Jingyi Zhang, Heyang Yuan, Yelin Deng et al.

The International Journal of Life Cycle Assessment • 2019

Dipak A. Jadhav, Ashvini D. Chendake, Soumya Pandit et al.

Journal of Power Sources • 2024

Alberto Botti, Narcís Pous, Hao-Yi Cheng et al.

Chemical Engineering Journal • 2022

Economic options to retrofit wastewater treatment plants (WWTPs) without tertiary treatments need to be explored. In this regard, bioelectrochemical systems (BES) can be hybridized with existing technologies, upgrading the removal performance of original techniques while avoiding replacement costs. Yet, few demonstrations of merged systems have been given. For the first time, in this work it was built a lab-scale model of a BES merged with a secondary settler, namely e-settler, to enhance the polishing performance of already existing WWTPs. In particular, to concomitantly increase nitrogen removal and perform wastewater (WW) disinfection, avoiding further tertiary treatments. In the e-settlers, nitrogen removal was increased through bioelectrochemical stimulation. Concomitant ammonium and nitrate removal without nitrite accumulation and a negligible amount of nitrous oxide emissions were observed. Ti-MMO as anode material showed a high disinfectant action. In conclusion, it was demonstrated how a simple bioelectrochemical set-up can upgrade existing WWTPs. The following step requires the study at a larger scale, identifying optimal operational and structural parameters for the in-situ application. The main limitations of the e-settlers were discussed, linking them to possible solutions that need to be deepened in a lab-scale model of conventional secondary treatments (activated sludge followed by secondary settler).

Xavier Alexis Walter, Carlo Santoro, John Greenman et al.

Bioelectrochemistry • 2019

The scalability of bioelectrochemical systems is a key parameter for their practical implementation in the real-world. Up until now, only urine-fed self-stratifying microbial fuel cells (SSM-MFCs) have been shown to be scalable in width and length with limited power density losses. For practical reasons, the present work focuses on the scalability of SSM-MFCs in the one dimension that has not yet been investigated, namely height. Three different height conditions were considered (1 cm, 2 cm and 3 cm tall electrodes). The normalised power density of the 2 cm and 3 cm conditions were similar either during the durability test under a hydraulic retention time of ≈39 h (i.e. 15.74 ± 0.99 μW.cm -3 ) and during the polarisation experiments (i.e. 27.79 ± 0.92 μW.cm -3 ). Conversely, the 1 cm condition had lower power densities of 11.23 ± 0.07 μW.cm -3 and 17.73 ± 3.94 μW.cm -3 both during the durability test and the polarisation experiment, respectively. These results confirm that SSM-MFCs can be scaled in all 3 dimensions with minimal power density losses, with a minimum height threshold for the electrode comprised between 1 cm and 2 cm.

Muhammad Imran Din, Amna Ghulam Nabi, Zaib Hussain et al.

International Journal of Energy Research • 2021

With ever increasing waste production worldwide, the development of newly emerging technologies is rising and advancing proportionately. Entailed instalment of sophisticated energy-producing plants is constantly expanding to meet the socio-economic demands of communities and industries. Innumerable superior technologies have been introduced to minimise waste pollution while reducing emissions of greenhouse gases hence, combatting the impact of global warming. This review shows energy conversion technologies including gasification, pyrolysis, incineration, landfill, and bioelectrochemical technologies mainly microbial fuel cell (MFC), microbial electrolysis cells (MECs) and microbial electrosynthesis (MES). Traditionally, incineration and landfill are the main mean of waste conversion but not favourable because of their side effects, economic viability, secondary pollution and difficulty in mechanical compression. Recently, biological processes including anaerobic digestion have gained huge interest but possess some inherent drawbacks and cannot provide a comprehensive solution for future waste management. Among energy converting technologies, bio-electrochemical MFC system is highly preferred as an elementary, clean, safe, economically viable and environmentally beneficial technology. MFC a renewable energy technology possesses multidimensional applications of producing electric power and treat wastewater. In addition, the MFCs can be modified into MEC to generate hydrogen energy from various organic matters. Prospective modification recommendations for scale-up application of this technology are also presented.

Patrícia Leitão, Simona Rossetti, Anthony S. Danko et al.

Bioresource Technology • 2016

Tianjie Ao, Chen‐Guang Liu, Zhao-Yong Sun et al.

Biotechnology Advances • 2024

Sung-Gwan Park, Chaeyoung Rhee, Dipak A. Jadhav et al.

The Science of The Total Environment • 2022

Monika Sharma, El‐Sayed Salama, Nandini Thakur et al.

Chemical Engineering Journal • 2023

Availability of biomass makes biofuel from bioresources more feasible. Recently, algal biomass (AB) and lignocellulosic biomass (LB) have been widely used in bioelectrochemical systems (BESs) for bioelectricity and biohydrogen production. However, no review provides the current scenario of bioelectricity and biohydrogen generation from various biomass and biowaste in BESs. Therefore, the current review provides a recent and in-depth understanding of biomass-specific BESs including biomass selection, pretreatment approaches, dominating microbes, economic feasibility, and pilot-scale up. Biomass of E. prolifera and bamboo (hydrolysate) were reported to have a high ability for bioelectricity generation with maximum power densities of 3810 and 578 mW m−2, respectively. Biohydrogen productions were 1608 and 1017 mL H2 g−1 with fruit waste and S. Japonica, respectively. Previous studies used single biomass in BESs and almost there is no research work on mixed biomass. Co-digestion and/or mixing of biomass (such as AB and LB) or biowaste (lipid-rich and carbohydrate-rich feedstock) would enhance the accessibility of substrates to microbes which could increase the bioelectricity and biohydrogen. The integration of MFCs with primary and secondary units of wastewater treatment plants (WWTPs) is restricted to the utilization of wastewater and sludge (i.e., substrate). Thus, biomass augmentation as an external substrate in WWTP might facilitate the growth of electroactive microbes and can efficiently support the pilot-scale BESs.

Maxime Blatter, Marion Vermeille, Clément Furrer et al.

ACS Sustainable Chemistry & Engineering • 2019

Phosphate recovery from sewage sludge is possible with a bioelectrochemical system (BES) also referred to as microbial fuel/electrolysis cell (MFC, MEC). The investigated process is based on phosphate removal with iron salts, which is extensively used in wastewater treatment. The mechanisms and reaction parameters of the bioelectrochemical phosphate recovery process was examined by modeling and model reactions for future scale up works. The mechanistic analyses concerned the electron reduction process, the role of the pH as well as the observed metal removal capacity. Iron oxidation state analyses showed that the iron reduction mechanism was of negligible importance under microbial electrolysis cell conditions. The cathodic iron reduction was outperformed by fast iron precipitation and phosphate remobilization process depended largely on chemical base (OH–). Fluid particle kinetics and shrinking core modeling determined the relevancy of the reaction parameters in order to accelerate phosphate remobilisation. Rate enhancements were possible at higher pH, increased temperature and faster stirring. With the elucidated mechanisms and reaction kinetics parameters, the scale-up of bioelectrochemical system based phosphate recovery was given a foundation for scale-up works.

De-Chun Xu, Siyuan Zhai, Hao-Yi Cheng et al.

Environmental Research • 2020

Kun Guo, Diana Hidalgo, Tonia Tommasi et al.

Bioresource Technology • 2016

Shuyao Wang, Ademola Adekunle, Vijaya Raghavan

Journal of Cleaner Production • 2022

Jose A. Cornejo, Hua Sheng, Eran Edri et al.

Nature Communications • 2018

By electrochemically coupling microbial and abiotic catalysts, bioelectrochemical systems such as microbial electrolysis cells and microbial electrosynthesis systems synthesize energy-rich chemicals from energy-poor precursors with unmatched efficiency. However, to circumvent chemical incompatibilities between the microbial cells and inorganic materials that result in toxicity, corrosion, fouling, and efficiency-degrading cross-reactions between oxidation and reduction environments, bioelectrochemical systems physically separate the microbial and inorganic catalysts by macroscopic distances, thus introducing ohmic losses, rendering these systems impractical at scale. Here we electrochemically couple an inorganic catalyst, a SnO 2 anode, with a microbial catalyst, Shewanella oneidensis, via a 2-nm-thick silica membrane containing -CN and -NO 2 functionalized p-oligo(phenylene vinylene) molecular wires. This membrane enables electron flow at 0.51 μA cm -2 from microbial catalysts to the inorganic anode, while blocking small molecule transport. Thus the modular architecture avoids chemical incompatibilities without ohmic losses and introduces an immense design space for scale up of bioelectrochemical systems.

Indrasis Das, Sovik Das, Rohan Dixit et al.

Ionics • 2020

Juan Antonio Baeza, Àlex Martínez-Miró, Javier Guerrero et al.

Journal of Power Sources • 2017

Jamison Watson, Tengfei Wang, Buchun Si et al.

Progress in Energy and Combustion Science • 2019

Alba Ceballos‐Escalera, Daniele Molognoni, Pau Bosch‐Jimenez et al.

Applied Energy • 2019

Feng Li, Rui Tang, Baocai Zhang et al.

Research • 2023

Electroactive biofilm plays a crucial rule in the electron transfer efficiency of microbial electrochemical systems (MES). However, the low ability to form biofilm and the low conductivity of the formed biofilm substantially limit the extracellular electron transfer rate of microbial cells to the electrode surfaces in MES. To promote biofilm formation and enhance biofilm conductivity, we develop synthetic biology approach to systematically engineer Shewanella oneidensis , a model exoelectrogen, via modular manipulation of the full-cycle different stages of biofilm formation, namely, from initial contact, cell adhesion, and biofilm growth stable maturity to cell dispersion. Consequently, the maximum output power density of the engineered biofilm reaches 3.62 ± 0.06 W m -2 , 39.3-fold higher than that of the wild-type strain of S. oneidensis , which, to the best our knowledge, is the highest output power density that has ever been reported for the biofilms of the genetically engineered Shewanella strains.

Andreas H. Förster, Sebastian Beblawy, Frederik Golitsch et al.

Biotechnology for Biofuels • 2017

Electrode-assisted fermentations are a new strategy to produce substances of biotechnological value that are more oxidized than the substrates. Here, we show for the first time a process in which the commonly used chassis strain E. coli was tailored for an electrode-assisted fermentation approach branching off from the central metabolite pyruvate. At this early stage, we see promising results regarding carbon and electron recovery and will use further strain development to increase the anaerobic metabolic turnover rate.

Mei Wu, Nuerla Ailijiang, Na Li et al.

Environmental Science and Pollution Research • 2024

André Gemünde, Jonas Gail, Jürgen Janek et al.

SSRN Electronic Journal • 2023

Buchun Si, Huige Xing, Bo Zhou et al.

Renewable and Sustainable Energy Reviews • 2025

Md. Manjurul Haque, Md. Amdadul Haque, Md Khaled Mosharaf et al.

Saudi Journal of Biological Sciences • 2020

Metabolites of azo dyes are often carcinogenic, teratogenic, mutagenic and recalcitrant in nature. In this study, four biofilm consortia such as C1 ( Vitreoscilla sp. ENSG301, Acinetobacter lwoffii ENSG302, Klebsiella pneumoniae ENSG303 and Pseudomonas fluorescens ENSG304), C2 ( Escherichia coli ENSD101, Enterobacter asburiae ENSD102 and E. ludwigii ENSH201), C3 ( E. asburiae ENSD102, Vitreoscilla sp. ENSG301 and Bacillus thuringiensis ENSW401), and C4 ( E. coli ENSD101, E. ludwigii ENSH201 and B. thuringiensis ENSW401) were applied to degrade and detoxify methyl orange (MO), a carcinogenic, sulfonated mono azo dye, used in textile dyeing industry worldwide. The consortia of C1, C2, C3 and C4 showed 97.30, 98.75, 99.51 and 99.29% decolorization, respectively in yeast extract peptone (YEP) broth containing 200 mg L -1 MO within 60 h of incubation in static condition. The optimum pH and temperature for decolorization was 7.0 and 28 °C, respectively. Some divalent metal ions including Mg 2+ , Ca 2+ , Zn 2+ and Mn 2+ could stimulate MO decolorization. UV-Vis spectral analysis showed that the absorption peak at 465 nm originated from the azo (N[bond, double bond]N) bond was completely disappeared within 60 h of incubation. Fourier transform infrared spectroscopy (FTIR) results also revealed that several major peaks including azo bond peak at 1602.6 cm -1 are completely or partly vanished, deformed or shifted. Activities of azoreductase, NADH-DCIP reductase and laccase were significantly increased in the bacterial cells within 60 h of incubation in comparison to that of control (0 h). The chemical oxygen demand was incredibly reduced by 85.37 to 91.44% by these consortia. Accordingly, plant (wheat seed germination) and microbial (growth of the plant probiotic bacteria such as Pseudomonas cedrina ESR12 and Bacillus cereus ESD3 on biodegraded products) toxicity studies showed that biodegraded products of MO are non-toxic. Thus, all these consortia can be utilized in bioremediation of MO from wastewater for safe disposal into environment. To our knowledge, this is the first report on degradation and detoxification of MO from wastewater by bacterial biofilm consortia.

Catherine G. Mar‐Pineda, Héctor M. Poggi‐Varaldo, M.T. Ponce‐Noyola et al.

The Canadian Journal of Chemical Engineering • 2021

Abstract In this research we evaluated the effect of adding zero‐valent iron nanoparticles (ZVI‐NP) to a complete mix bioelectrochemical slurry reactors (BESR) on the remediation of a clayish soil with a high content of organic matter, contaminated with lindane. Five BESR were loaded with a clayish polluted soil (100 mg lindane/kg ds ), known concentrations of ZVI‐NP, liquid medium, and sulphate‐reducing inoculum to give a 33% w/v soil concentration. A one‐factor experimental design was used, where the effect of nanoparticles concentration [NP] on lindane removal efficiency ( η lin ) and other response variables were evaluated. The [NP] levels were 0.0 (background control with electrical connection, BCWC), 2.5 (Exp1), 5.0 (Exp2), and 7.5 gNP/kg ds (Exp3). Maximum η lin (95%) was attained in Exp2 (5 gNP/kg ds ). Beyond this level the η lin slightly decreased (Exp3 with 85% η lin .) Approximately 40%‐57% of lindane was removed in the first 24 hours during a rapid kinetics phase. No metabolites of lindane degradation were detected after 30 days of operation in all the BESR. Energy production increased with [NP]; Exp3 generated 4.3 MJ/tonne ds at 30 days, whereas the other treatments produced energy between 1.6 MJ/tonne ds ‐1.2 MJ/tonne ds . Bioelectrical energy could partially offset the requirements of BESR mixing energy. Overall performance evaluation using an ad hoc multicriteria framework indicated that BESR followed the order Exp2 > Exp3 > Exp1 ~ BCWC > ABCWOC (abiotic control without electrical connection). There was a significant, positive effect of the combined BESR and ZVI‐NP technology for the remediation of heavy soils contaminated with lindane.

Cheng Li, Clare E. Reimers, Yvan Alleau

Biogeosciences • 2020

Abstract. Cable bacteria (CB) are multicellular, filamentous bacteria within the family of Desulfobulbaceae that transfer electrons longitudinally from cell to cell to couple sulfide oxidation and oxygen reduction in surficial aquatic sediments. In the present study, electrochemical reactors that contain natural sediments are introduced as a tool for investigating the growth of CB on electrodes poised at an oxidizing potential. Our experiments utilized sediments from Yaquina Bay, Oregon, USA, and we include new phylogenetic analyses of separated filaments to confirm that CB from this marine location cluster with the genus “Candidatus Electrothrix”. These CB may belong to a distinctive lineage, however, because their filaments contain smaller cells and a lower number of longitudinal ridges compared to cables described from other locales. The results of a 135 d bioelectrochemical reactor experiment confirmed that these CB can migrate out of reducing sediments and grow on oxidatively poised electrodes suspended in anaerobic seawater. CB filaments and several other morphologies of Desulfobulbaceae cells were observed by scanning electron microscopy and fluorescence in situ hybridization on electrode surfaces, albeit in low densities and often obscured by mineral precipitation. These findings provide new information to suggest what kinds of conditions will induce CB to perform electron donation to an electrode surface, further informing future experiments to culture CB outside of a sediment matrix.

Alyssa Y. Zhou, Moshe Baruch, Caroline M. Ajo‐Franklin et al.

PLoS ONE • 2017

Current technologies are lacking in the area of deployable, in situ monitoring of complex chemicals in environmental applications. Microorganisms metabolize various chemical compounds and can be engineered to be analyte-specific making them naturally suited for robust chemical sensing. However, current electrochemical microbial biosensors use large and expensive electrochemistry equipment not suitable for on-site, real-time environmental analysis. Here we demonstrate a miniaturized, autonomous bioelectronic sensing system (BESSY) suitable for deployment for instantaneous and continuous sensing applications. We developed a 2x2 cm footprint, low power, two-channel, three-electrode electrochemical potentiostat which wirelessly transmits data for on-site microbial sensing. Furthermore, we designed a new way of fabricating self-contained, submersible, miniaturized reactors (m-reactors) to encapsulate the bacteria, working, and counter electrodes. We have validated the BESSY's ability to specifically detect a chemical amongst environmental perturbations using differential current measurements. This work paves the way for in situ microbial sensing outside of a controlled laboratory environment.

Pewee Datoo Kolubah, Hend Omar Mohamed, Mohamed Nejib Hedhili et al.

Journal of environmental chemical engineering • 2024

Johannes Eberhard Reiner, Benjamin Korth, Miriam Edel

ChemElectroChem • 2024

Abstract Oxic microbial electrosynthesis (oMES) allows the utilization of renewable electricity and industrial gas streams containing CO 2 and O 2 for biomass production by cultivating aerobic, autotrophic, hydrogen‐oxidizing bacteria, commonly known as Knallgas bacteria. oMES is likely not a direct competitor to conventional anoxic microbial electrosynthesis as harnessing aerobic hydrogen‐oxidizing bacteria depends on energetically inefficient assimilatory CO 2 reduction pathways. However, it might be a complementary approach to classical biomass production from the perspective of limited land use and the availability of cheap renewable energy. The best characterized Knallgas bacterium is Cupriavidus necator . Extensively studied as lithoautotrophic production host, C. necator already offers a broad arsenal of genetic tools. In contrast, mechanistical knowledge about the recently discovered Kyrpidia spormannii is limited, but this species shows remarkable growth when cultivated as cathodic biofilm in bioelectrochemical systems. In addition, first experiments indicate a low energy demand for biomass production, which is in the order of magnitude of gas fermentation with C. necator or heterotrophic and methanotrophic technologies. Still, many aspects of the electrochemical cultivation of K. spormannii need to be better understood and rigorously improved to be a competitive technology in the making, including electron transfer and microbial kinetics, cultivation conditions, mass and energy balances, and reactor design.

Cynthia J. Castro, Kamal Ziad Taha, Itzé Kenney et al.

Water • 2022

Bioelectrochemical systems with denitrifying biocathodes have been of interest for the removal of nitrate in decentralized wastewater treatment applications. Only a few studies have directly focused on this application, but the removal rates have been very low. This study evaluated the operational parameters that affect the nitrate removal of two-chambered microbial fuel cells (MFCs) with a biocathode, particularly, the carbon to nitrogen ratio (C:N) and proton diffusivity across electrode chambers. The results show that proton diffusion across a proton exchange membrane is not a limiting step in nitrogen removal performance. At C:N ratios of 4 and 8, biocathodes with a continuously supplied carbon source at the anode were able to achieve complete nitrogen removal at a rate of 0.97 ± 0.21 and 1.15 ± 0.13 mg N L−1 d−1, respectively. However, as the C:N ratio increased from 4, 8, 16, and 32, the electrode potentials decreased accordingly. Ratio 4 C:N had a cathodic reduction potential of +66.1 ± 5.3 mV vs. SHE and dropped to −78.6 ± 9.8 mV vs. SHE at 32 C:N. The cathode electrode potential can be controlled by way of the carbon concentrations at the anode, which can have major indirect implications on the evolution of cathodic microbial communities that have preference to particular ranges of reduction potentials. The cathodic biofilms in this study were dominated by the phyla Proteobacteria, Acidobacteria, Bacteroidetes and Nitrospirae, which are known to have key denitrifying microorganisms. The genus Stenotrophomonas was found in abundance within the attached cathode biofilm and to a lesser extent in the suspended biomass. Vibrio, Acidobacteria_Gp4, Nitrosomonas, and Candidatus Competibacter were also cultivated in both the suspended and attached biomass. Nitrospira was only found in the attached biofilm. Regardless of operational scheme, nitrogen removal was improved at low C:N ratios, with 8 C:N having the best performance overall. This indicates that higher C:N ratios than were previously explored (>4 C:N) provide sufficient coulombs to facilitate denitrification at the cathode even while the anodic CEs remain low. Reactor design modifications should be considered to fully support robust denitrifying communities, enhancing the overall nitrogen removal for decentralized wastewater treatment applications.

Alba Ceballos‐Escalera, Narcís Pous, M. Dolors Balaguer et al.

Chemosphere • 2024

Nitrate-contaminated groundwater is a pressing issue in rural areas, where up to 40 % of the population lacks access to safely managed drinking water services. The high costs and complexity of centralised treatment in these regions exacerbate this problem. To address this challenge, the present study proposes electro-bioremediation as a more accessible decentralised alternative. Specifically, the main focus of this study is developing and evaluating a compact reactor designed to accomplish simultaneous nitrate removal and groundwater disinfection. Significantly, this study has established a new benchmark for nitrate reduction rate within bioelectrochemical reactors, achieving the maximum reported rate of 5.0 ± 0.3 kg NO 3 - m -3 NCC d -1 at an HRT cat of 0.7 h. Furthermore, thein-situ generation of free chlorine was effective for water disinfection, resulting in a residual concentration of up to 4.4 ± 1.1 mg Cl 2 L -1 in the effluent at the same HRT cat of 0.7 h. These achievements enabled the treated water to meet the drinking water standards for nitrogen compounds (nitrate, nitrite, and nitrous oxide) as well as pathogens content (T. coliforms, E. coli, and Enterococcus). In conclusion, this study demonstrates the potential of the electro-bioremediation of nitrate-contaminated groundwater as a decentralised water treatment system in rural areas with a competitive operational cost of 1.05 ± 0.16 € m -3 .

Daniele Cecconet, Silvia Bolognesi, Arianna Callegari et al.

Heliyon • 2019

Bioelectrochemical systems (BES) application was proposed for a variety of specific uses, due to these systems' characteristics: electrodes can act as virtually inexhaustible electron acceptors/donors, offering a growth-support surface for microorganisms, and stimulating naturally-occurring microbial degradation activities. In situ, groundwater denitrification therefore seems to be a potential candidate for their use. In this study, buried biocathodes were operated in laboratory settings for the simulation of in situ groundwater denitrification. Two alternative configurations were tested: biocathode buried in sand, and biocathode buried in gravel. A control test with a biocathode in absence of sand/gravel was also performed. In all the cases, biocathodes were driven by power supply or potentiostat to guarantee a steady electron flux to the cathode. The presence of sand and gravel strongly influenced the denitrification process: in both configurations, accumulation of intermediate N-forms was detected, suggesting that the denitrification process was only partially achieved. In addition, a significant decrease (in the 20-36% range) in nitrate removal rates was measured in sand and gravel setups compared to the control reactor; this issue could be attributed to lack of recirculation that limited contact between substrate and electrode-adherent biofilm. Biocathodes buried in gravel obtained better results than those buried in sand due to the lower packing of the medium. The results of this study suggest that, in order to achieve successful in situ treatment, special design of submerged-biocathodic BESs is necessary.

Yuting Guo, Luís F. M. Rosa, Susann Müller et al.

Environmental Science and Ecotechnology • 2020

A laminar flow bioelectrochemical systems (BES) was designed and benchmarked using microbial anodes dominated with Geobacter spp. The reactor architecture was based on modeled flow fields, the resulting structure was 3D printed and used for BES manufacturing. Stratification of the substrate availability within the reactor channels led to heterogeneous biomass distribution, with the maximum biomass found mainly in the initial/middle channels. The anode performance was assessed for different hydraulic retention times while coulombic efficiencies of up to 100% (including also hydrogen recycling from the cathode) and current densities of up to 75 μA cm -2 at an anode surface to volume ratio of 1770 cm 2 L -1 after 35 days were achieved. This low current density can be clearly attributed to the heterogeneous distributions of biomass and the stratification of the microbial community structure. Further, it was shown that time and space resolved analysis of the reactor microbiomes per channel is feasible using flow cytometry.

Matteo Tucci, A. Milani, Marco Resitano et al.

Journal of environmental chemical engineering • 2022

Microbial electrochemical technologies (MET) are promising for the remediation of groundwater pollutants such as petroleum hydrocarbons (PH). Indeed, MET can provide virtually inexhaustible electron donors or acceptors directly in the subsurface environment. However, the degradation mechanisms linking contaminants removal to electric current flow are still largely unknown, hindering the development of robust design criteria. Here, we analysed the degradation of toluene, a model PH, in a bioelectrochemical reactor known as “bioelectric well” operated in continuous-flow mode at various influent toluene concentrations. With increasing concentration of toluene, the removal rate increased while the current tended to a plateau, hence the columbic efficiency decreased. Operation at open circuit confirmed that the bioelectrochemical degradation of toluene proceeded via a syntrophic pathway involving cooperation between different microbial populations. First of all, hydrocarbon degraders quickly converted toluene into metabolic intermediates probably by breaking the aromatic ring upon fumarate addition. Subsequently, fermentative bacteria converted these intermediates into volatile fatty acids (VFA) and likely also H2, which were then used as substrates by electroactive microorganisms forming the anodic biofilm. As toluene degradation is faster than subsequent conversion steps, the increase in intermediate concentration could not result in a current increase. This work provides valuable insights on the syntrophic degradation of BTEX, which are essential for the application of microbial electrochemical system to groundwater remediation of petroleum hydrocarbons.

Lan Tang, Jiamei Huang, Chuanyan Zhuang et al.

Water Research • 2024

Dídac Recio-Garrido, B. Tartakovsky, Pascal Perrier

IFAC-PapersOnLine • 2016

Reactor staging is widely used in wastewater treatment where treatment norms are achieved by connecting two or more reactors in series. The first reactor operates at high carbon source loads and the last reactor performs the final polishing. Microbial Fuel Cells (MFCs) are bioelectrochemical devices designed for direct electricity production from organic matter. Periodic connection of the MFC external electrical resistance was demonstrated to increase performance. An engineering tool to understand this periodic mode of operation is developed. Effluent quality control can be ensured by developing control strategies able to reject variability in the influent concentration while tracking a desired set-point.

Hassan Mohammadi Khalfbadam, Maneesha P. Ginige, Ranjan Sarukkalige et al.

Chemical Engineering Journal • 2016

Matteo Tucci, David Fernández‐Verdejo, Marco Resitano et al.

Chemosphere • 2023

Subsurface co-contamination by multiple pollutants can be challenging for the design of bioremediation strategies since it may require promoting different and often antagonistic degradation pathways. Here, we investigated the simultaneous degradation of toluene and chloroform (CF) in a continuous-flow anaerobic bioelectrochemical reactor. As a result, 47 μmol L -1 d -1 of toluene and 60 μmol L -1 d -1 of CF were concurrently removed, when the anode was polarized at +0.4 V vs. Standard Hydrogen Electrode (SHE). Analysis of the microbial community structure and key functional genes allowed to identify the involved degradation pathways. Interestingly, when acetate was supplied along with toluene, to simulate the impact of a readily biodegradable substrate on process performance, toluene degradation was adversely affected, likely due to competitive inhibition effects. Overall, this study proved the efficacy of the developed bioelectrochemical system in simultaneously treating multiple groundwater contaminants, paving the way for the application in real-world scenarios.

Yu Zhou, Lijun Tang, Zhongliang Liu et al.

Biochemical Engineering Journal • 2017

Elisa Casula, Daniele Molognoni, Eduard Borràs et al.

Journal of Power Sources • 2021