development and performance analysis of biowaste based microbial fuel cells fabricated employing additive manufacturing technologies

Abstract In this work two different configurations of MFCs are tested, evaluating the importance of the operative conditions on power production. All the MFCs were fabricated employing 3D printing technologies and, by using biocompatible materials as for the body as for the electrodes, are analyzed the point of strength and development needed at the state of the art for this particular application. Power productions and stability in terms of energy production are deepen investigated for both the systems in order to quantify how much power can be extracted from the bacteria when a load is fixed for long time

Use of Biochar-Based Cathodes and Increase in the Electron Flow by Pseudomonas aeruginosa to Improve Waste Treatment in Microbial Fuel Cells

In this paper, we tested the combined use of a biochar-based material at the cathode and of Pseudomonas aeruginosa strain in a single chamber, air cathode microbial fuel cells (MFCs) fed with a mix of shredded vegetable and phosphate buffer solution (PBS) in a 30% solid/liquid ratio. As a control system, we set up and tested MFCs provided with a composite cathode made up of a nickel mesh current collector, activated carbon and a single porous poly tetra fluoro ethylene (PTFE) diffusion layer. At the end of the experiments, we compared the performance of the two systems, in the presence and absence of P. aeruginosa, in terms of electric outputs. We also explored the potential reutilization of cathodes. Unlike composite material, biochar showed a life span of up to 3 cycles of 15 days each, with a pH of the feedstock kept in a range of neutrality. In order to relate the electric performance to the amount of solid substrates used as source of carbon and energy, besides of cathode surface, we referred power density (PD) and current density (CD) to kg of biomass used. The maximum outputs obtained when using the sole microflora were, on average, respectively 0.19 Wm−2kg−1 and 2.67 Wm−2kg−1 , with peaks of 0.32 Wm−2kg−1 and 4.87 Wm−2kg−1 of cathode surface and mass of treated biomass in MFCs with biochar and PTFE cathodes respectively. As to current outputs, the maximum values were 7.5 Am−2 kg−1 and 35.6 Am−2kg−1 in MFCs with biochar-based material and a composite cathode. If compared to the utilization of the sole acidogenic/acetogenic microflora in vegetable residues, we observed an increment of the power outputs of about 16.5 folds in both systems when we added P. aeruginosa to the shredded vegetables. Even though the MFCs with PTFE-cathode achieved the highest performance in terms of PD and CD, they underwent a fouling episode after about 10 days of operation, with a dramatic decrease in pH and both PD and CD. Our results confirm the potentialities of the utilization of biochar-based materials in waste treatment and bioenergy production

performance of two different types of cathodes in microbial fuel cells for power generation from renewable sources

Abstract Microbial fuel cells (MFCs) technology represents a new approach to the sustainable electric power production, thanks to the advantages of its green features. The performance and the cost efficiency of a MFC are affected by several factors, such as the reactor architecture, the microbial microflora and the "costs per power" ratio of the electrodes. For example, cathodes powered by platinum as catalyzer are really efficient, but also expensive. In this study, two materials for cathode were examined: i) an economical biochar-based material (BC), ii) an activated carbon (AC) cathode with a nickel mesh current collector and a polytetrafluoroethylene (PTFE) binder to limit oxygen diffusion to the anodic compartment. The performances were evaluated in terms of power density and current density

On the Emergy accounting for the evaluation of road transport systems: an Italian case study

Road transportation is one of the most polluting as well as energy-intensive sectors, and requires planning policies capable to address at the same time several different environmental, social, and economic issues. Cost-benefit analyses are generally carried out with a major focus on fuelling and driving efficiency, whereas a systemic approach appears to be needed for a more comprehensive evaluation of the alternatives that may become available to address any issue, be it intended for either short-term or long-term spans. For instance, building up a new infrastructure might allow for savings in time or fuel per km, but this may require an equivalent or even higher socio-environmental investment. In this work, a short review is presented of some systemic studies on transportation that use the emergy synthesis methodology. A case study is also addressed, concerning recent important expansion works on the Apennine Mountains section of the Italian major highway A1. In particular, the analysis points out the role of time saving, since for a new or renewed transport infrastructure (and when comparing for example road to rail transport) saved time is likely to become crucial in justifying civil enterprises. Nevertheless, the present emergy synthesis and the teaching of H.T. Odum (Odum & Odum, 2001) warn us that such “luxury” highly depends on the abundance of available energy, which is less and less given for granted, whereas a systemic analysis approach may indicate different levels of criticality when oriented towards environmental and well-being issues

Harvesting Energy Using Compost as a Source of Carbon and Electrogenic Bacteria

Compost is widely used to improve soil fertility for its chemical-physical properties, with particular regard to the abundance of humic substances. Compared to the untreated organic solid waste, the use of compost in Microbial Fuel Cells (MFCs) could offer different advantages like the strong reduction of fermentative processes. The use of compost in MFCs in combination with soil or mixed with other substrates had been reported by some researchers to improve the performance of MFCs fed with agro-industrial residues and plant-MFCs. In this chapter, we report the results of an experiment carried out using a compost of vegetable residues as feedstock in a single chamber, air cathode MFCs. We investigated the behaviour of two MFCs serially connected, the possibility to use compost as a long-term source of energy in MFCs, the influence of cathode surface /cell volume ratio on MFCs performance in terms of power and current density. Our results showed for MFCs serially connected a maximum PD and CD of 234 mW/m 2 and 1.6 A/m 2 respectively, with a maximum OCV of 557 mV. Unexpectedly, the compost-based MFCs kept significant electric outputs (854 mV, 467 mW/m 2 kg and 114 mA/m 2 kg) after being reactivated two years later its setup thus demonstrating its potential as long-term operation energy system

Valorisation of banana peels by hydrothermal carbonisation: Potential use of the hydrochar and liquid by-product for water purification and energy conversion

Banana peels were used as feedstock to produce a carbon dense hydrochar for the removal of toxic metals from wastewater. Compared to the biomass feedstock (41.3% mass C), the banana peel hydrochar possesses higher carbon (54–72% mass C) and lower ash contents. The carbonised banana peels treated between 150 and 300 °C (1−2h) demonstrated an excellent ability to remove Cd2+ (5–100 mg L−1), achieving 99% removal, in comparison with 75% for the raw peel. The liquid by-product generated in the carbonisation process was tested as feedstock in microbial electrochemical devices, showing significant reduction in the chemical oxygen demand levels (initially 10–25 103 mg L−1), associated with the production of electrical outputs; 81–85% reduction with microbial communities from compost, and 53–85% with anaerobic sludge. The results demonstrate the complete utilization of waste from mass cultivation of banana, providing a full-cycle solution for the pollution associated to this important crop.[Display omitted]•Hydrothermal carbonisation is a sustainable solution for waste in banana industry.•Hydrochars from banana peels are effective sorbents of Cd2+ ion from water.•Promising use of liquid by-product from hydrocharring for bioelectrochemical cells

Biohydrogen production from solid phase-microbial fuel cell spent substrate: A preliminary study

Bio-based waste management processes, as anaerobic digestion, couple waste treatment with energy production using natural processes based on microbial metabolism. Microbial fuel cells (MFCs) combine the production of electric power to the lowering the load of waste organic and mineral nutrients. In this study, the coordinated utilization of MFCs with anaerobic digestion in a two-steps process has been investigated. A single chamber, air cathode, membraneless MFCs with graphite plates as electrodes, fed with the organic fraction of municipal waste, was run for 4 weeks. The energy obtained was characterized by a maximum current density of 42.3 mA/m2 kg, a power density of 1.98 mW/m2 kg, and a columbic efficiency ηC ∼5%. pH of the slurry was maintained at 6.8 $pm$ 0.9 along the experiment. MFC spent substrate was then used in a batch experiment for biohydrogen and biomethane production through AD. The biohydrogen increased by 276%, as compared to that produced from the same fresh untreated Organic Fraction of Municipal Solid Waste. A decrease in methane production of 66% was however observed. The analysis of MFC spent substrate revealed the prevalence of Lactobacillaceae, Bacillaceae, Clostridia and Pseudomonadaceae, with Pseudomonas aeruginosa colonizing the cathode

Biohydrogen production from Solid Phase-Microbial Fuel Cell (SPMFC) spent substrate: a preliminary study

Bio-based waste management processes, like Anaerobic Digestion (AD) and Dark Fermentation (DF), couple waste treatment with energy production using natural processes based on microbial metabolism. In addition, Microbial Fuel Cells (MFCs), like other Bio-Electrochemical Systems (BESs), couples the removal of organic load and mineral nutrients with the production of electric power and commodity chemicals. In this study the potential joined utilization of MFCs with AD and DF in a two-steps process has been investigated. Our results show an increase of biohydrogen (276 %) production from MFCs spent substrates in comparison to the untreated solid organic residues from the Organic Fraction of Municipal Solid Waste (OFMSW). MFCs, if adequately improved and scaled up, could merge DF in a more efficient and cost-effective bio-process for a sustainable waste management