Showing papers on "Biogas published in 2009"
TL;DR: In this article, the authors present some guidelines for biomethane potential assays prepared by the Task Group for the Anaerobic Biodegradation, Activity and Inhibition Assays of the International Water Association.
1,606 citations
TL;DR: Intensive animal production areas need suitable manure management, aiming to export and to redistribute the excess of nutrients from manure and to optimize their recycling, to avoid over-fertilization.
1,466 citations
TL;DR: The ability of these CO2 consuming microalgae to purify biogas and concentrate methane is discussed, and anaerobic digestion of the whole biomass appears to be the optimal strategy on an energy balance basis for the energetic recovery of cell biomass.
1,153 citations
TL;DR: Evaluation of six different wheat straw-to-biofuel production scenaria showed that either use of wheat straw for biogas production or multi-fuel production were the energetically most efficient processes compared to production of mono-fuel such as bioethanol when fermenting C6 sugars alone.
683 citations
TL;DR: A review of the state-of-the-art in biogas purification can be found in this paper, where both mature, already-applied and promising, under-development technologies are reported and described.
Abstract: Biogas is a valuable renewable energy carrier. It can be exploited directly as a fuel or as a raw material for the production of synthesis gas and/or hydrogen. Methane (CH4) and carbon dioxide (CO2) are the main constituents, but biogases also contain significant quantities of undesirable compounds (contaminants), such as hydrogen sulfide (H2S), ammonia (NH3) and siloxanes. The existence and quantities of these contaminants depend on the biogas source (i.e., landfills, anaerobic fermentation of manure). Their presence constitutes a major problem because (i) they can be detrimental to any biogas thermal or thermocatalytic conversion device (e.g., corrosion, erosion, fouling); and (ii) they generate harmful environmental emissions. It is therefore important to include biogas purification steps upstream of its final use processes. This review is aimed at presenting the scientific and technical state-of-theart in biogas purification processes. Both mature, already-applied and promising, under-development technologies are reported and described here. © 2008 Society of Chemical Industry and John Wiley & Sons, Ltd
609 citations
TL;DR: In this article, a Life Cycle Assessment (LCA) of four waste management strategies: landfill without biogas utilization, landfill with biOGAS combustion to generate electricity, sorting plant which splits the inorganic waste fraction (used to produce electricity via Refuse Derived Fuels, RDF) from the organic waste fraction, used to produce bio-diesel via anaerobic digestion, direct incineration of waste, and these scenarios are applied to the waste amount and composition of the Municipality of Roma (Italy).
558 citations
TL;DR: The 16S rRNA gene clone library demonstrated that Clostridia, beta-Proteobacteria, and Bacteroidetes were the dominant microbial community when the current anaerobic fermentation system was operated at pH 8.0, which resulted in the greatest propionic acid content in the fermentative VFAs.
Abstract: Volatile fatty acids (VFAs), the carbon source of biological nutrients removal, can be produced by waste activated sludge (WAS) anaerobic fermentation. However, because of high protein content and low carbon to nitrogen mass ratio (C/N) of WAS, the production of VFAs, especially propionic acid, a more preferred VFA than acetic acid for enhanced biological phosphorus removal (EBPR), is limited. After the addition of carbohydrate (rice was used as the model matter) to the WAS anaerobic fermentation system to balance the C/N ratio, the effect of pH on WAS protein conversion and VFAs production was investigated in this paper. Experimental results showed that the addition of carbohydrate matter caused a remarkable enhancement of WAS protein conversion and protease activity, and an apparent synergistic effect between WAS and carbohydrate matter was observed. The study of pH effect revealed that pH influenced not only the total VFAs production but the percentage of individual VFA. The maximal VFAs production (52...
381 citations
TL;DR: Methane production was significantly higher and no effect on the characteristics of the digested material was noticed as compared to digesting sewage sludge alone, and at higher grease trap sludge additions, degradation was not complete and methane production either remained the same or decreased.
338 citations
TL;DR: The most significant factor for enhanced FVW digestion performance was the improved organic nitrogen content provided by the additional wastes, and the occurrence of an imbalance between the different groups of anaerobic bacteria which may take place in unstableAnaerobic digestion of FVW could be prevented.
314 citations
TL;DR: This review is to summarize current knowledge on suitability and sustainability of grassland biomass for anaerobic digestion as feedstock for biogas production and economic aspects and environmental impacts are discussed.
293 citations
TL;DR: In this paper, anaerobic digestion of animal byproducts was investigated in batch and semi-continuously fed, reactor experiments at 55°C and for some experiments also at 37°C.
Abstract: Anaerobic digestion of animal by-products was investigated in batch and semi-continuously fed, reactor experiments at 55 °C and for some experiments also at 37 °C. Separate or mixed by-products from pigs were tested. The methane potential measured by batch assays for meat- and bone flour, fat, blood, hair, meat, ribs, raw waste were: 225, 497, 487, 561, 582, 575, 359, 619 dm 3 kg −1 respectively, corresponding to 50–100% of the calculated theoretical methane potential. Dilution of the by-products had a positive effect on the specific methane yield with the highest dilutions giving the best results. High concentrations of long-chain fatty acids and ammonia in the by-products were found to inhibit the biogas process at concentrations higher than 5 g lipids dm −3 and 7 g N dm −3 respectively. Pretreatment (pasteurization: 70 °C, sterilization: 133 °C, and alkali hydrolysis (NaOH) had no effect on achieved methane yields. Mesophilic digestion was more stable than thermophilic digestion, and higher methane yield was noticed at high waste concentrations. The lower yield at thermophilic temperature and high waste concentration was due to ammonia inhibition. Co-digestion of 5% pork by-products mixed with pig manure at 37 °C showed 40% higher methane production compared to digestion of manure alone.
TL;DR: The results showed that the F/I significantly affected the biogas production rate, with lower yields from mesophilic digestion of food waste, green waste and their mixture were lower than the yields obtained at thermophilic temperature.
TL;DR: Up-flow anaerobic sludge blanket (UASB) seems to be a suitable process for the treatment of poultry manure wastewater and the liquid fraction of hen manure, due to its ability to maintain a sufficient amount of active biomass.
TL;DR: Anaerobic digestion is an optimal way to treat organic waste matter, resulting in biogas and residue, and utilization of the residue as a crop fertilizer should enhance crop yield and soil fertility, promoting closure of the global energy and nutrient cycles as mentioned in this paper.
Abstract: Anaerobic digestion is an optimal way to treat organic waste matter, resulting in biogas and residue. Utilization of the residue as a crop fertilizer should enhance crop yield and soil fertility, promoting closure of the global energy and nutrient cycles. Consequently, the requirement for production of inorganic fertilizers will decrease, in turn saving significant amounts of energy, reducing greenhouse gas emissions to the atmosphere, and indirectly leading to global economic benefits. However, application of this residue to agricultural land requires careful monitoring to detect amendments in soil quality at the early stages.
TL;DR: The range of data presented was much larger demonstrating the need to use a consistent and robust approach to GHG accounting and simultaneously accept that some key parameters are highly uncertain, especially of fugitive losses of CH4 and carbon sequestration.
TL;DR: Errors that are commonly made in the quantification of biogas from anaerobic digestion experiments were investigated and an approximately linear variation with flow rate was found; hence in situ calibration is advised for this type of instrument.
TL;DR: The classical problems of lipids methanization in anaerobic processes are discussed and new concepts to enhance lipids degradation are presented and Reactors operation, feeding strategies and prospects of technological developments for wastewater treatment are discussed.
Abstract: The position of high-rate anaerobic technology (HR-AnWT) in the wastewater treatment and bioenergy market can be enhanced if the range of suitable substrates is expanded. Analyzing existing technologies, applications and problems, it is clear that, until now, wastewaters with high lipids content are not effectively treated by HR-AnWT. Nevertheless, waste lipids are ideal potential substrates for biogas production, since theoretically more methane can be produced, when compared with proteins or carbohydrates. In this minireview, the classical problems of lipids methanization in anaerobic processes are discussed and new concepts to enhance lipids degradation are presented. Reactors operation, feeding strategies and prospects of technological developments for wastewater treatment are discussed. Long-chain fatty acids (LCFA) degradation is accomplished by syntrophic communities of anaerobic bacteria and methanogenic archaea. For optimal performance these syntrophic communities need to be clustered in compact aggregates, which is often difficult to achieve with wastewaters that contain fats and lipids. Driving the methane production from lipids/LCFA at industrial scale without risk of overloading and inhibition is still a challenge that has the potential for filling a gap in the existing processes and technologies for biological methane production associated to waste and wastewater treatment.
TL;DR: In this article, the effects of biogas digestion on soil mineral N (SMN) content in spring and autumn were assessed and compared to compare NH3 volatilization following superficial application of different manures to a cereal crop.
TL;DR: The chemical oxygen demand (COD) elimination reached 95.3% demonstrating that cheese whey could be efficiently used for hydrogen and methane production, in a two-stage process.
TL;DR: In this paper, the authors present the current state and discuss benefits of the biogas technology in Nepal and present a systematic and comprehensive study supported by research and development is required to use other degradable waste such as municipal waste to produce Biogas on a large scale.
Abstract: Nepal, one of the least developed countries, is characterized by very low per capita energy consumption. Because of a lack of other commercial sources of energy, the country relies heavily on traditional fuel source, especially firewood. In order to solve the energy problem in rural areas, the country initiated production and distribution of several renewable energy technologies. Among several technologies, biogas has been proved to be viable and emerged as a promising technology. It has been one of the most successful models for the production of clean, environmental friendly, cost effective source of energy and has multiple benefits. In this paper we present the current state and discuss benefits of the biogas technology in Nepal. Improved health, increased crop productivity, saved time for women are some of the major benefits to the users. It provides economic benefit to the country through reduced deforestation and carbon trading. In addition, by reducing green house gas emission, the technology helps in mitigating global warming and climate change. Thus biogas is a renewable, sustainable and clean source of energy that provides multiple benefits; locally and globally. With some exception, cattle dung has been used primarily as an input and the technology is limited to households only. More systematic and comprehensive study supported by research and development is required to use other degradable waste such as municipal waste to produce biogas on a large scale.
01 Jan 2009
TL;DR: In this article, the economic performance of anaerobic digestion of a given biogas plant based on net present value (NPV) and internal rate of return (IRR) concepts is analyzed.
Abstract: Abstract One of the key concerns of biogas plants is the disposal of comparatively large amounts of digestates in an economically and environmentally sustainable manner. This paper analyses the economic performance of anaerobic digestion of a given biogas plant based on net present value (NPV) and internal rate of return (IRR) concepts. A scenario analysis is carried out based on a linear programming model to identify feedstocks that optimize electricity production and to determine the optimal application of digestate. In addition to a default scenario, management and policy scenarios were investigated. Economic evaluations of all scenarios, except no subsidy scenario, show positive NPV. The highest NPV and IRR values are observed under reverse osmosis (RO) as a green fertilizer scenario. Our findings show that treating RO as a green fertilizer, as opposed to manure (default scenario), is not only lucrative for the plant but also lessens environmental burden of long distance transportation of concentrates. This paper also concludes that given the uncertainty of regulations concerning RO and the currently low values of digestate and heat, high investment and operating costs limit feasibility of anaerobic digestion of wastes of farm origin and other co-substrates unless subsidies are provided.
TL;DR: Composting scenario, S3, is the more environmentally preferable alternative to the current waste management system and might be supported with other decision-making tools that consider the economic and social effects of solid waste management.
TL;DR: This research investigated the use of algae for energy generation in a stand‐alone, closed‐loop system that continuously transforms solar energy into energy‐rich biogas and electricity and resulted in a power plant with a potential capacity of about 9 kW of solar algal panel.
Abstract: In the quest for renewable resources, algae are increasingly receiving attention. Their high growth rate, high CO2 fixation and their lack of requirement for fertile soil surface represent several advantages as compared to conventional (energy) crops. Through their ability to store large amounts of oils, they qualify as a source for biodiesel. Algal biomass, however, can also be used as such, namely as a substrate for anaerobic digestion. In the present research, we investigated the use of algae for energy generation in a stand-alone, closed-loop system. The system encompasses an algal growth unit for biomass production, an anaerobic digestion unit to convert the biomass to biogas and a microbial fuel cell to polish the effluent of the digester. Nutrients set free during digestion can accordingly be returned to the algal growth unit for a sustained algal growth. Hence, a system is presented that continuously transforms solar energy into energy-rich biogas and electricity. Algal productivities of 24–30 ton VS ha−1 year−1 were reached, while 0.5 N m3 biogas could be produced kg−1 algal VS. The system described resulted in a power plant with a potential capacity of about 9 kW ha−1 of solar algal panel, with prospects of 23 kW ha−1. Biotechnol. Bioeng. 2009;103: 296–304. © 2009 Wiley Periodicals, Inc.
TL;DR: A review of the production processes and characterization of biogas as an alternative energy source can be found in this article, where the authors discuss the advantages of using the gas generated from organic digestion under anaerobic conditions by mixed population of microorganisms, which has been commenced to be utilized both in rural and industrial areas at least since 1958.
Abstract: This article reviews the production processes and characterization of biogas as an alternative energy source. Biogas, the gas generated from organic digestion under anaerobic conditions by mixed population of microorganisms, is an alternative energy source, which has been commenced to be utilized both in rural and industrial areas at least since 1958. Biogas technology offers a very attractive route to utilize certain categories of biomass for meeting partial energy needs. Unlike other forms of renewable energy, biogas neither has any geographical limitations and required technology for producing energy and it is neither complex or monopolistic.
TL;DR: In this article, the authors carried out an evaluation of the quantities of organic residues coming out from the sugar and alcohol industry (vinasse), urban solid and liquid wastes (garbage and sewage) and livestock residues (bovine and swine manure) in Brazil.
Abstract: The increasing interest in the recuperation of the biogas coming from organic residues, associated with its energetic use is a subject that has been widely discussed Biogas was merely seen as a sub-product obtained from anaerobic decomposition (without oxygen) of organic residue In the paper is carried out an evaluation of the quantities of organic residues coming out from the sugar and alcohol industry (vinasse), urban solid and liquid wastes (garbage and sewage) and livestock residues (bovine and swine manure) in Brazil Finally the electricity generation potential of biogas out of the evaluated sources of organic residues in Brazil is estimated The results of this study indicate that the potential regarding the production of biogas out of the aforementioned organic residues of electricity production using could meet an energy demand of about 105 to 113 % Constraints for biogas energy utilization are identified and discussed
TL;DR: Dilution with active inoculum for increasing the biomass/LCFA ratio, or addition of adsorbents for adsorbing the LCFA and reducing the bioavailable LCFA concentration were found to be the best recovery strategies, improving the recovery time from 10 to 2 days, in semi-continuously fed systems.
TL;DR: In this article, a cane sugar mill was chosen in Cuba and four alternatives were designed for the by-product valorization, and the main characteristics of these alternatives were identified and quantified with the objective of identifying and quantifying the aspects which have the largest environmental impact of using by-products and wastes from the cane sugar process and suggest improvements in the systems.
TL;DR: The effects of crude glycerol on the performance of single-stage anaerobic reactors treating different types of organic waste were examined in this article, where the authors showed that adding 1% v/v COD added to the feed did not have a negative effect on the reactor performance.
TL;DR: It was found that pre-aeration of 48 h generated enough biological heat to increase the temperature of bulk OFMSW to 60 degrees C for the start-up of thermophilic anaerobic digestion without the need for an external heat source.
TL;DR: The best environmental option for the final destination of the sludge is to combine the current situation (fertilizer replacement) with use of theSludge in a cement plant (as a replacement for fuel and raw material).
Abstract: Life cycle assessment (LCA) methodology is used to evaluate the environmental profile of a product or process from its origin to its final destination. In this paper we used LCA to evaluate the current situation of a wastewater treatment plant and identify improvement alternatives. Currently, the highest environmental impacts are caused by the stages of the plant with the highest energy consumption, the use of biogas from anaerobic digestion (95% burned in torch) and the final destination of the sludge (98.6% for agricultural use and 1.4% for compost). We propose four alternatives for biogas applications and five alternatives for sludge applications and compare them to the current situation. The alternatives were incorporated in a decision support system to identify and prioritize the most positive environmental option. Using biogas to produce electricity or a combination of electricity and heat provided the best environmental options since the energy produced would be enough to supply all the stages of t...