on the environment. As a result, today the production and operation of hot water boilers must meet high standards of efficiency and environmental friendliness in order to ensure an optimal balance between economic efficiency and environmental protection. Moreover, the development of new energy-saving technologies and fuel combustion systems is an important area of scientific and technological progress to improve people's living conditions and ensure sustainable development. Burning fuel in large quantities leads to certain losses, which reduces the efficiency of the boiler. Therefore, there were mainly small energy-saving furnaces designed for burning fuel. The author proposed a small boiler with a furnace in which a vertical grate is used. Burning any fuel in such a furnace reduced heat loss by 2 times and harmful emissions into the atmosphere by 1.5 times. The efficiency of the heating processes in the boiler was evaluated during one heating season. The cost of providing thermal energy compared to other operating boiler houses amounted to 14400 somoni (1200 dollars), which is 18% less than the initial costs of previous years.

Yajun Wang, Rajendra Prasad Singh, Junyu Zhang et al.

Journal of Water Supply: Research and Technology-Aqua • 2019

Abstract Bioretention cell (BRC) and an enhanced system combining bioretention cell with microbial fuel cell (BRC-MFC) were used to treat domestic wastewater. Nitrogen removal characteristics and permeation characteristics of two systems were investigated by adjusting influent carbon/nitrogen ratio (C/N = 2–20). Results showed that nitrification and denitrification performances were mainly influenced by organic matter and system combination, which further effected the nitrogen removal. When optimal operating parameters were: electrode space of 30 cm, hydraulic load of 1.0 m3/(m2·d) and inlet/reaction time of 1/8 in BRC-MFC system, chemical oxygen demand (COD), total nitrogen (TN) and NH4+ removal efficiencies still reached 97.63, 64, and 42.26%, respectively and achieved high removal efficiency of organic matter and nitrogen simultaneously compared to the BRC system. Efficient supply of electron and phylogenetic diversity of bacterial communities in BRC-MFC process was the main reason to achieve deep denitrification removal. After the V3-V4 variable region of 16S rRNA gene was sequenced by the Miseq high-throughput sequencing method, introduction of MFC enhancement technology affected the microbial community structure in the system. The presence of MFC contributed to an increase in community diversity (from 14 to 19 phyla). The results provide a simple method without kinetic energy for simultaneous denitrification and steady infiltration of bioretention.