Decentralized biogas facilities have become an important component of agricultural sectors in Chinese rural area. This study is the first attempt to investigate how transition in Chinese rural areas ...affects the revolution of decentralized biogas facilities and its sustainability. The characteristics of the household biogas digesters (HBD), simple biogas plants (SBP), and well equipped biogas plants (WEBP) with higher level of technologies were clarified, and their practical feasibility was correspondingly investigated through a comprehensive survey of 15 selected villages. More effort was devoted to the adoption of feedstock availability, energy supply stability, and digestate distribution optimization for each facility. The results showed that feedstock collection and insufficient biogas production were the main restraining factors for HBD, while SBP found to be ineffective facilities for competitive energy production due to the un-guaranteed biogas supply. The survey results demonstrated that the average biogas expenditure of dwellers, who were connected to WEBP, accounted for 39.61% commercial energy cost. According to the one-year operation data collected from a 52-household club revealed that WEBP would effectively maintain stability and continuous biogas supply with the average feeding interval of 6.2 d. Accordingly, WEBP groups were found as the best option for regional development respected with the professional management unit. Overall, commercial biogas is the orientation of decentralized biogas facility construction. However, to form a robust biogas-centric industrial chain, future research should focus on how to establish relative policies and regulations supporting the comprehensive operation framework of a multi-participant collaboration leadership system.
•Decentralized biogas facilities in Chinese rural area have been scrutinized.•Household digesters, simple, and equipped plants are prevalent biogas facilities.•Feedstock collection and low gas production were restraining factors in HBD.•WEBPs were found as the best option for regional development.
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•Analyzed 75 biogas plant accidents (occurrences) globally from 1990 to 2023.•Identified occurrences’ common causes and results and suggested preventive measures.•Correlation screened ...factors related to occurrences, their likelihood, and severity.•Causes are component fail > maintenance > NaTech > equipment > operation > No PPE.•Explosions are the most common accident type, forming 69.3% of all occurrences.
Biogas plants numbers are increasing worldwide, but their safety record is rarely investigated. This paper analyzes 75 occurrences of various types of accidents in biogas plants worldwide between 1990 and 2023. The study comprehensively reviewed accident reports and research literature with input from plant operators and safety experts. We aim to identify the common causes and consequences of accidents (occurrences) and suggest preventive measures to improve safety. The occurrences’ primary causes were component failure > maintenance error > natural and technological disasters (NaTech) > equipment failure > operational error > no personal protective equipment (PPE). The most common occurrences were gas explosions 69.3%, toxic gas releases (biohazard) 21.3%, asphyxia (biohazard) 4%, malfunctioning (electric and mechanical hazard) 2.7%, and fires 2.7%. The accident consequences ranged from minor injuries (76) to fatalities (51) and extensive property damage. Lack of PPE and gas pipelines (mechanical and biohazards) correlated positively and significantly (R2 = 0.70), while operational errors and asphyxia (biohazard) scenarios correlated positively and moderately (R2 = 0.55). The plant design, operating procedures, and maintenance practices strongly influence the occurrences’ likelihood and severity. This study provides valuable insights for stakeholders, researchers, and policymakers interested in promoting biogas’ safe and sustainable development. Future studies should investigate the relationship between plant size and accident frequency and assess the effectiveness of safety management and risk assessment methodologies in mitigating such occurrences.
•Flow fields in biogas plants.•Mixing times in biogas plants.•Characterization of the mixing process in biogas plants.•Reynolds-number for Non-Newtonian fluids.•Non-Newtonian mixing.
The aim of this ...paper was to develop a deeper understanding of the mixing processes in biogas plants and to explore potentials for optimization with respect to efficient mixing. Since slow-running agitators have a higher energy efficiency than high-speed submersible mixers, the focus was placed on paddle agitators. In order to achieve more effective mixing, different agitator positions were compared. The risk of stagnation zones was identified by a current condition analysis with optical velocity measurements. By using different agitator positions stagnation zones can be decreased. In order to evaluate an increase in efficiency, mixing times were determined by conductivity measurements. The results showed that complete mixing can be achieved even at significantly lower speeds if an optimal agitator position is used. With higher viscosity and shear thinning sensitivity of the fluids, the energy-saving potential also increases and the mixing times can be reduced by a factor of 10.
In a developing country such as Pakistan, adopting biogas technology is a complicated process. The government has taken several steps to address energy issues by increasing biogas facilities. This ...research seeks to identify the major barriers to the deployment of biogas plants. Respondents were selected using the snowball sampling method. As a result, 79 adopters of biogas plants participated. Utilizing a structured questionnaire, primary data were collected. Hypotheses were evaluated using partial least squares structural equation modeling (PLS-SEM). Study results demonstrate that all influencing factors are favorably associated with implementing biogas technology, minimizing energy crises, and achieving cost-cutting objectives. In addition, the findings show that properly reducing economic and governmental barriers, encourage farmers to use biogas plants productively and substantially. To build biogas facilities, the government should adopt an economic strategy, owner training, day-to-day operations, and professional technical assistance.
Biogas production is the most important and promising alternative for replacing fossil fuels in an environmentally friendly manner. Along with the many renewable energy sources available, biogas ...production occupies an irreplaceable position due to the undeniable availability of biomass and the need to manage agro-commercial waste. The article reviews the current state of technology used in the production of biogas for selected European examples in terms of methane fermentation efficiency and actual energy production. The novelty of the article is its description of innovative trends that have great potential to play an important role in this field in the near future. The development of the biogas industry in Europe is evident, although the dynamics vary from country to country. Different models are presented, which are based on the different types of feedstock used for biogas production and the proportion of substrates used in co-digesters. Of course, Germany is the undisputed pioneer in the use of this renewable energy source. Nevertheless, the efforts to improve energy self-reliance and environmental impacts are reflected in the growing number of operational biogas plants in other European countries, which provides hope for rapid progress toward the complete abolition of the conventional exploitation of fossil fuels.
Bio-based fertilizers including farmyard manure, sewage sludge, meat and bone meal, composts, digestates and derived products are nutrient-rich fertilizers. They deliver organic matter but may pose ...the risk to contaminate soils by pollutants such as pharmaceuticals, heavy metals, resistance genes or pathogens. Manure and sewage sludge are increasingly used in biogas plants for energy production with the residue being used as fertilizer. It is therefore important to understand the fate of pharmaceuticals during anaerobic digestion. In the present study, 29 biogas plants from three countries were studied. The different input materials and output after digestion were analyzed for selected examples of antibiotics from three different classes, namely tetracyclines (TCs), sulfonamides (SAs) and fluoroquinolones (FQs). These classes are frequently found in animal manures and sewage sludge and display differing mobility and persistence. The results revealed that antibiotics could be detected in 81% of the substrates derived from animal manures and sewage sludge and in 83% of the digestates. Antibiotics were determined with the highest frequency of 100% in sewage sludge where especially ciprofloxacin and tetracycline were found. Highest concentrations were analyzed in poultry dung with in maximum of 8.6 and 8.2 mg/kg DW of enrofloxacin and tetracycline, respectively. After digestion, slightly lower concentrations of antibiotics were determined for most substrates. However, in one biogas plant using poultry dung as an input material a maximum concentration of 15.2 mg/kg DW of tetracycline was determined in the digestate, which after separation accounted for 29.8 mg/kg DW of tetracycline in the liquid phase.
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•A method was optimized for the simultaneous determination of TCs, SAs and FQs.•Antibiotics were determined with the highest frequency of 100% in sewage sludge.•Poultry dung showed highest concentrations with 8.63 and 8.18 mg/kg DW of ENR and TC.•Input and output materials of biogas plants bear the risk to contaminate fields with antibiotics.
The study aimed to assess the most efficient solution of raw material management in selected biogas plants into the concept of circular economy and evaluate the most efficient solution of raw ...material management in selected biogas plants due to the quality and quantity of the feed and the final product obtained, which is biogas, as well at the closed circulation (circular economy). The study evaluated two agricultural biogas plants on a real scale and one at the sewage treatment plant (in real scale) in northeastern Poland. A year-long study showed that in technical terms, the best work efficiency is achieved by agricultural biogas plants processing: silage, manure, apple pomace, potato pulp (biogas plant No. 1), followed by biogas plant No. 3 processing chicken manure, decoction, cattle manure, poultry slaughterhouse waste (sewage sludge, flotate, feathers), and finally, the lowest efficiency biogas plant was No. 2, the sewage treatment plant, which stabilized sewage sludge in the methane fermentation process. Moreover, based on the results, it was found that agricultural biogas gives the best efficiency in energy production from 1 ton of feed.
Biomass is present in ample amounts in rural areas, mainly in agriculture residue and animal wastes. Biogas can be produced from rural solid waste, providing affordable clean energy for rural ...households and a prominent solution to solid waste management. Despite having several benefits of using biogas, the contribution of biogas in rural areas is not as much as expected. Several technical and non-technical barriers are accountable for the slow rate of biogas technology adoption in rural households. Nineteen barriers to household biogas plant adoption in four dimensions of technical, economic, market, and awareness are identified and ranked with the analytical hierarchy process (AHP) in the perspective of rural India. The outcome of the barrier dimension reveals that the economic dimension gets the highest weight of (0.350), followed by the market with a weight of (0.322). At the same time, high installation cost with a weight of (0.141) dominates in the category of barriers, followed by competition from freely available fuel with a weight of 0.105). The gap in capital cost and capital subsidy, lack of paying capacity, and lack of easy credit have positioned respectively third, fourth, and fifth in the overall ranking of barriers with weights of (0.094), (0.084), and (0.08). This paper may contribute significantly to creating greater awareness, evaluating numerous barriers, and adopting biogas technology in India more effectively and efficiently.
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•Identification and ranking of barriers to household biogas plants have been done.•An analytical hierarchy process is utilized for sustainable rural waste management.•Technical, economic, market, and awareness are identified as barriers dimensions.•The most dominant barrier dimension is economic, with a weight of 0.350.•High installation cost is the most decisive barrier, with a weight of 0.141.
•A thermal model is set up for large anaerobic digesters with multimembrane gasholders.•The model is validated using data from one year of operation for a large biogas plant.•Changing from a single- ...to triple-membrane system reduced digester heat input by 52%.•Digestate heat recovery reduced heat input of triple-membrane digester by 68%.•Thermal reinforcement and recovery resulted in a thermally autonomous biogas plant.
Biogas production via anaerobic digestion could approach thermal autarky (less biogas self-consumption and better energy efficiency) using enhanced solutions for thermal insulation based on new multimembrane gasholder configurations, loss avoidance, and heat recovery strategies. In this study, a predictive and configuration-dependent dynamics energy model is developed to daily and seasonally assess the thermal efficiency and heating requirements of industrial biogas plants involving wet digesters with upper multimembrane gasholders. The model is validated using experimental data from a full-scale biogas plant in operation over a one-year period.
The energy model involves a set of dynamic energy balances defined for each compartment of the digester and gasholder. All possible heat sources and sinks (ambient air temperature, wind, rain, and solar radiation) and heat exchanges or losses via advection, convection, and conduction, as well as a complete representation of the infrared radiative networks between the surfaces of the digester, are included for each compartment depending on the operating and design parameters. These heat exchanges are subject to fluctuating environmental conditions (e.g., ambient air temperature, wind, rain, and solar radiation).
The results indicate that triple-membrane gasholders with a third insulation membrane made of a suitable material and thickness, together with the involvement of heat recovery from the digestate advective heat, are capable of reducing the overall thermal losses by more than 95 % (e.g., −51 % of the gasholder cover loss and − 81 % of the advective digestate loss) and when the waste heat from biogas purification is also valorized, the biogas plant can become thermally self-sufficient.
Biomass is a potential energy source for the diversification of the Brazilian energy matrix. In this context, the biogas produced from the anaerobic digestion of residues is a relevant renewable ...resource that plays a significant role in the mitigation of environmental problems and the local generation of electric energy. This review presents the scenario of the biogas production and electricity distributed generation within the Brazilian context. Firstly, it presents an overview of the electric energy generation from biogas and the Brazilian plants that compose this electric matrix. Secondly, the main technologies to produce biogas and the possibilities of its use, followed by the comparison of technologies for distributed generation of electric energy from biogas in the Brazilian market. To illustrate the application of biogas technology, this paper presents a case study of a biogas plant operation and its connectivity to the grid, the Colombari Farm. The information presented here aims to enhance and to foment the recovering of biomass residues to produce biogas via anaerobic digestion and its utilization to generate electricity. Although the case study considers a specific plant in Brazil, the information and results presented can be applied to others areas of the country or regions of the world, so contributing to promote the expansion of biogas plants to generate electricity. Finally, a future perspectives section describes the practical implications of the biogas production and electricity generation in rural and urban areas and its contribution to the implementation of Brazilian environmental and social policies. This review also is useful to support the research development of biogas for electricity production.
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•Biogas applied Distributed Generation in the Brazilian Market.•Different types of biodigesters and its biogas production.•Technologies for biogas production and electric power generation.•Study of the first biogas generation plant: Colombari Farm at Parana, Brazil.
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