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Yebo Li - One of the best experts on this subject based on the ideXlab platform.
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Challenges and strategies for solid-state Anaerobic Digestion of lignocellulosic biomass
Renewable and Sustainable Energy Reviews, 2015Co-Authors: Liangcheng Yang, Fuqing Xu, Xumeng Ge, Yebo LiAbstract:Solid-state Anaerobic Digestion (SS-AD) has gained increasing attention in recent years, especially for digesting lignocellulosic biomass. Compared to liquid Anaerobic Digestion (L-AD), SS-AD handles feedstocks with higher total solids content, and therefore, performs more effectively at higher organic loading rates and has higher volumetric biogas productivity. Challenges facing SS-AD of lignocellulosic biomass are primarily related to its relatively low methane yield, potential instability, and low value end-products. These challenges are either due to the inherent limits of SS-AD (e.g. retarded mass transfer caused by high solid content) or can be attributed to the nature of lignocellulosic biomass (e.g. components recalcitrant to biodegradation). To address these challenges, a variety of methods, including pretreatment of feedstock, improvement of inoculation efficiency, co-Digestion of multiple feedstocks, and upgrading biogas to higher-value transportation fuels, have been examined to enhance the performance of SS-AD and increase the value of the end products. This review summarizes these challenges in SS-AD of lignocellulosic biomass and discusses the mechanisms and feasibility of potential strategies for resolving them.
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effects of microbial and non microbial factors of liquid Anaerobic Digestion effluent as inoculum on solid state Anaerobic Digestion of corn stover
Bioresource Technology, 2014Co-Authors: Fuqing Xu, Zhongtang Yu, Zhongjiang Wang, Jill A Stiverson, Yebo LiAbstract:The microbial activity of the inoculum (liquid Anaerobic Digestion effluent) was altered by autoclaving part of the effluent to study the effect of feedstock to active effluent ratio (F/Ea, 2.2–6.6) and the feedstock to total effluent ratio (F/Et, 2.2 and 4.4) on reactor performance in solid state Anaerobic Digestion (SS-AD) of corn stover. When the F/Ea ratio was increased from 2.2 to 6.6, methane yield was not significantly reduced; however, reactors became acidified when the F/Et ratio was increased from 2.2 to 4.4. It was concluded that F/Et had a greater effect on methane yields than F/Ea for the range studied in this paper. As analyzed by denaturing gradient gel electrophoresis using PCR amplified 16S rRNA genes, the microbial community underwent dynamic shifts under acidified conditions over 38 days of SS-AD. These shifts reflected the acclimation, both adaptive selection and diversification, of the initial inoculated microbial consortia.
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comparison of different liquid Anaerobic Digestion effluents as inocula and nitrogen sources for solid state batch Anaerobic Digestion of corn stover
Waste Management, 2013Co-Authors: Fuqing Xu, Wen Lv, Zhongtang Yu, Yebo LiAbstract:Highlights: Black-Right-Pointing-Pointer Compared methane production of solid AD inoculated with different effluents. Black-Right-Pointing-Pointer Food waste effluent (FWE) had the largest population of acetoclastic methanogens. Black-Right-Pointing-Pointer Solid AD inoculated with FWE produced the highest methane yield at F/E ratio of 4. Black-Right-Pointing-Pointer Dairy waste effluent (DWE) was rich of cellulolytic and xylanolytic bacteria. Black-Right-Pointing-Pointer Solid AD inoculated with DWE produced the highest methane yield at F/E ratio of 2. - Abstract: Effluents from three liquid Anaerobic digesters, fed with municipal sewage sludge, food waste, or dairy waste, were evaluated as inocula and nitrogen sources for solid-state batch Anaerobic Digestion of corn stover in mesophilic reactors. Three feedstock-to-effluent (F/E) ratios (i.e., 2, 4, and 6) were tested for each effluent. At an F/E ratio of 2, the reactor inoculated by dairy waste effluent achieved the highest methane yield of 238.5 L/kgVS{sub feed}, while at an F/E ratio of 4, the reactor inoculated by food waste effluent achieved the highest methane yield of 199.6 L/kgVS{sub feed}. The microbial population and chemical composition of the three effluents were substantially different. Food waste effluent had the largest population of acetoclastic methanogens, while dairy waste effluent had the largest populations of cellulolytic and xylanolytic bacteria. Dairymore » waste also had the highest C/N ratio of 8.5 and the highest alkalinity of 19.3 g CaCO{sub 3}/kg. The performance of solid-state batch Anaerobic Digestion reactors was closely related to the microbial status in the liquid Anaerobic Digestion effluents.« less
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enhancing the solid state Anaerobic Digestion of fallen leaves through simultaneous alkaline treatment
Bioresource Technology, 2011Co-Authors: Lo Niee Liew, Yebo LiAbstract:Abstract Previous studies have shown that alkali pretreatment prior to Anaerobic Digestion (AD) can increase the digestibility of lignocellulosic biomass and methane yield. In order to simplify the process and reduce the capital cost, simultaneous alkali treatment and Anaerobic Digestion was evaluated for methane production from fallen leaves. The highest methane yield of 82 L/kg volatile solids (VS) was obtained at NaOH loading of 3.5% and substrate-to-inoculum (S/I) ratio of 4.1. The greatest enhancement in methane yield was achieved at S/I ratio of 6.2 with NaOH loading of 3.5% which was 24-fold higher than that of the control (without NaOH addition). Reactors at S/I ratio of 8.2 resulted in failure of the AD process. In addition, increasing the total solid (TS) content from 20% to 26% reduced biogas yield by 35% at S/I ratio of 6.2 and NaOH loading of 3.5%. Cellulose and hemicellulose degradation and methane yields are highly related.
Fuqing Xu - One of the best experts on this subject based on the ideXlab platform.
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Challenges and strategies for solid-state Anaerobic Digestion of lignocellulosic biomass
Renewable and Sustainable Energy Reviews, 2015Co-Authors: Liangcheng Yang, Fuqing Xu, Xumeng Ge, Yebo LiAbstract:Solid-state Anaerobic Digestion (SS-AD) has gained increasing attention in recent years, especially for digesting lignocellulosic biomass. Compared to liquid Anaerobic Digestion (L-AD), SS-AD handles feedstocks with higher total solids content, and therefore, performs more effectively at higher organic loading rates and has higher volumetric biogas productivity. Challenges facing SS-AD of lignocellulosic biomass are primarily related to its relatively low methane yield, potential instability, and low value end-products. These challenges are either due to the inherent limits of SS-AD (e.g. retarded mass transfer caused by high solid content) or can be attributed to the nature of lignocellulosic biomass (e.g. components recalcitrant to biodegradation). To address these challenges, a variety of methods, including pretreatment of feedstock, improvement of inoculation efficiency, co-Digestion of multiple feedstocks, and upgrading biogas to higher-value transportation fuels, have been examined to enhance the performance of SS-AD and increase the value of the end products. This review summarizes these challenges in SS-AD of lignocellulosic biomass and discusses the mechanisms and feasibility of potential strategies for resolving them.
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effects of microbial and non microbial factors of liquid Anaerobic Digestion effluent as inoculum on solid state Anaerobic Digestion of corn stover
Bioresource Technology, 2014Co-Authors: Fuqing Xu, Zhongtang Yu, Zhongjiang Wang, Jill A Stiverson, Yebo LiAbstract:The microbial activity of the inoculum (liquid Anaerobic Digestion effluent) was altered by autoclaving part of the effluent to study the effect of feedstock to active effluent ratio (F/Ea, 2.2–6.6) and the feedstock to total effluent ratio (F/Et, 2.2 and 4.4) on reactor performance in solid state Anaerobic Digestion (SS-AD) of corn stover. When the F/Ea ratio was increased from 2.2 to 6.6, methane yield was not significantly reduced; however, reactors became acidified when the F/Et ratio was increased from 2.2 to 4.4. It was concluded that F/Et had a greater effect on methane yields than F/Ea for the range studied in this paper. As analyzed by denaturing gradient gel electrophoresis using PCR amplified 16S rRNA genes, the microbial community underwent dynamic shifts under acidified conditions over 38 days of SS-AD. These shifts reflected the acclimation, both adaptive selection and diversification, of the initial inoculated microbial consortia.
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comparison of different liquid Anaerobic Digestion effluents as inocula and nitrogen sources for solid state batch Anaerobic Digestion of corn stover
Waste Management, 2013Co-Authors: Fuqing Xu, Wen Lv, Zhongtang Yu, Yebo LiAbstract:Highlights: Black-Right-Pointing-Pointer Compared methane production of solid AD inoculated with different effluents. Black-Right-Pointing-Pointer Food waste effluent (FWE) had the largest population of acetoclastic methanogens. Black-Right-Pointing-Pointer Solid AD inoculated with FWE produced the highest methane yield at F/E ratio of 4. Black-Right-Pointing-Pointer Dairy waste effluent (DWE) was rich of cellulolytic and xylanolytic bacteria. Black-Right-Pointing-Pointer Solid AD inoculated with DWE produced the highest methane yield at F/E ratio of 2. - Abstract: Effluents from three liquid Anaerobic digesters, fed with municipal sewage sludge, food waste, or dairy waste, were evaluated as inocula and nitrogen sources for solid-state batch Anaerobic Digestion of corn stover in mesophilic reactors. Three feedstock-to-effluent (F/E) ratios (i.e., 2, 4, and 6) were tested for each effluent. At an F/E ratio of 2, the reactor inoculated by dairy waste effluent achieved the highest methane yield of 238.5 L/kgVS{sub feed}, while at an F/E ratio of 4, the reactor inoculated by food waste effluent achieved the highest methane yield of 199.6 L/kgVS{sub feed}. The microbial population and chemical composition of the three effluents were substantially different. Food waste effluent had the largest population of acetoclastic methanogens, while dairy waste effluent had the largest populations of cellulolytic and xylanolytic bacteria. Dairymore » waste also had the highest C/N ratio of 8.5 and the highest alkalinity of 19.3 g CaCO{sub 3}/kg. The performance of solid-state batch Anaerobic Digestion reactors was closely related to the microbial status in the liquid Anaerobic Digestion effluents.« less
David P. Chynoweth - One of the best experts on this subject based on the ideXlab platform.
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renewable methane from Anaerobic Digestion of biomass
Renewable Energy, 2001Co-Authors: David P. Chynoweth, John M. Owens, Robe LegrandAbstract:Production of methane via Anaerobic Digestion of energy crops and organic wastes would benefit society by providing a clean fuel from renewable feedstocks. This would replace fossil fuel-derived energy and reduce environmental impacts including global warming and acid rain. Although biomass energy is more costly than fossil fuel-derived energy, trends to limit carbon dioxide and other emissions through emission regulations, carbon taxes, and subsidies of biomass energy would make it cost competitive. Methane derived from Anaerobic Digestion is competitive in efficiencies and costs to other biomass energy forms including heat, synthesis gases, and ethanol.
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Renewable methane from Anaerobic Digestion of biomass
Renewable Energy, 2000Co-Authors: David P. Chynoweth, John M. Owens, Robert LegrandAbstract:Production of methane via Anaerobic Digestion of energy crops and organic wastes would benefit society by providing a clean fuel from renewable feedstocks. This would replace fossil fuel-derived energy and reduce environmental impacts including global warming and acid rain. Although biomass energy is more costly than fossil fuel-derived energy, trends to limit carbon dioxide and other emissions through emission regulations, carbon taxes, and subsidies of biomass energy would make it cost competitive. Methane derived from Anaerobic Digestion is competitive in efficiencies and costs to other biomass energy forms including heat, synthesis gases, and ethanol. (C) 2000 Elsevier Science Ltd. All rights reserved.
Jiying Zhu - One of the best experts on this subject based on the ideXlab platform.
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enhanced solid state Anaerobic Digestion of corn stover by alkaline pretreatment
Bioresource Technology, 2010Co-Authors: Jiying ZhuAbstract:Alkaline pretreatment was applied to enhance biogas production from corn stover through solid-state Anaerobic Digestion. Different NaOH loadings (1%, 2.5%, 5.0% and 7.5% (w/w)) were tested for solid-state pretreatment of corn stover. Lignin degradation during pretreatment increased from 9.1% to 46.2% when NaOH concentration increased from 1.0% to 7.5%. The NaOH-pretreated corn stover was digested using effluent of liquid Anaerobic Digestion as inoculum and nitrogen source. NaOH loading of 1% did not cause significant improvement on biogas yield. The highest biogas yield of 372.4 L/kg VS was obtained with 5% NaOH-pretreated corn stover, which was 37.0% higher than that of the untreated corn stover. However, a higher NaOH loading of 7.5% caused faster production of volatile fatty acids during the hydrolysis and acidogenesis stages, which inhibited the methanogenesis. Simultaneous NaOH treatment and Anaerobic Digestion did not significantly improve the biogas production (P>0.05).
Raf Dewil - One of the best experts on this subject based on the ideXlab platform.
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Anaerobic Digestion in global bio energy production potential and research challenges
Renewable & Sustainable Energy Reviews, 2011Co-Authors: Lise Appels, Joost Lauwers, Jan Degreve, Lieve Helsen, Bart Lievens, Kris Willems, Jan Van Impe, Raf DewilAbstract:It is clear that renewable resources will play a crucial role in limiting the CO2 emissions. Energy from biomass and waste is regarded as one of the most dominant future renewable energy sources, since it can provide a continuous power generation. In this regard, the application of Anaerobic Digestion is emerging spectacularly. This manuscript lists and discusses the main beneficial properties of Anaerobic Digestion. Different types of biomass and waste are suitable for Anaerobic Digestion: the organic fraction of municipal solid waste, waste oils and animal fat, energy crops and agricultural waste, manure and sewage sludge. The potential, opportunities and challenges of these biomasses are discussed. Typical biogas yield and points of attention are included. The manuscript concludes with an overview and discussion of the major research trends in Anaerobic Digestion, including the analysis of microbial community development, the extension of Anaerobic Digestion models, the development of pre-treatment techniques and upgrading of the biogas produced.
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influence of low temperature thermal pre treatment on sludge solubilisation heavy metal release and Anaerobic Digestion
Bioresource Technology, 2010Co-Authors: Lise Appels, Jan Degreve, Bart Van Der Bruggen, Jan Van Impe, Raf DewilAbstract:Abstract In this work, the influence of a low temperature (70–90 °C) thermal treatment on Anaerobic Digestion is studied. Not only the increase in biogas production is investigated, but attention is also paid to the solubilisation of the main organic (proteins, carbohydrates and volatile fatty acids) and inorganic (heavy metals, S and P) sludge constituents during thermal treatment and the breakdown of the organic components during the subsequent Anaerobic Digestion. Taking into account the effects of the treatment on the sludge composition is of prime importance to evaluate its influence on the subsequent Anaerobic Digestion and biogas production using predictive models. It was seen that organic and inorganic compounds are efficiently solubilised during thermal treatment. In general, a higher temperature and a longer treatment time are beneficial for the release. The efficiency of the subsequent Anaerobic Digestion slightly decreased for sludge pre-treated at 70 °C. At higher pre-treatment temperatures, the biogas production increased significantly, up to a factor 11 for the 60 min treatment at 90 °C.
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principles and potential of the Anaerobic Digestion of waste activated sludge
Progress in Energy and Combustion Science, 2008Co-Authors: Lise Appels, Jan Degreve, Jan Baeyens, Raf DewilAbstract:Abstract When treating municipal wastewater, the disposal of sludge is a problem of growing importance, representing up to 50% of the current operating costs of a wastewater treatment plant. Although different disposal routes are possible, Anaerobic Digestion plays an important role for its abilities to further transform organic matter into biogas (60–70 vol% of methane, CH 4 ), as thereby it also reduces the amount of final sludge solids for disposal whilst destroying most of the pathogens present in the sludge and limiting odour problems associated with residual putrescible matter. Anaerobic Digestion thus optimises WWTP costs, its environmental footprint and is considered a major and essential part of a modern WWTP. The potential of using the biogas as energy source has long been widely recognised and current techniques are being developed to upgrade quality and to enhance energy use. The present paper extensively reviews the principles of Anaerobic Digestion, the process parameters and their interaction, the design methods, the biogas utilisation, the possible problems and potential pro-active cures, and the recent developments to reduce the impact of the problems. After having reviewed the basic principles and techniques of the Anaerobic Digestion process, modelling concepts will be assessed to delineate the dominant parameters. Hydrolysis is recognised as rate-limiting step in the complex Digestion process. The microbiology of Anaerobic Digestion is complex and delicate, involving several bacterial groups, each of them having their own optimum working conditions. As will be shown, these groups are sensitive to and possibly inhibited by several process parameters such as pH, alkalinity, concentration of free ammonia, hydrogen, sodium, potassium, heavy metals, volatile fatty acids and others. To accelerate the Digestion and enhance the production of biogas, various pre-treatments can be used to improve the rate-limiting hydrolysis. These treatments include mechanical, thermal, chemical and biological interventions to the feedstock. All pre-treatments result in a lysis or disintegration of sludge cells, thus releasing and solubilising intracellular material into the water phase and transforming refractory organic material into biodegradable species. Possible techniques to upgrade the biogas formed by removing CO 2 , H 2 S and excess moisture will be summarised. Special attention will be paid to the problems associated with siloxanes (SX) possibly present in the sludge and biogas, together with the techniques to either reduce their concentration in sludge by preventive actions such as peroxidation, or eliminate the SX from the biogas by adsorption or other techniques. The reader will finally be guided to extensive publications concerning the operation, control, maintenance and troubleshooting of Anaerobic Digestion plants.
