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Records with Subject: Biosystems
Showing records 1 to 25 of 59. [First] Page: 1 2 3 Last
The Effect of Two Types of Biochars on the Efficacy, Emission, Degradation, and Adsorption of the Fumigant Methyl Isothiocyanate
Wensheng Fang, Aocheng Cao, Dongdong Yan, Dawei Han, Bin Huang, Jun Li, Xiaoman Liu, Meixia Guo, Qiuxia Wang
March 15, 2019 (v1)
Subject: Biosystems
Keywords: Adsorption, biochar, dazomet, degradation, methyl isothiocyanate (MITC)
Biochar (BC) is increasingly applied in agriculture; however, due to its adsorption and degradation properties, biochar may also affect the efficacy of fumigant in amended soil. Our research is intended to study the effects of two types of biochars (BC-1 and BC-2) on the efficacy and emission of methyl isothiocyanate (MITC) in biochar amendment soil. Both types of biochars can significantly reduce MITC emission losses, but, at the same time, decrease the concentration of MITC in the soil. The efficacy of MITC for controlling soil-borne pests (Meloidogyne spp., Fusarium spp. Phytophthora spp., Abutilon theophrasti and Digitaria sanguinalis) was reduced when the biochar (BC-1 and BC-2) was applied at a rate of higher than 1% and 0.5% (on a weight basis) (on a weight basis), respectively. However, increased doses of dazomet (DZ) were able to offset decreases in the efficacy of MITC in soils amended with biochars. Biochars with strong adsorption capacity (such as BC-1) substantially reduce... [more]
Effect of Air Staging Ratios on the Burning Rate and Emissions in an Underfeed Fixed-Bed Biomass Combustor
Araceli Regueiro, David Patiño, Jacobo Porteiro, Enrique Granada, José Luis Míguez
February 5, 2019 (v1)
Subject: Biosystems
Keywords: air staging, bed stoichiometry, biomass combustion, burning rate, fixed-bed
This experimental work studies a small-scale biomass combustor (5⁻12 kW) with an underfed fixed bed using low air staging ratios (15%⁻30%). This document focuses on the influence of the operative parameters on the combustion process, so gaseous emissions and the distribution and concentration of particulate matter have also been recorded. The facility shows good stability and test repeatability. For the studied airflow ranges, the results show that increasing the total airflow rate does not increase the overall air excess ratio because the burning rate is proportionally enhanced (with some slight differences that depend on the air staging ratio). Consequently, the heterogeneous reactions at the bed remain in the so-called oxygen-limited region, and thus the entire bed operates under sub-stoichiometric conditions with regards of the char content of the biomass. In addition, tests using only primary air (no staging) may increase the fuel consumption, but in a highly incomplete way, appro... [more]
Biomass Residues to Renewable Energy: A Life Cycle Perspective Applied at a Local Scale
Esmeralda Neri, Daniele Cespi, Leonardo Setti, Erica Gombi, Elena Bernardi, Ivano Vassura, Fabrizio Passarini
February 5, 2019 (v1)
Subject: Biosystems
Keywords: energy efficient city, life cycle assessment (LCA), recovery, small community, thermal energy
Italy, like every country member of the European Union (EU), will have to achieve the objectives required by the Energy Roadmap 2050. The purpose of the study was to evaluate the environmental impacts of residue recovery arising from the management of public and private green feedstocks, activity of the cooperative “Green City” in the Bologna district, and usage in a centralized heating system to produce thermal energy for public buildings. Results, obtained using the ReCipe impact assessment method, are compared with scores achieved by a traditional methane boiler. The study shows some advantages of the biomass-based system in terms of greenhouse gases (GHGs) emissions and consumption of non-renewable fuels, which affect climate change (−41%) and fossil resources depletion (−40%), compared to the use of natural gas (NG). Moreover, scores from network analysis denote the great contribution of feedstock transportation (98% of the cumulative impact). The main reason is attributable to al... [more]
A Principal Component Analysis in Switchgrass Chemical Composition
Mario Aboytes-Ojeda, Krystel K. Castillo-Villar, Tun-hsiang E. Yu, Christopher N. Boyer, Burton C. English, James A. Larson, Lindsey M. Kline, Nicole Labbé
February 5, 2019 (v1)
Subject: Biosystems
Keywords: bioenergy, lignocellulosic biomass, principal component analysis, statistical hypothesis, switchgrass
In recent years, bioenergy has become a promising renewable energy source that can potentially reduce the greenhouse emissions and generate economic growth in rural areas. Gaining understanding and controlling biomass chemical composition contributes to an efficient biofuel generation. This paper presents a principal component analysis (PCA) that shows the influence and relevance of selected controllable factors over the chemical composition of switchgrass and, therefore, in the generation of biofuels. The study introduces the following factors: (1) storage days; (2) particle size; (3) wrap type; and (4) weight of the bale. Results show that all the aforementioned factors have an influence in the chemical composition. The number of days that bales have been stored was the most significant factor regarding changes in chemical components due to its effect over principal components 1 and 2 (PC1 and PC2, approximately 80% of the total variance). The storage days are followed by the particl... [more]
Thermal Cracking of Jatropha Oil with Hydrogen to Produce Bio-Fuel Oil
Yi-Yu Wang, Chia-Chi Chang, Ching-Yuan Chang, Yi-Hung Chen, Je-Lueng Shie, Min-Hao Yuan, Yen-Hau Chen, Li-Xuan Huang, Cesar Augusto Andrade-Tacca, Do Van Manh, Min-Yi Tsai, Michael Huang
January 31, 2019 (v1)
Subject: Biosystems
Keywords: bio-fuel oil, cracking, hydrogenation, jatropha oil (JO)
This study used thermal cracking with hydrogen (HTC) to produce bio-fuel oil (BFO) from jatropha oil (JO) and to improve its quality. We conducted HTC with different hydrogen pressures (PH2; 0⁻2.07 MPa or 0⁻300 psig), retention times (tr; 40⁻780 min), and set temperatures (TC; 623⁻683 K). By applying HTC, the oil molecules can be hydrogenated and broken down into smaller molecules. The acid value (AV), iodine value, kinematic viscosity (KV), density, and heating value (HV) of the BFO produced were measured and compared with the prevailing standards for oil to assess its suitability as a substitute for fossil fuels or biofuels. The results indicate that an increase in PH2 tends to increase the AV and KV while decreasing the HV of the BFO. The BFO yield (YBFO) increases with PH2 and tr. The above properties decrease with increasing TC. Upon HTC at 0.69 MPa (100 psig) H₂ pressure, 60 min time, and 683 K temperature, the YBFO was found to be 86 wt%. The resulting BFO possesses simulated di... [more]
Assessment of the Agronomic Feasibility of Bioenergy Crop Cultivation on Marginal and Polluted Land: A GIS-Based Suitability Study from the Sulcis Area, Italy
Giuseppe Pulighe, Guido Bonati, Stefano Fabiani, Tommaso Barsali, Flavio Lupia, Silvia Vanino, Pasquale Nino, Pasquale Arca, Pier Paolo Roggero
January 31, 2019 (v1)
Subject: Biosystems
Keywords: agronomic feasibility, Biomass, geographic information system (GIS), land suitability, marginal land, spatial analysis
In the context of environmental sustainability there has been an increasing interest in bioenergy production from renewable resources, and is expected that European biofuel production from energy crops will increase as a consequence of the achievement of policy targets. The aim of this paper is to assess the agronomic feasibility of biomass crop cultivation to provide profitable renewable feedstocks in a marginal and heavy-metal polluted area located in the Sulcis district, Sardinia (Italy). Results from literature review and unpublished data from field trials carried out in Sardinia were analysed to establish the main agronomic traits of crops (e.g., yield potential and input requirements). A Geographical Information System (GIS)-based procedure with remotely sensed data is also used to evaluate the land suitability and the actual land use/cover, considering a future scenario of expansion of energy crops on these marginal areas avoiding potential conflicts with food production. The re... [more]
Effects of Biochar Amendment on Chloropicrin Adsorption and Degradation in Soil
Pengfei Liu, Qiuxia Wang, Dongdong Yan, Wensheng Fang, Liangang Mao, Dong Wang, Yuan Li, Canbin Ouyang, Meixia Guo, Aocheng Cao
January 31, 2019 (v1)
Subject: Biosystems
Keywords: Adsorption, biochar, chloropicrin, degradation, pyrolysis temperature
The characteristics of biochar vary with pyrolysis temperature. Chloropicrin (CP) is an effective fumigant for controlling soil-borne pests. This study investigated the characteristics of biochars prepared at 300, 500, and 700 °C by michelia alba (Magnolia denudata) wood and evaluated their capacity to adsorb CP. The study also determined the potential influence of biochar, which was added to sterilized and unsterilized soils at rates of 0%, 1%, 5%, and 100%, on CP degradation. The specific surface area, pore volume, and micropores increased considerably with an increase in the pyrolytic temperature. The adsorption rate of biochar for CP increased with increasing pyrolytic temperature. The maximum adsorption amounts of CP were similar for the three biochars. Next, the study examined the degradation ability of the biochar for CP. The degradation rate constant (k) of CP increased when biochar was added to the soil, and k increased with increased amendment rate and pyrolysis temperature.... [more]
Lignocellulosic Ethanol Production from the Recovery of Stranded Driftwood Residues
Gianluca Cavalaglio, Mattia Gelosia, Silvia D’Antonio, Andrea Nicolini, Anna Laura Pisello, Marco Barbanera, Franco Cotana
January 30, 2019 (v1)
Subject: Biosystems
Keywords: bioethanol, cellulose hydrolysis, steam explosion, stranded driftwood residues
This paper builds upon a research project funded by the Italian Ministry of Environment, and aims to recover stranded driftwood residues (SDRs), in order to transform a potential pollution and safety issue into valuable bio-resources. In particular, one of the experiments consisted of bioethanol production from lignocellulosic residues. The SDRs were gathered from the Italian coast (Abruzzo Region, Italy) after an intense storm. The biomass recalcitrance, due to its lignocellulosic structure, was reduced by a steam explosion (SE) pretreatment process. Four different pretreatment severity factors (R₀) were tested (LogR₀ 3.65, 4.05, 4.24 and 4.64) in order to evaluate the pretreated material’s accessibility to enzymatic attack and the holocellulose (cellulose plus hemicellulose) recovery. A first enzymatic hydrolysis was performed on the pretreated materials by employing a solid/liquid (S/L) ratio of 1% (w/w) and an enzyme dosage of 30% (w enzyme/w cellulose), in order to estimate the ma... [more]
An Innovative Agro-Forestry Supply Chain for Residual Biomass: Physicochemical Characterisation of Biochar from Olive and Hazelnut Pellets
Ilaria Zambon, Fabrizio Colosimo, Danilo Monarca, Massimo Cecchini, Francesco Gallucci, Andrea Rosario Proto, Richard Lord, Andrea Colantoni
January 7, 2019 (v1)
Subject: Biosystems
Keywords: biochar, Biomass, hazelnut, olive, soil fertiliser
Concerns about climate change and food productivity have spurred interest in biochar, a form of charred organic material typically used in agriculture to improve soil productivity and as a means of carbon sequestration. An innovative approach in agriculture is the use of agro-forestry waste for the production of soil fertilisers for agricultural purposes and as a source of energy. A common agricultural practice is to burn crop residues in the field to produce ashes that can be used as soil fertilisers. This approach is able to supply plants with certain nutrients, such as Ca, K, Mg, Na, B, S, and Mo. However, the low concentration of N and P in the ashes, together with the occasional presence of heavy metals (Ni, Pb, Cd, Se, Al, etc.), has a negative effect on soil and, therefore, crop productivity. This work describes the opportunity to create an innovative supply chain from agricultural waste biomass. Olive (Olea europaea) and hazelnut (Corylus avellana) pruning residues represent a... [more]
Model for Energy Analysis of Miscanthus Production and Transportation
Alessandro Sopegno, Efthymios Rodias, Dionysis Bochtis, Patrizia Busato, Remigio Berruto, Valter Boero, Claus Sørensen
November 28, 2018 (v1)
Subject: Biosystems
Keywords: Biomass, biomass logistics, operations analysis
A computational tool is developed for the estimation of the energy requirements of Miscanthus x giganteus on individual fields that includes a detailed analysis and account of the involved in-field and transport operations. The tool takes into account all the individual involved in-field and transport operations and provides a detailed analysis on the energy requirements of the components that contribute to the energy input. A basic scenario was implemented to demonstrate the capabilities of the tool. Specifically, the variability of the energy requirements as a function of field area and field-storage distance changes was shown. The field-storage distance highly affects the energy requirements resulting in a variation in the efficiency if energy (output/input ratio) from 15.8 up to 23.7 for the targeted cases. Not only the field-distance highly affects the energy requirements but also the biomass transportation system. Based on the presented example, different transportation systems a... [more]
Cathode Assessment for Maximizing Current Generation in Microbial Fuel Cells Utilizing Bioethanol Effluent as Substrate
Guotao Sun, Anders Thygesen, Anne S. Meyer
November 27, 2018 (v1)
Subject: Biosystems
Keywords: air cathode (AiC), bioethanol effluent, dissolved oxygen cathode (DOC), electrochemical impedance spectroscopy (EIS), ferricyanide cathode (FeC)
Implementation of microbial fuel cells (MFCs) for electricity production requires effective current generation from waste products via robust cathode reduction. Three cathode types using dissolved oxygen cathodes (DOCs), ferricyanide cathodes (FeCs) and air cathodes (AiCs) were therefore assessed using bioethanol effluent, containing 20.5 g/L xylose, 1.8 g/L arabinose and 2.5 g/L propionic acid. In each set-up the anode and cathode had an electrode surface area of 88 cm², which was used for calculation of the current density. Electricity generation was evaluated by quantifying current responses to substrate loading rates and external resistance. At the lowest external resistance of 27 Ω and highest substrate loading rate of 2 g chemical oxygen demand (COD) per L·day, FeC-MFC generated highest average current density (1630 mA/m²) followed by AiC-MFC (802 mA/m²) and DOC-MFC (184 mA/m²). Electrochemical impedance spectroscopy (EIS) was used to determine the impedance of the cathodes. It w... [more]
Assessment of the Variability of Biogas Production from Sugar Beet Silage as Affected by Movement and Loss of the Produced Alcohols and Organic Acids
Ali Heidarzadeh Vazifehkhoran, Jin Mi Triolo, Søren Ugilt Larsen, Kasper Stefanek, Sven G. Sommer
November 27, 2018 (v1)
Subject: Biosystems
Keywords: anaerobic digestion, Beta vulgaris, biomethanation, ensiling, organic components, Renewable and Sustainable Energy
The biochemical methane potential and composition of sugar beet pulp silage were investigated using samples taken from six different depths in both open and closed silos (height 3.6 m). The biochemical methane potential (BMP) of pulp silage in open silos ranged from 337 to 420 normal litre (NL) CH₄/kg volatile solids (VS), while the BMP of pulp silage in closed silos varied between 411 and 451 NL CH₄/kg VS. The biochemical methane potential peaked at a depth of 1.45 m with 420 NL CH₄/kg VS for open silos and 451 NL CH₄/kg VS for closed silos. The ethanol concentration and biochemical methane potential showed the same trend with depth throughout the silos. The energy loss correlated to the loss of volatile solids, and the depths described a linear relationship between them for both the open and closed silos (R² = 0.997 for the open silo and R² = 0.991 for the closed silo). The energy potentials and composition of beet pulp silage were highly stratified and there was a risk that the sila... [more]
Techno-Economic Analysis of Integrating First and Second-Generation Ethanol Production Using Filamentous Fungi: An Industrial Case Study
Karthik Rajendran, Sreevathsava Rajoli, Mohammad J. Taherzadeh
November 27, 2018 (v1)
Subject: Biosystems
Keywords: Ethanol, lignocelluloses, process design, process integration, Technoeconomic Analysis
The 2nd generation plants producing ethanol from lignocelluloses demand risky and high investment costs. This paper presents the energy- and economical evaluations for integrating lignocellulose in current 1st generation dry mill ethanol processes, using filamentous fungi. Dry mills use grains and have mills, liquefactions, saccharifications, fermentation, and distillation to produce ethanol, while their stillage passes centrifugation, and evaporation to recycle the water and dry the cake and evaporated syrup into animal feed. In this work, a bioreactor was considered to cultivate fungi on the stillage either before or after the centrifugation step together with pretreated lignocellulosic wheat bran. The results showed that the integrated 1st and 2nd generation ethanol process requires a capital investment of 77 million USD, which could yield NPV of 162 million USD after 20 years. Compared to the fungal cultivation on thin stillage modified 1st generation process, the integrated proces... [more]
Foliage and Grass as Fuel Pellets⁻Small Scale Combustion of Washed and Mechanically Leached Biomass
Jan Hari Arti Khalsa, Frank Döhling, Florian Berger
November 27, 2018 (v1)
Subject: Biosystems
Keywords: combustion, emission reduction, mechanical leaching, residue biomass, solid biofuel
The high contents of disadvantageous elements contained in non-woody biomass are known to cause problems during small and large scale combustion, typically resulting in a higher risk of slagging, corrosion, and increased emissions. Mechanically leaching the respective elements from the biomass through a sequence of process steps has proven to be a promising solution.The florafuel process used here is comprised of size reduction followed by washing and subsequent mechanical dewatering of the biomass. Densification of the upgraded biomass into standardized pellets (Ø 6mm) enables an application in existing small-scale boilers. The presented combustion trials investigated the performance of pellets made from leached grass, foliage and a mixture of both in two small-scale boilers (<100 kWth) with slightly different technology (moving grate versus water-cooled burner tube) during a 4-h measurement period. Emissions were in accordance with German emissions standards except for NOx (thresh... [more]
Modeling of Production and Quality of Bioethanol Obtained from Sugarcane Fermentation Using Direct Dissolved Sugars Measurements
Borja Velazquez-Marti, Sergio Pérez-Pacheco, Juan Gaibor-Chávez, Paola Wilcaso
November 27, 2018 (v1)
Subject: Biosystems
Keywords: bioenergy, biofuel, developing sectors, kinetics model
Bioethanol production from sugarcane represents an opportunity for urban-agricultural development in small communities of Ecuador. Despite the fact that the industry for bioethanol production from sugarcane in Brazil is fully developed, it is still considered expensive as a small rural business. In order to be able to reduce the costs of monitoring the production process, and avoid the application of expensive sensors, the aim of this research was modeling the kinetics of production of bioethanol based on direct measurements of Brix grades, instead of the concentration of alcohol, during the process of cane juice bio-fermentation with Saccharomyces cerevisiae. This avoids the application of expensive sensors that increase the investment costs. Fermentation experiments with three concentrations of yeast and two temperatures were carried out in a laboratory reactor. In each case Brix grades, amount of ethanol and alcoholic degree were measured. A mathematical model to predict the quality... [more]
Ethanol Production from Sweet Sorghum Juice at High Temperatures Using a Newly Isolated Thermotolerant Yeast Saccharomyces cerevisiae DBKKU Y-53
Sunan Nuanpeng, Sudarat Thanonkeo, Mamoru Yamada, Pornthap Thanonkeo
November 27, 2018 (v1)
Subject: Biosystems
Keywords: gene expression, high temperature fermentation, real-time RT-PCR, Saccharomyces cerevisiae, sweet sorghum, thermotolerant yeast
Ethanol production at elevated temperatures requires high potential thermotolerant ethanol-producing yeast. In this study, nine isolates of thermotolerant yeasts capable of growth and ethanol production at high temperatures were successfully isolated. Among these isolates, the newly isolated thermotolerant yeast strain, which was designated as Saccharomyces cerevisiae DBKKU Y-53, exhibited great potential for ethanol production from sweet sorghum juice (SSJ) at high temperatures. The maximum ethanol concentrations produced by this newly isolated thermotolerant yeast at 37 °C and 40 °C under the optimum cultural condition were 106.82 g·L−1 and 85.01 g·L−1, respectively, which are greater than values reported in the literatures. It should be noted from this study with SSJ at a sugar concentration of 250 g·L−1 and an initial pH of 5.5 without nitrogen supplementation can be used directly as substrate for ethanol production at high temperatures by thermotolerant yeast S. cerevisiae DBKKU Y... [more]
Biochar as Additive in Biogas-Production from Bio-Waste
Daniel Meyer-Kohlstock, Thomas Haupt, Erik Heldt, Nils Heldt, Eckhard Kraft
November 27, 2018 (v1)
Subject: Biosystems
Keywords: anaerobic digestion, bio-waste, biochar, biogas, composting, solid-state fermentation
Previous publications about biochar in anaerobic digestion show encouraging results with regard to increased biogas yields. This work investigates such effects in a solid-state fermentation of bio-waste. Unlike in previous trials, the influence of biochar is tested with a setup that simulates an industrial-scale biogas plant. Both the biogas and the methane yield increased around 5% with a biochar addition of 5%—based on organic dry matter biochar to bio-waste. An addition of 10% increased the yield by around 3%. While scaling effects prohibit a simple transfer of the results to industrial-scale plants, and although the certainty of the results is reduced by the heterogeneity of the bio-waste, further research in this direction seems promising.
Integration of Microalgae-Based Bioenergy Production into a Petrochemical Complex: Techno-Economic Assessment
Ana L. Gonçalves, Maria C. M. Alvim-Ferraz, Fernando G. Martins, Manuel Simões, José C. M. Pires
November 27, 2018 (v1)
Subject: Biosystems
Keywords: algal fuels, bioenergy, Carbon Dioxide Capture, microalgal culture, Renewable and Sustainable Energy, wastewater treatment
The rapid development of modern society has resulted in an increased demand for energy, mainly from fossil fuels. The use of this source of energy has led to the accumulation of carbon dioxide (CO₂) in the atmosphere. In this context, microalgae culturing may be an effective solution to reduce the CO₂ concentration in the atmosphere, since these microorganisms can capture CO₂ and, simultaneously, produce bioenergy. This work consists of a techno-economic assessment of a microalgal production facility integrated in a petrochemical complex, in which established infrastructure allows efficient material and energy transport. Seven different scenarios were considered regarding photosynthetic, lipids extraction and anaerobic digestion efficiencies. This analysis has demonstrated six economically viable scenarios able to: (i) reduce CO₂ emissions from a thermoelectric power plant; (ii) treat domestic wastewaters (which were used as culture medium); and (iii) produce lipids and electrical and... [more]
Quantifying the Impact of Feedstock Quality on the Design of Bioenergy Supply Chain Networks
Krystel K. Castillo-Villar, Hertwin Minor-Popocatl, Erin Webb
November 27, 2018 (v1)
Subject: Biosystems
Keywords: bioenergy, bioethanol, Biomass, logging residues, logistics, Optimization, quality costing, supply chain network design
Logging residues, which refer to the unused portions of trees cut during logging, are important sources of biomass for the emerging biofuel industry and are critical feedstocks for the first-type biofuel facilities (e.g., corn-ethanol facilities). Logging residues are under-utilized sources of biomass for energetic purposes. To support the scaling-up of the bioenergy industry, it is essential to design cost-effective biofuel supply chains that not only minimize costs, but also consider the biomass quality characteristics. The biomass quality is heavily dependent upon the moisture and the ash contents. Ignoring the biomass quality characteristics and its intrinsic costs may yield substantial economic losses that will only be discovered after operations at a biorefinery have begun. This paper proposes a novel bioenergy supply chain network design model that minimizes operational costs and includes the biomass quality-related costs. The proposed model is unique in the sense that it suppor... [more]
Evaluation of Cell Disruption of Chlorella Vulgaris by Pressure-Assisted Ozonation and Ultrasonication
Yuanxing Huang, Shengnan Qin, Daofang Zhang, Liang Li, Yan Mu
November 27, 2018 (v1)
Subject: Biosystems
Keywords: cell disrupture, Chlorella vulgaris (C. vulgaris), pressure-assisted ozonation (PAO), quantitative evaluation, ultrasonication (US)
This study evaluated the effectiveness of pressure-assisted ozonation (PAO) in Chlorella vulgaris (C. vulgaris) cell disruption, and compared the disruption result with that of the ultrasonication (US) by using four quantification indicators: cell counting, ultra violet (UV) absorbance, turbidity and visible light absorbance. It was found that under the condition of 0.8 MPa and 80 cycles, PAO treatment achieved cell rupture of 80.3%, with the power of 1080 W and treatment time of 60 min, US achieved cell rupture of 83.8%. Cell counting was a reliable indicator and applicable to both PAO and US treatments. Turbidity and visible light absorbance gave similar results and featured as the simplest operation. UV absorbance reflected the metabolite release due to cell breakage; however, it was less reproducible when it was applied to quantify the cell rupture by PAO. Its trend indicated that during cell disruption metabolite degradation occurred, especially after significant rupture in the ca... [more]
The Environmental Biorefinery: Using Microalgae to Remediate Wastewater, a Win-Win Paradigm
Florian Delrue, Pablo David Álvarez-Díaz, Sophie Fon-Sing, Gatien Fleury, Jean-François Sassi
November 27, 2018 (v1)
Subject: Biosystems
Keywords: biofuel, bioremediation, microalgae, wastewater treatment, water and nutrient recycling
Microalgae have been shown to be a source of multiple bio-based products ranging from high value molecules to commodities. Along with their potential to produce a large variety of products, microalgae can also be used for the depollution of wastewaters of different origins (urban, industrial, and agricultural). This paper is focused on the importance of harnessing the bioremediation capacity of microalgae to treat wastewaters in order to develop the microalgae industry (especially the microalgae biofuel industry) and to find other alternatives to the classic wastewater treatment processes. The current research on the potential of microalgae to treat a specific wastewater or a targeted pollutant is reviewed and discussed. Then, both strategies of selecting the best microalgae strain to treat a specific wastewater or pollutant and using a natural or an artificial consortium to perform the treatment will be detailed. The process options for treating wastewaters using microalgae will be di... [more]
Potential Biogas Production from Artichoke Byproducts in Sardinia, Italy
Fabio De Menna, Remo Alessio Malagnino, Matteo Vittuari, Giovanni Molari, Giovanna Seddaiu, Paola A. Deligios, Stefania Solinas, Luigi Ledda
November 16, 2018 (v1)
Subject: Biosystems
Keywords: artichoke, biogas, byproducts, Sardinia
The paper aims at evaluating the potential biogas production, both in terms of CH₄ and theoretical energy potential, from globe artichoke agricultural byproducts in Sardinia. Field data about the productivity of byproducts were collected on five artichoke varieties cultivated in Sardinia, to assess the biomethane production of their aboveground non-food parts (excluding the head). Moreover, secondary data from previous studies and surveys at regional scale were collected to evaluate the potential biogas production of the different districts. Fresh globe artichoke residues yielded, on average, 292.2 Nm³·tDOM−1, with dissimilarities among cultivars. Fresh samples were analyzed in two series: (a) wet basis; and (b) wet basis with catalytic enzymes application. Enzymes proved to have some beneficial effects in terms of anticipated biomethane availability. At the regional level, ab. 20 × 10⁶ Nm³ CH₄ could be produced, corresponding to the 60% of current installed capacity. However, district... [more]
Systematic Study of Separators in Air-Breathing Flat-Plate Microbial Fuel Cells—Part 2: Numerical Modeling
Sona Kazemi, Melissa Barazandegan, Madjid Mohseni, Khalid Fatih
November 16, 2018 (v1)
Subject: Biosystems
Keywords: crossover, electrode spacing, flat-plate microbial fuel cell (FPMFC), mixed potential theory, numerical model, passive air-breathing, separator
The separator plays a key role on the performance of passive air-breathing flat-plate MFCs (FPMFC) as it isolates the anaerobic anode from the air-breathing cathode. The goal of the present work was to study the separator characteristics and its effect on the performance of passive air-breathing FPMFCs. This was performed partially through characterization of structure, properties, and performance correlations of eight separators presented in Part 1. Current work (Part 2) presents a numerical model developed based on the mixed potential theory to investigate the sensitivity of the electrode potentials and the power output to the separator characteristics. According to this numerical model, the decreased peak power results from an increase in the mass transfer coefficients of oxygen and ethanol, but mainly increasing mixed potentials at the anode by oxygen crossover. The model also indicates that the peak power is affected by the proton transport number of the separator, which affects t... [more]
A Systematic Study of Separators in Air-Breathing Flat-Plate Microbial Fuel Cells—Part 1: Structure, Properties, and Performance Correlations
Sona Kazemi, Madjid Mohseni, Khalid Fatih
November 16, 2018 (v1)
Subject: Biosystems
Keywords: crossover, electrode spacing, flat-plate microbial fuel cell, passive air-breathing, separator
Passive air-breathing microbial fuel cells (MFCs) are a promising technology for energy recovery from wastewater and their performance is highly dependent on characteristics of the separator that isolates the anaerobic anode from the air-breathing cathode. The goal of the present work is to systematically study the separator characteristics and its effect on the performance of passive air-breathing flat-plate MFCs (FPMFCs). This was performed through characterization of structure, properties, and performance correlations of eight separators in Part 1 of this work. Eight commercial separators were characterized, in non-inoculated and inoculated setups, and were examined in passive air-breathing FPMFCs with different electrode spacing. The results showed a decrease in the peak power density as the oxygen and ethanol mass transfer coefficients in the separators increased, due to the increase of mixed potentials especially at smaller electrode spacing. Increasing the electrode spacing was... [more]
A Viable Electrode Material for Use in Microbial Fuel Cells for Tropical Regions
Felix Offei, Anders Thygesen, Moses Mensah, Kwame Tabbicca, Dinesh Fernando, Irina Petrushina, Geoffrey Daniel
October 23, 2018 (v1)
Subject: Biosystems
Keywords: activated carbon, maximum power density, nanowires, palm kernel shells
Electrode materials are critical for microbial fuel cells (MFC) since they influence the construction and operational costs. This study introduces a simple and efficient electrode material in the form of palm kernel shell activated carbon (AC) obtained in tropical regions. The novel introduction of this material is also targeted at introducing an inexpensive and durable electrode material, which can be produced in rural communities to improve the viability of MFCs. The maximum voltage and power density obtained (under 1000 Ω load) using an H-shaped MFC with AC as both anode and cathode electrode material was 0.66 V and 1.74 W/m³, respectively. The power generated by AC was as high as 86% of the value obtained with the extensively used carbon paper. Scanning electron microscopy and Denaturing Gradient Gel Electrophoresis (DGGE) analysis of AC anode biofilms confirmed that electrogenic bacteria were present on the electrode surface for substrate oxidation and the formation of nanowires.
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