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Annually, a huge amount of waste from plant biomass and animal manure is produced from agriculture and animal farming. Many studies provide information on the biomethane potential of agricultural and livestock wastes, but only a few studies have investigated the application of the substrates in combination. The objective of the study is to enhance the fermentation process in the digester for biogas production, obtained from animal and plant waste substrates. In four batch processes for three months, the temperatures and the residence time of the substrates in the fermenter were analyzed. Simultaneously, electricity and thermal energy were produced via cogeneration units, which were exported to the public grid and city heating network. The plant substrate is a silage mixture of corn and wheat waste. The animal substrate is a mixture of beef and pig manure. Animal and vegetable waste raw materials are collected and transported to the site, located in the region of southeastern Bulgaria. The total annual consumption of animal and plant waste is 17,971 t/year. The enhancement of the process leads to the production of 1,506,000 Nm3 CH4/a of methane, the generation of which requires 299.63 MWh/a of electricity and 649.09 MWh/a thermal energy. [ABSTRACT FROM AUTHOR]

Biodegradable waste from households, companies, and gastronomy is not utilized in large Polish agglomerations for the production of biogas. Determining the biogas production potential in a selected agglomeration will enable the implementation of circular economy goals and sustainable development objectives. Once appropriate odor neutrality standards are met, biogas plants could be constructed around large cities, supplying both energy and heating systems to nearby housing estates or production facilities. This article aims to assess the potential of biodegradable municipal waste collected in a large city for the production of energy in specialized municipal biogas plants. The following analytical study focuses on Krakow and its surrounding municipalities. Because of its geographical location, Krakow is exposed to smog, and every action limiting the usage of carbon-based materials for heating will have a positive impact on the air quality. A biogas plant powered by municipal waste would present a viable opportunity to limit urban smog. It is also crucial that a biogas plant can store energy as it is equipped with methane tanks. Both renewable and other energy sources are still awaiting functional technical solutions that would allow for optimal energy storage. [ABSTRACT FROM AUTHOR]

Poland has a large potential for biogas production from agricultural sources and food waste. This potential is still poorly used. There are many reasons for this state of affairs. We can indicate both the policy of the state towards renewable energy sources (RES) with a small amount of energy from biogas contracted at auctions, investment risk, and especially low return on investment in the absence of investment support. An important reason is also the limited state budget. The purpose of this work was to determine the endogenous factors that determine ROE, the direction of the impact of these factors, as well as the strategy of biogas plants in shaping the ROE level. The DuPont model was used in the analysis of ROE changes. We used the deviation method to determine the impact of the various factors on ROE. Against the background of the energy sector in Poland, the value of ROE in the examined biogas plants should be considered satisfactory, and in 2020 it was, on average, 13.9%. The decrease from 17.2% in 2019 occurred despite the increase in energy prices and the increase in the net profit margin (NPM). It resulted from the reduction of ROE's financial leverage through external capital. A high level of debt characterized the examined biogas plants, and the pursuit of risk reduction and debt reduction negatively impacts on ROE. This may indicate the need for state investment support at the plant construction stage or low-interest investment loans to develop biogas plants. In addition, using only price guarantees under the feed-in tariffs, with dynamic changes in costs, may bring the industry a relatively high investment risk compared to other RES, where the operational costs during the lifetime are low, as it is in PV or wind systems. [ABSTRACT FROM AUTHOR]

The economic management of lignocellulosic biomass from semi-natural grasslands is now a challenge across Europe. The abandonment of mowing these grasslands leads to the gradual degradation of these ecosystems. This study investigates how chemical and biological factors affect the suitability of biomass from abandoned grasslands for biogas production. We sampled 30 mown and 30 abandoned grassland sites in the Sudetes Mountains (Poland and Czechia). The cover contribution of short herbs was found to be significantly higher in mown grasslands (p < 0.001), while that of tall herbs was more prevalent in abandoned grasslands (p < 0.01). The specific biogas yield (SBY, NL kg−1 volatile solids) is negatively affected by an increased percentage of herbs in the biomass of mown and abandoned grasslands. This is due to the inhibitory effect of herbs on biodegradation, the increase in lignin content and the decrease in cellulose. This study highlights the importance of individual plant species in assessing grassland biomass for area biogas yield (ABY, m3 ha−1) and provides new insights into a field that has not yet been extensively investigated. In mown grasslands, ABY was most positively correlated with grass species (Arrhenatherum elatius , Trisetum flavescens and Festuca pratensis). In abandoned grasslands, the ABY was most correlated with herbaceous species (Galium aparine , Urtica dioica and Chaerophyllum aromaticum) and grasses (A. elatius and Elymus repens). Mown grasslands had significantly higher species richness (p < 0.001) compared to abandoned grasslands, but the number of species sampled did not correlate with SBY and ABY. This study contributes to the development of a sustainable bio-economy by highlighting the need for efficient use of grassland biomass. This approach helps protect semi-natural ecosystems and facilitates sustainable management of renewable resources. • Certain grassland plant species significantly impact area biogas yield. • Species richness has no negative effect on specific and area biogas yield. • Grassland management maintains an appropriate ratio of herbs to grasses. • Biogas production from hay can help restore abandoned grassland. [ABSTRACT FROM AUTHOR]

A 1200‐m3 full‐scale biogas plant treating highly polluted wastewater (WW) from the cleaning of tank cars transporting food and fodder is working stably and efficiently despite the WW is constantly varying in strength and composition, is easily acidifying, and low in alkalinity. Na2CO3 has to be added to maintain the digester alkalinity and the digester pH at defined values due to softened water used for car tank cleaning. Monitoring volatile organic acid concentration and controlling the alkalinity in the digester are essential for maintaining the digestion process stability. Biogas production is adapted to the demand by a modulated feeding regime. The drastic modulation of feeding is possible due to the moderate organic loading of the plant along with the high average hydraulic retention time. [ABSTRACT FROM AUTHOR]

Abstract 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. Graphical abstract fx1 Highlights • 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. [ABSTRACT FROM AUTHOR]

Up to the latest versions of the German renewable energy act (EEG), there had been a constant growth of new biogas plants (BGPs). After reaching a stagnation in the last years, today the focus has shifted to improving the existing BGPs. Assuming that most plants have not reached the technical end of life, the question arises on how an operation can be realized beyond the initial EEG support period of 20 years. In addition, new legal and economic conditions require the implementation of adjustments, that is, "repowering measures." Based on a method review, a plant‐specific model approach is presented to assess repowering measures for a wide range of BGPs differing in capacity, substrate mixture and agricultural structures. The techno‐economic model includes different performance indicators like levelized cost of electricity (LCOE) and temporal aspects like technical progress. Using a data set for BGPs in the state of Baden‐Wuerttemberg (Germany), results are illustrated for the different model modules and three repowering scenarios of an extended operation period of ten years. The scenarios regard different options to meet the requirements of the current EEG, namely the flexibilization and restrictions on energy crops, in comparison with a reference case. While in repowering scenarios, the number of plants decreases between 54% and 69% and the overall power capacity changes between −48% and 13% until 2035. The results further show a reduction potential in the specific area demand and GHG emission up to 12% and 24%, respectively. Technical progress, additional revenues and capacity premiums are shown to be an important factor for efficient substrate utilization, low LCOE and thereby the enabling of an extended operation period. The scenario results indicate that the agricultural areas for energy crop cultivation and the amount of manure used in BGPs will be reduced considerably, inducing new chances and challenges in the future. Due to constantly changing framework conditions, existing biogas plants in Germany are required to conduct repowering measures to continue the operation. Using a plant‐specific model approach, the impact of these repowering measures has been assessed for a wide range of plants in the state of Baden‐Württemberg. Different scenarios show that repowering can improve efficiency and reduce specific GHG emissions. Yet, under current framework conditions, the number of biogas plants is strongly decreasing. Changes in the public support system are needed if more plants should be enabled to continue their operation. [ABSTRACT FROM AUTHOR]

With today's growing focus on on-demand energy production, the dynamic operation of biogas plants is becoming more and more important. Detecting unacceptable load changes and so preventing process failures is vital. In the present contribution, we propose an operating scheme that includes the detection of disturbances and intervention. This is then evaluated systematically with the help of a mathematical model for step changes in the organic loading rate. We summarize the qualitative results for each diagnosis variable in an operation diagram, enabling an intuitive, comprehensive comparison. Of the diagnosis variables analyzed, we find that the most promising for identifying incipient process failures in biogas plants are the volatile fatty acids to total alkalinity ratio (VFA/TA), followed by the ratio of methane to carbon dioxide γ in the biogas. In addition, the combination of the online measured variables pH value and gas composition can reveal disturbances early on in a wide range of different conditions. [ABSTRACT FROM AUTHOR]

The study presents the development of a method for the long term monitoring of methane emissions from pressure relief valves (PRV 1 PRV: pressure relief valve. 1 ) of biogas storages, which has been verified during test series at two PRVs of two agricultural biogas plants located in Germany. The determined methane emission factors are 0.12 g CH 4 kWh el −1 (0.06% CH 4 -loss, within 106 days, 161 triggering events, winter season) from biogas plant A and 6.80/7.44 g CH 4 kWh el −1 (3.60/3.88% CH 4 -loss, within 66 days, 452 triggering events, summer season) from biogas plant B. Besides the operational state of the biogas plant (e.g. malfunction of the combined heat and power unit), the mode of operation of the biogas flare, which can be manually or automatically operated as well as the atmospheric conditions (e.g. drop of the atmospheric pressure) can also affect the biogas emission from PRVs. [ABSTRACT FROM AUTHOR]

A biogas production plant operating with main and secondary digesters (MD, SD) was analysed for the diversity of bacteria from Clostridium cluster I and its pathogenic members. The plant was run in two parallel lines, both receiving silages, and one, in addition, cattle manure (CM). Quantitative PCR of 16S rRNA genes from directly extracted DNA indicated that cluster I represented 0.2 to 5.6 % of the total bacterial communities. Its prevalence was particularly low in CM and also in SD compared to MD, indicating its decline during fermentation. In contrast, another highly abundant clostridial group, i.e. the 'faecal' cluster XIVa, remained quantitatively unaffected during fermentation. A total of 85.1 % of 581,934 rRNA gene sequences gathered by group-specific PCR from the silages, CM and digesters could be assigned to cluster I. All remaining sequences fell into other clostridial groups. The three most dominant operational taxonomic units (OTUs) introduced with CM were from cluster I, and they declined during fermentation. Fermentation with CM significantly increased OTUs of clostridia outside of cluster I but not within. The only OTUs related to pathogens were detected for Clostridium botulinum with 0.18 % of all cluster I sequences in maize silage and less than 0.01 % in the other substrates and digester materials. These OTUs could be assigned to all four established C. botulinum groups, thus, potentially covering all seven neurotoxins. Mouse lethality tests of samples with suspected presence of C. botulinum, however, indicated no toxigenic potential and, thus, no risk associated with the rare occurrence of these OTUs. [ABSTRACT FROM AUTHOR]

Purpose: The two main reasons for producing biomethane as renewable fuel are reduction of climate impacts and depletion of fossil resources. Biomethane is expected to be sustainable, but how sustainable is it actually? This article contributes to the clarification. Therefore, the environmental impacts of several biomethane facilities all over Europe were assessed. A special focus is put on the differences between the facilities as they follow different production routes. Methods: The method used for evaluation is life cycle assessment (LCA) applied in a well-to-wheel approach. This enables to show the overall performance in terms of global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), photochemical ozone creation potential (POCP) and PE fossil. The system boundary includes the entire chain from biogas production to upgrading, distribution and use. For evaluating the different production routes several years of measuring data, calculating and improving the LCA models in close cooperation with the plant operators were carried out. Results and discussion: The evaluation of the production routes shows a high reduction potential compared to fossil fuels. Regarding the depletion of fossil resources, the amounts vary between the sites, but the reduction is at least 50 % and reaches almost 100 % reductions at some sites. The reduction of GWP is at least 65 %, because waste flows free of environmental burdens are used almost exclusively as substrate. Other dominant factors are power and heat demand, methane losses to the environment and the use of by-products, e.g. fertilizer. Conclusions: Despite this caveat, the evaluated systems demonstrate the possible positive results of renewable fuel production if done properly. [ABSTRACT FROM AUTHOR]

Abstract: The major attempt of this paper is to examine the factors affecting the biogas technology adoption in rural areas in Bangladesh. The study was conducted by a survey method on respondents. Stratified random and purposive sampling techniques were applied for selecting 150 biogas users and 150 non-users. Data were collected through individual interviews by using structural questionnaire. A qualitative response model (Logistic regression model) was applied for examining the main factors influencing the biogas adoption. As a result, socio-economic factors play an important role in the respondents' behaviors toward biogas adoption. The empirical results indeed highlighted that year of education, income level, number of cattle, and women headed family have significant influences on the decision of biogas plant installation. Subsequently, increasing the level of education, empowering women, enhancing the yearly income and number of cattle are strategies likely to increase the adoption rate of biogas plants. Environmental, economic, social, and technological benefits were considered by the respondents while engaging in the biogas plant adoption. Households are also motivated toward biogas plant installation by Non Governmental Organizations (NGOs). A tiny motivation comes from Governmental Organizations (GOs), local government, electronic and print media. Therefore, raising the population awareness on the benefits of biogas plant installation through the existing channels of communication campaigns, provision of financial incentive, participation of print media and active attendances of Government institutions could extend the biogas technology in Bangladesh. [Copyright &y& Elsevier]

A growing population, technological progress and economic development result in a constant increase in energy demand. Energy is mostly obtained from fossil energy resources such as coal, natural gas, and crude oil. Burning them leads to air pollution with greenhouse gases (CO2, CH4, NH3 and N2O) and dust (PM2.5 and PM10). They are recognized as the cause of global warming and air pollution. Wind, water, solar and biomass energy are used to eliminate harmful emissions. The latter may come from special plant crops or from biodegradable waste from farming, animal husbandry, the agrifood industry and households. These wastes are transformed into biogas in biogas plants, the basic ingredient of which is methane. Most often, biogas is burned in a cogeneration process, providing electricity and heat. After purification of admixtures, it can be injected into the high-methane gas network or converted into hydrogen in the steam reforming process. In this way, environmentally harmful waste becomes a raw material for energy production, which is an example of a circular economy. The article discusses the functioning of biogas plants in selected EU countries. The current biogas production in Poland was assessed and compared with the production potential of dairy farms. The aim of this article was to show that the production of biogas reduces the emission of greenhouse gases into the atmosphere and the electricity produced from it is not burdened with the cost of purchasing CO2 emission allowances applicable in the EU. [ABSTRACT FROM AUTHOR]

This article deals with the analysis of instrumentation from three modern German full-scale biogas plants with different inputs and typical process engineering concepts for German conditions. The measured results from each plant and the suitability of the instrumentation used are evaluated and assessed. Conclusions are also made about improving the use and architecture of the instrumentation. The analysis results show which benefits and optimum combination of on-line and off-line instrumentation could result for the control and automation of industrial and agricultural biogas plants. [ABSTRACT FROM AUTHOR]

This paper give information about German biogas plant at middle and big scale. That research was executed with support of Rostock University and Hohenheim University. The main objective is to show the properties of German biogas plant at middle and big scale and it's possible use in undevelopment country like as Cuba. [ABSTRACT FROM AUTHOR]

A study on 18 full-scale centralized biogas plants was carried out in order to find significant operational factors influencing productivity and stability of the plants. It was found that the most plants were operating relatively stable with volatile fatty acids (VFA) concentration below 1.5 g/l. VFA concentration increase was observed in occasions with dramatic overloading or other disturbances such as operational temperature changes. Ammonia was found to be a significant factor for stability. A correlation between increased residual biogas production and high ammonia was found. When ammonia was higher than approx. 4 g-N/l the degradation efficiency of the plant decreased and as a consequence, the residual methane potential was high. Decrease of the residual methane potential with increasing hydraulic retention time was found. Digestion temperature was very important for effective post-digestion. Post-digestion for recovering the residual methane potential at temperatures below 15 °C was very inefficient. [ABSTRACT FROM AUTHOR]

The biogas production technology has improved over the last years for the aim of reducing the costs of the process, increasing the biogas yields, and minimizing the greenhouse gas emissions. To obtain a stable and efficient biogas production, there are several design considerations and operational parameters to be taken into account. Besides, adapting the process to unanticipated conditions can be achieved by adequate monitoring of various operational parameters. This paper reviews the research that has been conducted over the last years. This review paper summarizes the developments in biogas design and operation, while highlighting the main factors that affect the efficiency of the anaerobic digestion process. The study's outcomes revealed that the optimum operational values of the main parameters may vary from one biogas plant to another. Additionally, the negative conditions that should be avoided while operating a biogas plant were identified. [ABSTRACT FROM AUTHOR]