Piles à combustible microbiennes pour la production d'électricité couplée au traitement des eaux de l'industrie papetière

L objectif de la thèse est d évaluer la faisabilité de la technologie de pile à combustible microbienne pour la production d électricité couplée au traitement d effluents de l industrie papetière. La première partie du travail montre que de nombreux effluents papetiers permettent de former des biofilms anodiques efficaces. Lorsque les effluents sont complémentés en acétate et l anode polarisée à -0,3V/ECS des densités de courant de 12 A/m et des rendements faradiques de 90% ont été obtenus. Lorsque les effluents sont utilisés comme seuls substrats, les densités de courant atteignent 6 A/m et les rendements faradiques 30%, avec des abattements de DCO jusqu à 50%. Les biofilms anodiques optimaux ont été associées à des cathodes à air abiotiques pour concevoir des piles complètes. Des puissances surfaciques de 294 mW/m à 596 mW/m ont été obtenues avec deux effluents différents.The objective of this thesis was to assess the feasibility of the microbial fuel cell technology for the production of electrical energy coupled with the treatment of pulp and paper effluents. The first part of work showed that various pulp and paper effluents are suitable to form efficient anodic biofilms. When the effluent was supplemented with acetate and the anode polarized between at -0.3 V/SCE, current densities of 12 A/m and Coulombic efficiencies up to 90% were obtained. When effluents were provided as the sole substrate, current densities reached 6 A/m and Coulombic efficiencies 30%, with COD removal around 50%. The optimal anodic biofilms were associated with associated with abiotic air cathodes to design complete microbial fuel cells. Power densities from 294 mW/m to 596 mW/m were obtained with two different effluents.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Stainless steel foam increases the current produced by microbial bioanodes in bioelectrochemical systems

Stainless steel is gaining increasing interest as an anodic material in bioelectrochemical systems and beginning to challenge the more conventional carbon-based materials. Here, microbial bioanodes designed under optimal conditions on carbon cloths gave high current densities, 33.5 + 4.5 A m−2 at −0.2 V/SCE, which were largely outstripped by the current densities of 60 to 80 A m−2 at the same potential and more than 100 A m−2 at 0.0 V/SCE provided by using stainless steel foams

Lowering the applied potential during successive scratching/re-inoculation improves the performance of microbial anodes for microbial fuel cells

Microbial anodes were formed under polarisation at -0.2 V/SCE on smooth graphite plate electrodes with paper mill effluents. Primary, secondary and tertiary biofilms were formed by a successive scratching and re-inoculation procedure. The secondary and tertiary biofilms formed while decreasing the polarisation potential allowed the anodes to provide current density of 6 A/m² at -0.4 V/SCE. In contrast, applying -0.4 V/SCE initially to form the primary biofilms did not lead to the production of current. Consequently, the scratching/re-inoculation procedure combined with progressive lowering of the applied potential revealed an efficient new procedure that gave efficient microbial anodes able to work at low potential. The observed progressive pH drift to alkaline values above 9 explained the open circuit potentials as low as -0.6 V/SCE. The remarkable performance of the electrode at alkaline pH was attributed to the presence of Desulfuromonas acetexigens as the single dominant species in the tertiary microbial anodes

Lowering the applied potential during successive scratching/re-inoculation improves the performance of microbial anodes for microbial fuel cells

Microbial anodes were formed under polarisation at -0.2 V/SCE on smooth graphite plate electrodes with paper mill effluents. Primary, secondary and tertiary biofilms were formed by a successive scratching and re-inoculation procedure. The secondary and tertiary biofilms formed while decreasing the polarisation potential allowed the anodes to provide current density of 6 A/m² at -0.4 V/SCE. In contrast, applying -0.4 V/SCE initially to form the primary biofilms did not lead to the production of current. Consequently, the scratching/re-inoculation procedure combined with progressive lowering of the applied potential revealed an efficient new procedure that gave efficient microbial anodes able to work at low potential. The observed progressive pH drift to alkaline values above 9 explained the open circuit potentials as low as -0.6 V/SCE. The remarkable performance of the electrode at alkaline pH was attributed to the presence of Desulfuromonas acetexigens as the single dominant species in the tertiary microbial anodes

Sampling location of the inoculum is crucial in designing anodes for microbial fuel cells

A Kraft pulp mill effluent was used as the inoculum to form microbial bioanodes under controlled potential at +0.4 V/SCE. Samples were collected at the inlet and outlet of the aerated lagoon of the treatment line. The outlet sample allowed efficient bioanodes to be designed (5.1 A/m²), which included Geobacter and Desulfuromonas sp. in their microbial community. In contrast, the bioanodes formed with the inlet sample did not contain directly connecting anode-respiring bacteria and led to lower currents. It was necessary to reform this bioanode at lower applied potential (-0.2 V/SCE) to select more efficient electroactive species and increase the current density to 5 A/m²

Experimental and theoretical characterization of microbial bioanodes formed in pulp and paper mill effluent in electrochemically controlled conditions

Microbial bioanodes were formed in pulp and paper effluent on graphite plate electrodes under constant polarization at -0.3 V/SCE, without any addition of nutriment or substrate. The bioanodes were characterized in 3-electrode set-ups, in continuous mode, with hydraulic retention times from 6 to 48 h and inlet COD from 500 to 5200 mg/L. Current densities around 4 A/m2 were obtained and voltammetry curves indicated that 6 A/m2 could be reached at +0.1 V/SCE. A theoretical model was designed, which allowed the effects of HRT and COD to be distinguished in the complex experimental data obtained with concomitant variations of the two parameters. COD removal due to the electrochemical process was proportional to the hydraulic retention time and obeyed a Michaelis–Menten law with respect to the COD of the outlet flow, with a Michaelis constant KCOD of 400 mg/L. An inhibition effect occurred above inlet COD of around 3000 mg/L

Microbial electrolysis cell (MEC): A step ahead towards hydrogen-evolving cathode operated at high current density

A microbial electrolysis cell (MEC) 6 L in volume was designed with the objective of maximizing the current density at the cathode. The highly saline electrolyte (NaCl 45 g·L−1) led to a low ohmic resistance, of 0.10 Ω, and made it possible to maintain current density of around 50 A·m−2 for weeks, with peak values up to 90 A·m−2 for hours. This was the highest current density reached in a MEC prototype so far. The gas outlet contained at least 66% H2, which gave a hydrogen flow rate up to 650 Ld−1 m−2 of cathode surface area. The energy and thermal yields were discussed. A numerical mass balance model was designed, which explained the value of the anode Faradaic yield above 100% and pointed out new issues related to high current density operation. In particular, it was shown that, at high current density, carbonate deposit can impact the gas composition

Forming microbial anodes with acetate addition decreases their capability to treat raw paper mill effluent

Microbial anodes were formed under polarization at −0.3 V/SCE on graphite plates in effluents from a pulp and paper mill. The bioanodes formed with the addition of acetate led to the highest current densities (up to 6 A/m2) but were then unable to oxidize the raw effluent efficiently (0.5 A/m2). In contrast, the bioanodes formed without acetate addition were fully able to oxidize the organic matter contained in the effluent, giving up to 4.5 A/m2 in continuous mode. Bacterial communities showed less bacterial diversity for the acetate-fed bioanodes compared to those formed in raw effluents. Deltaproteobacteria were the most abundant taxonomic group, with a high diversity for bioanodes formed without acetate addition but with almost 100% Desulfuromonas for the acetate-fed bioanodes. The addition of acetate to form the microbial anodes induced microbial selection, which was detrimental to the treatment of the raw effluent

Microbial fuel cells: From fundamentals to applications. A review

© 2017 The Author(s) In the past 10–15 years, the microbial fuel cell (MFC) technology has captured the attention of the scientific community for the possibility of transforming organic waste directly into electricity through microbially catalyzed anodic, and microbial/enzymatic/abiotic cathodic electrochemical reactions. In this review, several aspects of the technology are considered. Firstly, a brief history of abiotic to biological fuel cells and subsequently, microbial fuel cells is presented. Secondly, the development of the concept of microbial fuel cell into a wider range of derivative technologies, called bioelectrochemical systems, is described introducing briefly microbial electrolysis cells, microbial desalination cells and microbial electrosynthesis cells. The focus is then shifted to electroactive biofilms and electron transfer mechanisms involved with solid electrodes. Carbonaceous and metallic anode materials are then introduced, followed by an explanation of the electro catalysis of the oxygen reduction reaction and its behavior in neutral media, from recent studies. Cathode catalysts based on carbonaceous, platinum-group metal and platinum-group-metal-free materials are presented, along with membrane materials with a view to future directions. Finally, microbial fuel cell practical implementation, through the utilization of energy output for practical applications, is described