Showing papers on "Biogas published in 2010"
TL;DR: The current state and perspectives of biogas production, including the biochemical parameters and feedstocks which influence the efficiency and reliability of the microbial conversion and gas yield are reviewed.
Abstract: Anaerobic digestion of energy crops, residues, and wastes is of increasing interest in order to reduce the greenhouse gas emissions and to facilitate a sustainable development of energy supply. Production of biogas provides a versatile carrier of renewable energy, as methane can be used for replacement of fossil fuels in both heat and power generation and as a vehicle fuel. For biogas production, various process types are applied which can be classified in wet and dry fermentation systems. Most often applied are wet digester systems using vertical stirred tank digester with different stirrer types dependent on the origin of the feedstock. Biogas is mainly utilized in engine-based combined heat and power plants, whereas microgas turbines and fuel cells are expensive alternatives which need further development work for reducing the costs and increasing their reliability. Gas upgrading and utilization as renewable vehicle fuel or injection into the natural gas grid is of increasing interest because the gas can be used in a more efficient way. The digestate from anaerobic fermentation is a valuable fertilizer due to the increased availability of nitrogen and the better short-term fertilization effect. Anaerobic treatment minimizes the survival of pathogens which is important for using the digested residue as fertilizer. This paper reviews the current state and perspectives of biogas production, including the biochemical parameters and feedstocks which influence the efficiency and reliability of the microbial conversion and gas yield.
2,440 citations
TL;DR: This paper presents a review of the main sludge treatment techniques used as a pretreatment to anaerobic digestion, and it is likely that low impact pretreatment methods such as mechanical and thermal phased improve speed of degradation, while high impact methods improve both speed and extent of degradation.
1,058 citations
TL;DR: In this paper, the authors evaluated the energy efficiency of different biogas systems, including single and co-digestion of multiple feedstock, different biogenetic pathways, and waste-stream management strategies.
688 citations
TL;DR: It is concluded that selected algae species can be good substrates for biogas production and that anaerobic fermentation can seriously be considered as final step in future microalgae-based biorefinery concepts.
651 citations
TL;DR: Adding the food waste into a manure digester at levels up to 60% of the initial volatile solids significantly increased the methane yield for 20days of digestion, showing that a hydraulic retention time of 20days could be recommended for a continuous digester.
580 citations
TL;DR: The results showed that digestates differed from ingestates and also from compost, although the starting organic mix influenced the digestate final characteristics, and appears to be a very good candidate to replace inorganic fertilizers, also contributing, to the short-term soil organic matter turnover.
414 citations
TL;DR: In this paper, the effects of particle size reduction and solubilization on biogas production from food waste (FW) were investigated in detail, where substrates of various particle sizes were prepared by bead milling to support hydrolysis.
386 citations
TL;DR: It was seen that organic and inorganic compounds are efficiently solubilised during thermal treatment and a higher temperature and a longer treatment time are beneficial for the release.
361 citations
TL;DR: Simultaneous NaOH treatment and anaerobic digestion did not significantly improve the biogas production (P>0.05), and a higher NaOH loading caused faster production of volatile fatty acids during the hydrolysis and acidogenesis stages, which inhibited the methanogenesis.
348 citations
TL;DR: It is proposed herewith that wastewater management based on the promotion of cleaner production and environmentally sound biotechnologies should be prioritized and included as a part of the POME management in Malaysia for attaining sustainable development.
339 citations
TL;DR: In this article, the development process and present status of household biogas, specifically the opportunities and constraints of household Biogas in rural China, are discussed in this paper.
Abstract: As a renewable energy, biogas is not only an important part of the development of rural new energy, but also an important aspect of sustainable development in China. The development process and present status of household biogas, specifically the opportunities and constraints of household biogas in rural China, are discussed in this paper. Only about 19% of the biogas potential has been utilized in rural China. There are several opportunities for household biogas development in rural China, including the problem of rural household energy consumption, the availability of biogas fermentation materials, national financial subsidies, legal and international clean development mechanisms. Also, more research needs to be done in straw fermentation and cold fermentation technology. Training should be conducted to raise the level of biogas customers in comprehensive biogas utilization. Measures should be taken to improve the follow-up services and management of biogas plants. The information presented in this paper will be helpful not only to the sustainable development of household biogas in rural China, but also to the development of biogas in similar countries around the world.
TL;DR: In this article, a method for biogas scrubbing and CH 4 enrichment is presented, where a packed column of liquid solvents are circulated through the column, contacting the Biogas in countercurrent flow, and test results revealed that the aqueous solutions used were effective in reacting with CO 2 in BiOGas, creating CH 4 enriched fuel.
TL;DR: The potential of biogas generation from anaerobic digestion of different waste biomass in India has been studied in this article, where the authors have shown that renewable energy from biomass is one of the most efficient and effective options among the various other alternative sources of energy currently available.
Abstract: The potential of biogas generation from anaerobic digestion of different waste biomass in India has been studied. Renewable energy from biomass is one of the most efficient and effective options among the various other alternative sources of energy currently available. The anaerobic digestion of biomass requires less capital investment and per unit production cost as compared to other renewable energy sources such as hydro, solar and wind. Further, renewable energy from biomass is available as a domestic resource in the rural areas, which is not subject to world price fluctuations or the supply uncertainties as of imported and conventional fuels. In India, energy demand from various sectors is increased substantially and the energy supply is not in pace with the demand which resulted in a deficit of 11,436 MW which is equivalent to 12.6% of peak demand in 2006. The total installed capacity of bioenergy generation till 2007 from solid biomass and waste to energy is about 1227 MW against a potential of 25,700 MW. The bioenergy potential from municipal solid waste, crop residue and agricultural waste, wastewater sludge, animal manure, industrial waste which includes distilleries, dairy plants, pulp and paper, poultry, slaughter houses, sugar industries is estimated. The total potential of biogas from all the above sources excluding wastewater has been estimated to be 40,734 Mm 3 /year.
TL;DR: Alternative methods for determining the anaerobic biodegradability of solid waste are presented and spectroscopy techniques seem to be useful for determining biodegradation, in particular by taking into account the interaction between different molecules in the organic matter.
TL;DR: A combination of acetate, propionate and biogas production is an effective combination to monitor this type of digesters effectively, and pH was relatively stable and did not show clear response to hydraulic load changes.
TL;DR: In this article, the effect of thermal and sonication pre-treatment on the degradation of sewage sludge was evaluated through the calculation of performance parameters by using three simplified mathematical models and one kinetic model.
TL;DR: It was showed that a microbial fuel cell does not provide a significant environmental benefit relative to the "conventional" anaerobic treatment option, but a microbial electrolysis cell provides significant environmental benefits through the displacement of chemical production by conventional means.
Abstract: Existing wastewater treatment options are generally perceived as energy intensive and environmentally unfriendly. Much attention has been focused on two new approaches in the past years, (i) microbial fuel cells and (ii) microbial electrolysis cells, which directly generate electrical current or chemical products, respectively, during wastewater treatment. These systems are commonly denominated as bioelectrochemical systems, and a multitude of claims have been made in the past regarding the environmental impact of these treatment options. However, an in-depth study backing these claims has not been performed. Here, we have conducted a life cycle assessment (LCA) to compare the environmental impact of three industrial wastewater treatment options, (i) anaerobic treatment with biogas generation, (ii) a microbial fuel cell treatment, with direct electricity generation, and (iii) a microbial electrolysis cell, with hydrogen peroxide production. Our analysis showed that a microbial fuel cell does not provide a significant environmental benefit relative to the "conventional" anaerobic treatment option. However, a microbial electrolysis cell provides significant environmental benefits through the displacement of chemical production by conventional means. Provided that the target conversion level of 1000 A.m(-3) can be met, the decrease in greenhouse gas emissions and other environmentally harmful emissions (e.g., aromatic hydrocarbons) of the microbial electrolysis cell will be a key driver for the development of an industrial standard for this technology. Evidently, this assessment is highly dependent on the underlying assumptions, such as the used reactor materials and target performance. This provides a challenge and an opportunity for researchers in the field to select and develop appropriate and environmentally benign materials of construction, as well as demonstrate the required 1000 A.m(-3) performance at pilot and full scale.
TL;DR: Water consumption in a fish-processing industry and high-strength wastewater from such an industry are of great concern and liquid effluent regulations are becoming more stringent day by day.
TL;DR: According to trial results and considering the availability of examined biomasses in Italy, it is possible to estimate their total energetic potential close to a value of 21,900TJ *year(-1).
TL;DR: In this article, a 3x3 experimental design with duplicates was adopted (3 crop residuesx3 carbon/nitrogen ratios) to examine the improvement of batch digestion in terms of biogas volume produced.
TL;DR: The main principles of commercial siloxane removal systems are introduced, scientific progress in the field over the last decade is reviewed and new concepts based on technologies other than sorption or condensation are reviewed.
TL;DR: In this article, an investment decision kit for economic evaluation of biogas plant projects based on agricultural feedstocks is presented, which can be used to compare different conditions adapted to local situations to treat the targeted residues.
Abstract: Anaerobic digestion is a very promising solution for the treatment of agricultural waste, preventing pollution and leading to efficient energy production. Since this technology is available to each farmer in a different way depending on the location and the scattering of the primary sources, it is essential to clarify the best conditions adapted to local situations to treat the targeted residues and make this information accessible to farmers. In particular the possibility of codigestion seems to be very attractive for farmers who will be able to treat their own waste together with other organic substrates. Their profit in this case is double since they treat properly their own residues, taking advantage of the selling of heat and electricity as well as the utilisation of a stabilised biofertiliser. The aim of this paper is to present an investment decision kit for economic evaluation of biogas plant projects based on agricultural feedstocks.
TL;DR: In this article, the authors proposed basic concepts for the integration of membrane biogas upgrading plants into the existing plants while taking into account the permeate utilisation and the heating requirements of the plants.
TL;DR: In this article, anaerobic digestion of lignocellulosic crops on marginal and set-aside lands is a more environmentally sound and sustainable option for renewable energy production, since the whole substrate excepted lignin is convertible into methane.
Abstract: The methane produced from the anaerobic digestion of organic wastes and energy crops represents an elegant and economical means of generating renewable biofuel. Anaerobic digestion is a mature technology and is already used for the conversion of the organic fraction of municipal solid wastes and excess primary and secondary sludge from waste-water treatment plants. High methane yield up to 0.45 m3 STP CH4/kg volatile solids (VS) or 12 390 m3 STP CH4/ ha can be achieved with sugar and starch crops, although these cultures are competing with food and feed crops for high-quality land. The cultivation of lignocellulosic crops on marginal and set-aside lands is a more environmentally sound and sustainable option for renewable energy production. The methane yield obtained from these crops is lower, 0.17–0.39 m3 STP CH4/kg VS or 5400 m3 STP CH4/ha, as its conversion into methane is facing the same initial barrier as for the production of ethanol, for example, hydrolysis of the crops. Intensive research and development on efficient pre-treatments is ongoing to optimize the net energy production, which is potentially greater than for liquid biofuels, since the whole substrate excepted lignin is convertible into methane. Copyright © 2010 Crown in the right of Canada
TL;DR: In this article, the authors used biogas in a HCCI engine with charge temperature and amount of diesel injected into the intake manifold being used to control combustion, and the best energy ratio was 50%.
TL;DR: It can be concluded that glycerol uptake is not the rate-limiting step during the process, and biogas yields can be boosted if it does not exceed a limiting 1% concentration in the feed.
TL;DR: The paper deals with the benefits coming from the application of a proper process temperature (55 degrees C) instead of a 'reduced' thermophilic range (47 degrees C), that is often applied in European anaerobic co-digestion plants.
TL;DR: This work suggests a new platform using volatile fatty acids (VFAs) for the production of biofuels and biochemicals production, which does not need sterilization, additional hydrolysis enzymes (cellulose or xylanase), or a high cost pretreatment step.
Abstract: The typical biorefinery platforms are sugar, thermochemical (syngas), carbon-rich chains, and biogas platforms, each offering unique advantages and disadvantages. The sugar platform uses hexose and pentose sugars extracted or converted from plant body mass. The thermochemical (syngas) platform entails a chemical or biological conversion process using pyrolysis or gasification of plants to produce biofuels. The carbon-rich chains platform is used to produce biodiesel from long-chain fatty acids or glycerides. In the present work, we suggest a new platform using volatile fatty acids (VFAs) for the production of biofuels and biochemicals production. The VFAs are short-chain fatty acids composed mainly of acetate and butyrate in the anaerobic digestion (AD) process, which does not need sterilization, additional hydrolysis enzymes (cellulose or xylanase), or a high cost pretreatment step. VFAs are easily produced from almost all kinds of biomass with low lignin content (terrestrial, aquatic, and marine biomass) by the AD process. Considering that raw material alone constitutes 40∼80% of biofuel production costs, biofuels made from VFAs derived from waste organic biomass potentially offer significant economical advantage.
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: 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: It was found that pretreating sludge at pH 10 caused the greatest sludge hydrolysis, acidification, soluble C:N and C:P ratios, and Fe(3+) concentration with a suitable short-chain fatty acids composition in the first stage, which resulted in the highest microorganism activity (ATP) and methane production in the second phase.
Abstract: During two-phase sludge anaerobic digestion, sludge is usually hydrolyzed and acidified in the first phase, then methane is produced in the second stage. To get more methane from sludge, most studies in literature focused on the increase of sludge hydrolysis. In this paper a different sludge pretreatment method, i.e., pretreating sludge at pH 10 for 8 d is reported, by which both waste activated sludge hydrolysis and acidification were increased, and the methane production was significantly improved. First, the effect of different sludge pretreatment methods on methane yield was compared. The pH 10 pretreated sludge showed the highest accumulative methane yield (398 mL per g of volatile suspended solids), which was 4.4-, 3.5-, 3.1-, and 2.3-fold of the blank (unpretreated), ultrasonic, thermal, and thermal-alkaline pretreated sludge, respectively. Nevertheless, its total time involved in the first (hydrolysis and acidification) and second (methanogenesis) stages was 17 (8 + 9) d, which was almost the same...