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Spiess S, Kucera J, Vaculovic T, Birklbauer L, Habermaier C, Conde AS, Mandl M, Haberbauer M. Zinc recovery from bioleachate using a microbial electrolysis cell and comparison with selective precipitation. Front Microbiol 2023; 14:1238853. [PMID: 37664121 PMCID: PMC10469928 DOI: 10.3389/fmicb.2023.1238853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/01/2023] [Indexed: 09/05/2023] Open
Abstract
Metal recycling is essential for strengthening a circular economy. Microbial leaching (bioleaching) is an economical and environmentally friendly technology widely used to extract metals from insoluble ores or secondary resources such as dust, ashes, and slags. On the other hand, microbial electrolysis cells (MECs) would offer an energy-efficient application for recovering valuable metals from an aqueous solution. In this study, we investigated a MEC for Zn recovery from metal-laden bioleachate for the first time by applying a constant potential of -100 mV vs. Ag/AgCl (3 M NaCl) on a synthetic wastewater-treating bioanode. Zn was deposited onto the cathode surface with a recovery efficiency of 41 ± 13% and an energy consumption of 2.55 kWh kg-1. For comparison, Zn recovery from zinc sulfate solution resulted in a Zn recovery efficiency of 100 ± 0% and an energy consumption of 0.70 kWh kg-1. Furthermore, selective metal precipitation of the bioleachate was performed. Individual metals were almost completely precipitated from the bioleachate at pH 5 (Al), pH 7 (Zn and Fe), and pH 9 (Mg and Mn).
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Affiliation(s)
| | - Jiri Kucera
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czechia
| | - Tomas Vaculovic
- Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czechia
| | | | | | | | - Martin Mandl
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czechia
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2
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Spiess S, Sasiain Conde A, Kucera J, Novak D, Thallner S, Kieberger N, Guebitz GM, Haberbauer M. Bioelectrochemical methanation by utilization of steel mill off-gas in a two-chamber microbial electrolysis cell. Front Bioeng Biotechnol 2022; 10:972653. [PMID: 36159676 PMCID: PMC9500408 DOI: 10.3389/fbioe.2022.972653] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 08/11/2022] [Indexed: 11/30/2022] Open
Abstract
Carbon capture and utilization has been proposed as one strategy to combat global warming. Microbial electrolysis cells (MECs) combine the biological conversion of carbon dioxide (CO2) with the formation of valuable products such as methane. This study was motivated by the surprising gap in current knowledge about the utilization of real exhaust gas as a CO2 source for methane production in a fully biocatalyzed MEC. Therefore, two steel mill off-gases differing in composition were tested in a two-chamber MEC, consisting of an organic substrate-oxidizing bioanode and a methane-producing biocathode, by applying a constant anode potential. The methane production rate in the MEC decreased immediately when steel mill off-gas was tested, which likely inhibited anaerobic methanogens in the presence of oxygen. However, methanogenesis was still ongoing even though at lower methane production rates than with pure CO2. Subsequently, pure CO2 was studied for methanation, and the cathodic biofilm successfully recovered from inhibition reaching a methane production rate of 10.8 L m−2d−1. Metagenomic analysis revealed Geobacter as the dominant genus forming the anodic organic substrate-oxidizing biofilms, whereas Methanobacterium was most abundant at the cathodic methane-producing biofilms.
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Affiliation(s)
- Sabine Spiess
- K1-MET GmbH, Linz, Austria
- *Correspondence: Sabine Spiess,
| | | | - Jiri Kucera
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czechia
| | - David Novak
- Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czechia
| | | | | | - Georg M. Guebitz
- ACIB GmbH (Austrian Centre of Industrial Biotechnology), Graz, Austria
- Department of Agrobiotechnology, Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences Vienna, Tulln an der Donau, Austria
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Aryal N, Zhang Y, Bajracharya S, Pant D, Chen X. Microbial electrochemical approaches of carbon dioxide utilization for biogas upgrading. CHEMOSPHERE 2022; 291:132843. [PMID: 34767847 DOI: 10.1016/j.chemosphere.2021.132843] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/11/2021] [Accepted: 11/07/2021] [Indexed: 06/13/2023]
Abstract
Microbial electrochemical approach is an emerging technology for biogas upgrading through carbon dioxide (CO2) reduction and biomethane (or value-added products) production. There is limited literature critically reviewing the latest scientific developments on the bioelectrochemical system (BES) based biogas upgrading technologies, including CO2 reduction efficiency, methane (CH4) yields, reactor operating conditions, and electrode materials tested in the BES reactor. This review analyzes the reported performance and identifies crucial parameters considered for future optimization, which is currently missing. Further, the performances of BES approach of biogas upgrading under various operating settings in particular fed-batch, continuous mode in connection to the microbial dynamics and cathode materials have been thoroughly scrutinized and discussed. Additionally, other versatile application options associated with BES based biogas upgrading, such as resource recovery, are presented. Three-dimensional electrode materials have shown superior performance in supplying the electrons for the reduction of CO2 to CH4. Most of the studies on the biogas upgrading process conclude hydrogen (H2) mediated electron transfer mechanism in BES biogas upgrading.
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Affiliation(s)
- Nabin Aryal
- Department of Microsystems, University of South-Eastern Norway, Borre, Norway.
| | - Yifeng Zhang
- Department of Environmental Engineering, Technical University of Denmark, Denmark
| | - Suman Bajracharya
- Biochemical Process Engineering Department, Luleå University of Technology, Sweden
| | - Deepak Pant
- Separation and Conversion Technology, Flemish Institute for Technological Research (VITO), Boeretang 200, Mol, 2400, Belgium
| | - Xuyuan Chen
- Department of Microsystems, University of South-Eastern Norway, Borre, Norway
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Wang XT, Zhang YF, Wang B, Wang S, Xing X, Xu XJ, Liu WZ, Ren NQ, Lee DJ, Chen C. Enhancement of methane production from waste activated sludge using hybrid microbial electrolysis cells-anaerobic digestion (MEC-AD) process - A review. BIORESOURCE TECHNOLOGY 2022; 346:126641. [PMID: 34973405 DOI: 10.1016/j.biortech.2021.126641] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 12/22/2021] [Accepted: 12/24/2021] [Indexed: 06/14/2023]
Abstract
Hybrid microbial electrolysis cells-anaerobic digestion (MEC-AD) was proved to increase methane productivity and methane yield of waste activated sludge (WAS) by establishing direct interspecies electron transfer method and enriching functional microorganisms. This review first summarized the pretreatment methods of WAS for MEC-AD and then reviewed the reactor configurations, operation parameters, and the economic benefit of MEC-AD. Furthermore, the enhancement mechanisms of MEC-AD were reviewed based on the analysis of thermodynamics and microbial community. It was found that the decrease of hydrogen partial pressure due to the hydrogenotrophic methanogens enriched in cathodic biofilm and direct interspecies electron transfer between exoelectrogens and anode were the core mechanisms for improving acidogenesis, acetogenesis, and methanogenesis. Finally, the potentially technological issues that need to be addressed to increase energy efficiency in large-scale MEC-AD processes were discussed.
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Affiliation(s)
- Xue-Ting Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province 150090, China; Department of Environmental Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Yi-Feng Zhang
- Department of Environmental Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Bo Wang
- Department of Environmental Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Song Wang
- Department of Environmental Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Xue Xing
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province 150090, China
| | - Xi-Jun Xu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province 150090, China
| | - Wen-Zong Liu
- School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China
| | - Nan-Qi Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province 150090, China
| | - Duu-Jong Lee
- Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan
| | - Chuan Chen
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province 150090, China.
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Cristiani L, Ferretti J, Zeppilli M. Electron Recycle Concept in a Microbial Electrolysis Cell for Biogas Upgrading. Chem Eng Technol 2021. [DOI: 10.1002/ceat.202100534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Lorenzo Cristiani
- University of Rome Sapienza Department of Chemistry Piazzale Aldo Moro 5 00185 Rome Italy
| | - Jacopo Ferretti
- University of Rome Sapienza Department of Chemistry Piazzale Aldo Moro 5 00185 Rome Italy
| | - Marco Zeppilli
- University of Rome Sapienza Department of Chemistry Piazzale Aldo Moro 5 00185 Rome Italy
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Xu S, Qiao Z, Luo L, Sun Y, Wong JWC, Geng X, Ni J. On-site CO 2 bio-sequestration in anaerobic digestion: Current status and prospects. BIORESOURCE TECHNOLOGY 2021; 332:125037. [PMID: 33840612 DOI: 10.1016/j.biortech.2021.125037] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
The advantages of anaerobic digestion (AD) technology in organic solid waste treatment for bioenergy recovery are evidenced in worldwide. Recently, more attention has been paid to on-site biogas research, as well as biogenic CO2 sequestration from AD plant, to promote "carbon neutral". Single-phase and two-phase AD system can be incorporated with various CO2 bioconversion technologies through H2 mediated CO2 bioconversion (in-situ and ex-situ biogas upgrading), or other emerging strategies for CO2 fixation without exogenous H2 injection; these include in-situ direct interspecies electron transfer reinforcement, electromethanogenesis, and off-gas reutilization. The existing and potential scenarios for on-site CO2 bio-sequestration within the AD framework are reviewed from the perspectives of metabolic pathways, functional microorganisms, the limitations on reaction kinetics. This review concluded that on-site CO2 bio-sequestration is a promising solution to reduce greenhouse gas emissions and increase renewable energy recovery.
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Affiliation(s)
- Suyun Xu
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Zihao Qiao
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Liwen Luo
- Institute of Bioresource and Agriculture, Hong Kong Baptist University, Hong Kong Special Administrative Region, China; Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region, China
| | - Yongqi Sun
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Jonathan Woon-Chung Wong
- Institute of Bioresource and Agriculture, Hong Kong Baptist University, Hong Kong Special Administrative Region, China; Department of Biology, Hong Kong Baptist University, Hong Kong Special Administrative Region, China.
| | - Xueyu Geng
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Jing Ni
- School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 200093, China
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Singh L, Miller AG, Wang L, Liu H. Scaling-up up-flow microbial electrolysis cells with a compact electrode configuration for continuous hydrogen production. BIORESOURCE TECHNOLOGY 2021; 331:125030. [PMID: 33823486 DOI: 10.1016/j.biortech.2021.125030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/12/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Maintaining high current densities is a key challenge in scaling-up microbial electrolysis cell (MEC) reactors. In this study, a novel 10 L MEC reactor with a total electrode surface area greater than 1 m2 was designed and evaluated to maximize the current density and H2 recovery. Performances of the reactor suggest that the longitudinal structure with parallel vertical orientation of the electrodes encouraged high fluid mixing and the sheet metal electrode frames provided distributed electrical connection. Results also demonstrated that the electrode pairs located next to reactor walls decreased current density, as did separating the electrodes with separators. High volumetric H2 production rate of 5.9 L/L/d was achieved at a volumetric current density of 970 A/m3 (34 A/m2). Moreover, the observed current densities of the large reactor were accurately predicted based on the internal resistance analysis of small scale MECs (0.15 L), demonstrating the scalability of the single chamber MEC design.
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Affiliation(s)
- Lakhveer Singh
- Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97333, USA; Department of Environmental Science, SRM University-AP, Amaravati, Andhra Pradesh 522502, India
| | - Andrew G Miller
- Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97333, USA
| | - Luguang Wang
- Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97333, USA
| | - Hong Liu
- Department of Biological and Ecological Engineering, Oregon State University, Corvallis, OR 97333, USA.
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Spiess S, Kucera J, Seelajaroen H, Sasiain A, Thallner S, Kremser K, Novak D, Guebitz GM, Haberbauer M. Impact of Carbon Felt Electrode Pretreatment on Anodic Biofilm Composition in Microbial Electrolysis Cells. BIOSENSORS-BASEL 2021; 11:bios11060170. [PMID: 34073192 PMCID: PMC8229196 DOI: 10.3390/bios11060170] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/20/2021] [Accepted: 05/21/2021] [Indexed: 01/04/2023]
Abstract
Sustainable technologies for energy production and storage are currently in great demand. Bioelectrochemical systems (BESs) offer promising solutions for both. Several attempts have been made to improve carbon felt electrode characteristics with various pretreatments in order to enhance performance. This study was motivated by gaps in current knowledge of the impact of pretreatments on the enrichment and microbial composition of bioelectrochemical systems. Therefore, electrodes were treated with poly(neutral red), chitosan, or isopropanol in a first step and then fixed in microbial electrolysis cells (MECs). Four MECs consisting of organic substance-degrading bioanodes and methane-producing biocathodes were set up and operated in batch mode by controlling the bioanode at 400 mV vs. Ag/AgCl (3M NaCl). After 1 month of operation, Enterococcus species were dominant microorganisms attached to all bioanodes and independent of electrode pretreatment. However, electrode pretreatments led to a decrease in microbial diversity and the enrichment of specific electroactive genera, according to the type of modification used. The MEC containing isopropanol-treated electrodes achieved the highest performance due to presence of both Enterococcus and Geobacter. The obtained results might help to select suitable electrode pretreatments and support growth conditions for desired electroactive microorganisms, whereby performance of BESs and related applications, such as BES-based biosensors, could be enhanced.
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Affiliation(s)
- Sabine Spiess
- K1-MET GmbH, Stahlstrasse 14, 4020 Linz, Austria; (A.S.); (S.T.); (M.H.)
- ACIB GmbH (Austrian Centre of Industrial Biotechnology), Krenngasse 37/2, 8010 Graz, Austria;
- Correspondence:
| | - Jiri Kucera
- Department of Biochemistry, Faculty of Science, Masaryk University, Kamenice 753/5, 62500 Brno, Czech Republic; (J.K.); (D.N.)
| | - Hathaichanok Seelajaroen
- Linz Institute for Organic Solar Cells (LIOS), Institute of Physical Chemistry, Johannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz, Austria;
| | - Amaia Sasiain
- K1-MET GmbH, Stahlstrasse 14, 4020 Linz, Austria; (A.S.); (S.T.); (M.H.)
| | - Sophie Thallner
- K1-MET GmbH, Stahlstrasse 14, 4020 Linz, Austria; (A.S.); (S.T.); (M.H.)
- ACIB GmbH (Austrian Centre of Industrial Biotechnology), Krenngasse 37/2, 8010 Graz, Austria;
| | - Klemens Kremser
- Department of Agrobiotechnology, Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences Vienna, Konrad-Lorenz-Strasse 20, 3430 Tulln an der Donau, Austria;
| | - David Novak
- Department of Biochemistry, Faculty of Science, Masaryk University, Kamenice 753/5, 62500 Brno, Czech Republic; (J.K.); (D.N.)
| | - Georg M. Guebitz
- ACIB GmbH (Austrian Centre of Industrial Biotechnology), Krenngasse 37/2, 8010 Graz, Austria;
- Department of Agrobiotechnology, Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences Vienna, Konrad-Lorenz-Strasse 20, 3430 Tulln an der Donau, Austria;
| | - Marianne Haberbauer
- K1-MET GmbH, Stahlstrasse 14, 4020 Linz, Austria; (A.S.); (S.T.); (M.H.)
- ACIB GmbH (Austrian Centre of Industrial Biotechnology), Krenngasse 37/2, 8010 Graz, Austria;
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Zeppilli M, Cristiani L, Dell'Armi E, Villano M. Potentiostatic vs galvanostatic operation of a Microbial Electrolysis Cell for ammonium recovery and biogas upgrading. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2020.107886] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Effects of the Feeding Solution Composition on a Reductive/Oxidative Sequential Bioelectrochemical Process for Perchloroethylene Removal. Processes (Basel) 2021. [DOI: 10.3390/pr9030405] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants due to their improper use in several industrial activities. Specialized microorganisms are able to perform the reductive dechlorination (RD) of high-chlorinated CAHs such as perchloroethylene (PCE), while the low-chlorinated ethenes such as vinyl chloride (VC) are more susceptible to oxidative mechanisms performed by aerobic dechlorinating microorganisms. Bioelectrochemical systems can be used as an effective strategy for the stimulation of both anaerobic and aerobic microbial dechlorination, i.e., a biocathode can be used as an electron donor to perform the RD, while a bioanode can provide the oxygen necessary for the aerobic dechlorination reaction. In this study, a sequential bioelectrochemical process constituted by two membrane-less microbial electrolysis cells connected in series has been, for the first time, operated with synthetic groundwater, also containing sulphate and nitrate, to simulate more realistic process conditions due to the possible establishment of competitive processes for the reducing power, with respect to previous research made with a PCE-contaminated mineral medium (with neither sulphate nor nitrate). The shift from mineral medium to synthetic groundwater showed the establishment of sulphate and nitrate reduction and caused the temporary decrease of the PCE removal efficiency from 100% to 85%. The analysis of the RD biomarkers (i.e., Dehalococcoides mccartyi 16S rRNA and tceA, bvcA, vcrA genes) confirmed the decrement of reductive dechlorination performances after the introduction of the synthetic groundwater, also characterized by a lower ionic strength and nutrients content. On the other hand, the system self-adapted the flowing current to the increased demand for the sulphate and nitrate reduction, so that reducing power was not in defect for the RD, although RD coulombic efficiency was less.
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Dykstra CM, Cheng C, Pavlostathis SG. Comparison of Carbon Dioxide with Anaerobic Digester Biogas as a Methanogenic Biocathode Feedstock. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:8949-8957. [PMID: 32544322 DOI: 10.1021/acs.est.9b07438] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
BES biogas upgrading studies have typically used bicarbonate or commercial gas mixtures as a biocathode substrate instead of anaerobic digester biogas. Therefore, the objective of this study was to (i) compare the performance of a methanogenic BES between CO2-fed and biogas-fed cycles; (ii) investigate possible factors that may account for observed performance differences; and (iii) assess the performance of a biogas-fed biocathode at various applied cathode potentials. The maximum 1-d CH4 production rate in a biogas-fed biocathode (3003 mmol/m2-d) was 350% higher than in a CO2-fed biocathode (666 mmol/m2-d), and the biogas-fed biocathode was capable of maintaining high performance despite a variable biogas feed composition. Anode oxidation of reduced gases (e.g., CH4 and H2S) from biogas may theoretically contribute 4% to 35% of the total charge transfer from anode to cathode at applied cathode potentials of -0.80 to -0.55 V (vs SHE). The introduction of biogas did not significantly change the biocathode archaeal community (dominated by a Methanobrevibacter sp. phylotype), but the bacterial community shifted away from Bacteroidetes and toward Proteobacteria, which may have contributed to the improved performance of the biogas-fed system. This study shows that anaerobic digester biogas is a promising biocathode feedstock for BES biogas upgrading.
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Affiliation(s)
- Christy M Dykstra
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0512, United States
- School of Civil, Construction, and Environmental Engineering, San Diego State University, San Diego, California 92182-0003, United States
| | - Cheng Cheng
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0512, United States
- College of Environment and Ecology, Chongqing University, Chongqing 400045, P. R. China
| | - Spyros G Pavlostathis
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0512, United States
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Cristiani L, Zeppilli M, Porcu C, Majone M. Ammonium Recovery and Biogas Upgrading in a Tubular Micro-Pilot Microbial Electrolysis Cell (MEC). Molecules 2020; 25:E2723. [PMID: 32545472 PMCID: PMC7356612 DOI: 10.3390/molecules25122723] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/01/2020] [Accepted: 06/10/2020] [Indexed: 11/20/2022] Open
Abstract
Here, a 12-liter tubular microbial electrolysis cell (MEC) was developed as a post treatment unit for simultaneous biogas upgrading and ammonium recovery from the liquid effluent of an anaerobic digestion process. The MEC configuration adopted a cation exchange membrane to separate the inner anodic chamber and the external cathodic chamber, which were filled with graphite granules. The cathodic chamber performed the CO2 removal through the bioelectromethanogenesis reaction and alkalinity generation while the anodic oxidation of a synthetic fermentate partially sustained the energy demand of the process. Three different nitrogen load rates (73, 365, and 2229 mg N/Ld) were applied to the inner anodic chamber to test the performances of the whole process in terms of COD (Chemical Oxygen Demand) removal, CO2 removal, and nitrogen recovery. By maintaining the organic load rate at 2.55 g COD/Ld and the anodic chamber polarization at +0.2 V vs. SHE (Standard Hydrogen Electrode), the increase of the nitrogen load rate promoted the ammonium migration and recovery, i.e., the percentage of current counterbalanced by the ammonium migration increased from 1% to 100% by increasing the nitrogen load rate by 30-fold. The CO2 removal slightly increased during the three periods, and permitted the removal of 65% of the influent CO2, which corresponded to an average removal of 2.2 g CO2/Ld. During the operation with the higher nitrogen load rate, the MEC energy consumption, which was simultaneously used for the different operations, was lower than the selected benchmark technologies, i.e., 0.47 kW/N·m3 for CO2 removal and 0.88 kW·h/kg COD for COD oxidation were consumed by the MEC while the ammonium nitrogen recovery consumed 2.3 kW·h/kg N.
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Affiliation(s)
- Lorenzo Cristiani
- Department of Chemistry, University of Rome Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy; (M.Z.); (C.P.); (M.M.)
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Reductive/Oxidative Sequential Bioelectrochemical Process for Perchloroethylene Removal. WATER 2019. [DOI: 10.3390/w11122579] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
An innovative bioelectrochemical reductive/oxidative sequential process was developed and tested on a laboratory scale to obtain the complete mineralization of perchloroethylene (PCE) in a synthetic medium. The sequential bioelectrochemical process consisted of two separate tubular bioelectrochemical reactors that adopted a novel reactor configuration, avoiding the use of an ion exchange membrane to separate the anodic and cathodic chamber and reducing the cost of the reactor. In the reductive reactor, a dechlorinating mixed inoculum received reducing power to perform the reductive dechlorination of perchloroethylene (PCE) through a cathode chamber, while the less chlorinated daughter products were removed in the oxidative reactor, which supported an aerobic dechlorinating culture through in situ electrochemical oxygen evolution. Preliminary fluid dynamics and electrochemical tests were performed to characterize both the reductive and oxidative reactors, which were electrically independent of each other, with each having its own counterelectrode. The first continuous-flow potentiostatic run with the reductive reactor (polarized at −450 mV vs SHE) resulted in obtaining 100% ± 1% removal efficiency of the influent PCE, while the oxidative reactor (polarized at +1.4 V vs SHE) oxidized the vinyl chloride and ethylene from the reductive reactor, with removal efficiencies of 100% ± 2% and 92% ± 1%, respectively.
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