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Due to the decarbonization of the energy system, natural gas will only play a minor role as an energy source after 2045. To decarbonize the gas supply in the future, there are two options for green gases: hydrogen or biomethane. The injection of green gases into the existing gas infrastructure leads to changes in the gas composition, requiring a consideration of the framework conditions for distribution. Adjustments to the grid for transport may be required. Consequently, this paper presents the main characteristics of hydrogen and biomethane and examines the suitability of the gas infrastructure for their transportation. A case study for the development of gas infrastructure in Germany is presented. The focus is on the further development of biogas, concentrating on the question of which biogas should optimally be upgraded in the future to enable its be distribution in the long term. [Display omitted] • Dedication of gas infrastructure to hydrogen in competition with the distribution of biomethane. • Examination of the suitability of the infrastructure for the distribution of green gases. • Gas grid development pathways in Germany. • Role of biogas in future gas supply. [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]

A biogas plant is fed with agricultural substrates at an average organic loading rate of 6 kgVS per m3 fermenter volume per day and substrates with relatively high nitrogen content. This situation results in a below‐average methane yield, so the aim is to increase the substrate efficiency. An analysis of the actual condition of the plant was performed and compared with reference values. A dynamic simulation model of the biogas plant was created and adjusted with data over an operating year. The model adjustment provided a good approximation of the simulation results to the key operating variables and thus allows the evaluation of different operating variations. The effect of various measures was analyzed by simulation and it showed a potential increase in substrate efficiency of up to 15 %. [ABSTRACT FROM AUTHOR]

Simple Summary: The extensive use of animal wastes as fertilizers, often in an uncontrolled manner, may cause the spread of zoonotic diseases as they provide a nutrient-rich environment for pathogens. This study aims to determine the impact of the methane fermentation process carried out in two agricultural biogas plants, which differed in the type of substrates used (pig slurry from a maternal farm versus pig slurry from a fattening farm), on the efficiency of sanitization of biomass. The obtained results lead to the conclusion that the effectiveness of biomass sanitization is significantly higher when pig slurry from a fattening farm is used as a substrate, which offers a clear recommendation for the location of biogas plants in their vicinity. Large-scale pig farming is associated with the production of large amounts of animal excrement, which, after processing into the form of, e.g., slurry, are managed on agricultural land as natural fertilizers. The utilization of pig manure on agricultural land in an excessive and uncontrolled manner may pose a threat to zoonoses due to the significant amounts of potentially pathogenic microorganisms within its content. This study aims to determine the impact of the methane fermentation process carried out in two agricultural biogas plants on the efficiency of sanitization of pig slurry, input biomass, and digestate. The biogas plants differed in terms of the substrate used; one used pig slurry from a maternal (breeding) farm (BP-M), and the other utilized pig slurry from a fattening farm (BP-F). The physicochemical analyses showed that the slurry, input biomass, and digestate from the BP-F were characterized by a significantly higher contents of organic dry matter, ash, and ammonium nitrogen than the slurry, input biomass, and digestate from the BP-M. The parameters of the methane fermentation process, including temperature and pH, reached higher values in the BP-F compared to the BP-M. The microbiological analyses led to the conclusion that the efficiency of sanitization of input biomass, including pig slurry, was significantly higher in the BP-F compared to the BP-M. Due to the above findings, locating biogas plants near pig fattening farms should be recommended. [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]

[Display omitted] • 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. [ABSTRACT FROM AUTHOR]

The present study evaluated the potential of a self‐resilient rural bio‐energy model using a case study from a village in Uttar Pradesh, India. A total biogas potential of 400 329 m3/year was estimated from area using agricultural residues and livestock wastes, thus capable of establishing biogas plants in a centralized (20 to 100 m3) or decentralized (2 to 20 m3) manner. For the three scenarios were considered in this study, i.e., (I) combined electricity and thermal energy generation, (II) for direct cooking, and (III) according to energy requirements, a maximum electricity generation and thermal energy potential were estimated to up to 800 658 and 1 200 988 kWh. A maximum amount of 162 646 kg.year–1 of firewood, 443 190 kg.year–1 of dung cake, 70 996 kg.year–1 of charcoal and 13 713 kg of liquified petroleum gas could be replaced using produced raw biogas, which is even higher if the biogas is upgraded. In the third scenario, a maximum surplus amount of 169 894 m3.year–1 of raw biogas and 221 969 m3.year–1 of upgraded biogas are available if all the available wastes are co‐digested. Vast cost opportunities and greenhouse gas emission reduction could result from replacing conventional cooking fuel and chemical fertilizers with organic fertilizer, contributing to the local circular economy. Eventually, the study proposes and discusses a self‐resilient bio‐energy model comprising energy demand fulfillment, sustainability, and a circular economy for rural India. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Changes in the approach to using waste as resources will be a necessity in the coming years. It is due to the transformation of the linear economy into a circular model and many regulations concerning waste management in the European Union countries. The article deals with the important issues of segregation and management of biodegradable waste, which are still unused energy potential. The aim of the study was to investigate the amount of this fraction of waste generated by sample households as well as the problems and barriers related to their storage and collection. The article takes into account the economic, environmental and social conditions that constitute the basis of sustainable development and are very significant for the idea of the circular economy. The minimizing and proper management of the fraction of municipal and biodegradable waste could achieve a greater economic benefits with simultaneous benefits for the environment, protecting its components and human health. [ABSTRACT FROM AUTHOR]

Wind and solar power are already the major pillars of renewable power generation in Germany and will become even more dominant in the future. At the same time, dispatchable power plants phasing out. The expected increase of fluctuations in the residual load could be partial balanced by flexible bioenergy. However, there is currently no assessment approach for quantifying the systemic GHG impacts for flexible bioenergy generation. Based on the merit order concept, we develop an empirical approach to systemically assess the GHG emissions impact for electricity generated by flexible bioenergy plants. We estimate price response functions using the historical data of market prices and feed-in time series for the different forms of dispatchable non-renewbale dispatchable generation (NRDG). By calculating the expected NRDG based on these functions, and using specific emission factors, we are able to estimate the net impact for a switch from invariable to flexible bioenergy generation. The calculated net impact ranges from −20 to −36 g CO 2eq per kWh, which is equivalent to a benefit of −10% to −18% respectively for an average carbon footprint of 200 g CO 2eq per kWh. The calculation tools are written in Python and freely accessible on ZENODO and GitLab. [Display omitted] [ABSTRACT FROM AUTHOR]

• Biogas industry is an important part of Polish bioeconomy. • Anaerobic digestion of sewage sludges enables new added-value bioproducts to be obtained. • Eco-innovative fertilizers developed and produced from valorized sludges. • Optimized bio-treatment of eutrophic digester liquors is necessary and advantageous. • Elaborated novel biotechnologies ensure closing the organic waste management cycles. Bio-based solutions are expected to ensure technological circularity in priority areas such as agriculture, biotechnology, ecology, green industry or energy. Although Poland, unlike the other EU member states, has not yet adopted a precise political strategy to promote bioeconomy, it has taken several actions to enable smart, sustainable and inclusive growth. This goal can be achieved by developing selected bioeconomy-related areas such as the biogas industry together with novel technologies implemented to optimize treatment of municipal sewage and management of organic solid waste. Here, the relatively strong status of the Polish biogas sector is presented. The widely used practice of sewage sludge biomethanation has led to construction of numerous complex installations combining biological wastewater treatment plants with anaerobic digesters. Based on physico-chemical processing of biostabilized sludges, a novel method for efficient granulated soil fertilizer production is elaborated, in line with the concept of circular economy and the notion of "waste-to-product". It is also shown that anaerobic fermentation of sewage sludges can be optimized by co-digestion with properly selected co-substrates to increase bioprocess yield and improve the resultant digestate fertilizer quality. The problem of post-fermentation eutrophic sludge liquors, environmentally hazardous waste effluents requiring proper treatment prior to discharge or field application, is addressed. Attempts to optimize biological treatment of digestate liquors with complex microbial consortia are presented. The Polish innovations described show that the "zero waste" path in circular bioeconomy may bring advantageous results in terms of transformation of waste materials into commercial, added-value products together with recovery of water resources. [ABSTRACT FROM AUTHOR]

Renewable energy can be used from several natural sources, which are capable of wind, sun, water, geothermal springs, or biomass. Energy from these sources is clean, safe and inexhaustible. The use of alternative sources is becoming part of all realistic scenarios and promotes sustainable development and energy security in Europe as well. Renewable energy sources form a relatively significant part of primary energy sources in many countries. Thanks to the undeniable advantages of their use, they form another higher share of combined energy production in Slovakia. In addition, the correct location of renewable energy sources can be a key element in the development of individual regions, which can contribute to achieving better social and economic cohesion in the country. Given these obvious environmental and economic benefits, efficient use of renewable energy sources is receiving increasing attention and support from responsible officials and the general public around the world, including Slovakia. The main goal of this paper was to evaluate the use of renewable resources in Slovakia with a focus on biogas plants. We also evaluate the position of Slovakia within the EU in this area and find out what is the current situation of biogas plants in Slovakia. [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]

Acquiring data from biogas plants can be done by accessing the data stored in the programmable logic controller (PLC) of the biogas plant, which is responsible for issuing control commands to the hardware of the plant. Eight plants of three different manufacturers, with a total of 1370 data points, were analyzed to find similarities which could lead to a reliable but manufacturer‐independent readout of sensor and control values. The expectation was plants of the same vendor being very similar but analysis showed that only minor similarities exist between plants of the same manufacturer. Even less similarities are found when it comes to plants from different manufacturers. [ABSTRACT FROM AUTHOR]

The two‐year monitoring (732 days) of operational methane emissions from pressure relief valves of the gasholders from an agriculture biogas plant is presented. The monitoring aimed at the identification of major factors influencing the emissions and the effect of mitigation measures deduced from the results. The determined emission factors from the valves of both gastight covered digesters are 1.8 and 0.6 % CH4 loss for the first and second year of investigation, respectively. The emission rates strongly depend on seasonal factors like (fast) changes in ambient air temperature as well as the capacity utilization of the combined heat and power and the operation of the gasholders. The implemented mitigation measures significantly reduced the measured methane emissions in the second year of the investigation. [ABSTRACT FROM AUTHOR]

Abstract Flexible power provision from biogas can significantly contribute to energy systems with high shares of renewables. However, the characteristics and demands for this flexibility are not clearly defined or measured. In this paper eight indicators are defined to shape "flexibility" and perform a downstream investigation of eight research projects focusing on flexible energy provision of biogas plants. The indicators are structured in three dimensions (1) velocity (ramps) by which the system can be modulated, (2) power range (bandwidth) and (3) duration for specific load conditions. Based on these indicators bottlenecks for the flexibility potential were identified. One crucial result shows that short-term flexibility of biogas plants is mainly driven by properties of the combined heat and power unit (velocity and bandwidth). The long-term flexibility depends mainly on gas storage, mode of operation and ability for modulation of the target gas production. Highlights • Development of eight indicators to measure flexibility performance of biogas plants. • Application of flexibility indicators to nine research projects. • Sensitivity analysis for flexibility indicators based on a simulated biogas plant. • Interpreting and explaining interactions of flexibility factors and the developed indicators. • Identifying bottlenecks and trade-off for flexibilization of biogas plants. [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]

The introduction of biogas plants is a promising way to recycle organic wastes with renewable energy production and reducing greenhouse gas. Application of anaerobic digestate as a fertilizer reduces the consumption of chemical fertilizers. In this study, the survival of pathogenic bacteria and plant growth promoting bacteria (PGPB) in two full‐scale biogas plants operated at mesophilic condition were investigated. Feedstock and anaerobic digestate samples were collected from biogas plants and bacteria load in samples were detected using standard dilution plate method. Pathogenic bacteria were reduced to not detected level through mesophilic digestion tank except for Campylobacter. However, it could be reduced by 98.7% through a sterilization tank. Bacillus was detected at 8.00 and 7.81 log10 CFU/g dry matter in anaerobic digestates, and it was also resistant to sterilization tank. Bacillus spp. is considered to be the safe bacteria that hold remarkable abilities for promoting plant growth. The results showed that treatment at biogas plants is effective to reduce pathogenic bacteria in dairy manure, and sterilization could further reduce the sanitary risks of pathogenic bacteria relating to anaerobic digestate application. Anaerobic digestates could also be utilized as bio‐fertilizer as the high load of plant growth promoting bacteria. [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]

For flexible power generation of biogas plants and effective heat utilization, efficient heat storage technologies will play a decisive role. For this purpose, a process is being developed in the ThermoFlex project, based on controlled operation of a secondary digester in thermophilic temperature ranges after a mesophilic main digester. This allows effective, flexible heat storage in the secondary digester for digester heating and external heat utilization at an acceptable temperature level without additional storage. The process biology of the secondary digester tolerates controlled temperature variations. An overview of the application potential and design of the ThermoFlex process is given. Batch and semicontinuous fermentation tests at various temperatures are described. Flexibilization strategies for biogas plants are the key to their success in the energy transition to renewable sources. In the ThermoFlex process, controlled operation of a thermophilic secondary digester following a mesophilic main digester allows effective, flexible heat storage in the secondary digester for digester heating and external heat utilization without disturbing its process biology. [ABSTRACT FROM AUTHOR]

Abstract: Aquatic macrophytes are important components of aquatic habitats. However, the overgrowth of aquatic plants can cause severe problems for the management of bodies of water. As a result, these plants must be removed and disposed of as waste. However, the usage of this biomass as a substrate in biogas plants would appear to be more beneficial. The present study shows the advantages and barriers to the use of harvested aquatic biomass for energy production in Germany. The results cover several aspects of this issue, such as the question of biomass potential, the quality of the harvested aquatic plants, and ensiling for the purpose of conservation for anaerobic digestion. In addition, the social aspects of the de‐weeding in bodies of water are discussed. [ABSTRACT FROM AUTHOR]

China has a long history of utilizing biogas technology for the treatment of waste and the production of energy. This paper reviews the development and technology of the three types of biogas digesters used in China: household-scale digesters, biogas septic tanks, and biogas plants for the treatment of municipal, industrial, and agricultural waste. The structure of household-scale digesters is simple and practical; the basic type is the fixed-dome digester, also called the hydraulic digester. The biogas septic tank for sewage treatment is a combination of the traditional digester, an anaerobic filter, and a facultative filter. Biogas plants apply several different processes depending on the type of waste treated. The treatment of municipal waste biogas is conducted using the completely stirred tank rector (CSTR). The upflow anaerobic sludge blanket (UASB) is the most common technology used in the anaerobic treatment of industrial wastewater, followed by the CSTR and the anaerobic contact (AC) process. The treatment of agricultural waste mainly employs traditional hydraulic digesters, while newer biogas plants use advanced anaerobic processes such as CSTR and UASB as well as upflow solids reactors (USR) and upflow blanket filter (UBF) reactors. Biogas plants for agricultural waste are classified as small, medium, large and super large based on the scale of biogas production and digester volume. Although small-scale biogas plants are the most common, large-scale biogas plants produce the largest biogas output. With the changes associated with socio-economic development, the growth of household-scale digesters will slow down in the future. As central sewage treatment networks become more widespread, biogas septic tanks will be confined to villages and small towns. The development of biogas plants holds the most growth potential for the future. [ABSTRACT FROM AUTHOR]

Recently, there is a growing pressure on a rapid construction of agricultural biogas plants, particularly in the Czech-Polish border region. It is an area with large expanses of agricultural land which can serve to supply biogas plants with biomass. This strategy should contribute to harmonize the common agricultural policy of the European Union. A need for qualified operators of these stations on this territory is also increasing. Therefore we first include a demonstration of an education program for students in the field of agricultural waste anaerobic fermentation and biogas production. We present here the first part of an innovative approach which we use in the teaching program "Physico-technical Measurements and Computer Technology" at the Faculty of Science at the University of Hradec Kralove and also in the education of internshipers from the Faculty of Natural Sciences and Technology at the University of Opole. There are requirements to fulfil labour market expectations and to make this subject more attractive for the students. Students' theoretical and practical preparation constitutes a comprehensive source of knowledge and skills required in a real life job. Joined theoretical and practical knowledge gained by students, reinforced by the skills developed during task analysis followed by their solution, provides the future graduate higher quality abilities and better position in the labour market. [ABSTRACT FROM AUTHOR]

Biogas-storage- and Biogas-filling-facilities - Approvals for construction products and techniques In accordance with the building and water regulations, assessments of fitness for use pursuant to the Building Codes can be issued for construction products and techniques used in storage and filling facilities of biogas plants since September 2015. The article explains which building and water regulations apply to construction products and techniques intended for such use. The requirements in both legislative areas have considerable effects on the characteristics of construction products and techniques intended for contact with fermentation substrates and fermentation residues. In particular, the water regulations set out strict requirements for construction products intended for use in such facilities, which are reflected in high verification requirements for functional reliability and fitness for use. The paper focuses on general aspects, which apply to all approval elaboration and granting processes for construction products and techniques used in the before-mentioned areas of biogas plants. More specific aspects of approval elaboration will also be addressed, using the example of selected construction products and techniques. The article provides guidance for product manufacturers and for qualified planning and design. It also explains certain specific provisions to be met by specialised firms and qualified professionals within the meaning of water legislation and by operators of biogas storage and filling facilities. [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]

Slovakia committed to the objectives related to the mitigation of climate change's pace. The most important acts include reducing energy consumption and increasing the share of renewable energy in gross final energy consumption of the country. Regions are challenged by a fundamental transformation of energy. The main aim of this paper was to evaluate the use of renewable energy sources in Slovakia, as well as the procedural and economic side of support mechanisms allowing progress in the use of renewable energy sources. The secondary aim was to economically assess the impact of support schemes for the effectiveness of investments and make recommendations on renewable energy use for the next period based on an example of a biogas plant in Slovakia. Slovakia has experienced the development of biogas installations after the year 2009. By 2013, Slovak market significantly promoted investments in biogas plants, but in 2014, there was a downturn in the installation of new ones. A database for the analysis was obtained from real data of a specific biogas plant in Slovakia. Results of the analysis declare that financial support mechanisms from the country and the EU are a major determinant in the development of biogas plants in Slovakia with a positive impact on important economic indicators of effectiveness. This process will also support the achievement of the objectives of Target 2020. [ABSTRACT FROM AUTHOR]

Experiences of numerous full-scale biogas plants on spontaneous foam formation were evaluated. Focus was laid on the feedstock mix, the causes of foaming, and control strategies. Mostly, the main digester was affected, but excessive foam formation in the post digester was found as well. The feedstock mix was stated as the main cause of foam formation followed by process troubles, abrupt degassing, temperature changes, and changes in viscosity. In the feedstock of plants affected by foaming, manure, cereals, sugar beets, and cosubstrates were used most often. Successful control strategies were gathered and categorized into seven groups: emergency measures, application of antifoam additives, avoidance of foam-forming substrates, prevention of process upsets, changes of physicochemical conditions, optimization of mixing, and installation of technical equipment against foam formation. [ABSTRACT FROM AUTHOR]

Vancomycin-resistant enterococci (VRE) and methicillin-resistant staphylococci (MRS) were detected in two mesophilic German biogas plants (BGPs) using selective pre-enrichment methods combined with cultivation on CHROMagar media and antibiotic resistance gene screening. Genetic fingerprinting and 16S rRNA gene sequencing showed the presence of enterococci isolated by the VRE selective cultivation (67 isolates) in input and output samples of BGPs. In contrast, MRS (44 isolates) were detected in input, but in none of the output samples. Enterococcus isolates showed highest 16S rRNA gene sequence similarity (>99.8%) to E. lemanii, E. casseliflavus/E. gallinarium or E. devriesei/E. pseudoavium/E. viikkiensis and carried vanA, vanB and/or vanC1 genes. Enterococcus faecium and E. faecalis VRE were not detected, but isolates closely related to those species (>99.9% 16S rRNA gene sequence similarity) were detected by the MRS selective cultivation methods. Staphylococcus isolates shared highest 16S rRNA gene sequence similarity (>99.9%) with S. haemolyticus, S. lentus and S. sciuri and carried mecA genes. Methicillin-resistant S. aureus (MRSA) were not detected. In summary, manure from livestock husbandry contained both, VRE and MRS. VRE were also detected in output samples, indicating that enterococci with vancomycin resistance genes could be release into the environment by the application of BGP output material as biofertilizers. [ABSTRACT FROM AUTHOR]

The application of manure, typically harboring bacteria carrying resistance genes (RGs) and mobile genetic elements (MGEs), as co-substrate in biogas plants (BGPs) might be critical when digestates are used as fertilizers. In the present study, the relative abundance of RGs and MGEs in total community (TC-) DNA from manure, fermenters and digestate samples taken at eight full-scale BGPs co-fermenting manure were determined by real-time PCR. In addition, the bacterial community composition of all digestates as well as manure and fermenter material from one BGP (BGP3) was characterized by 454-pyrosequencing of 16S rRNA amplicons from TC-DNA. Compared to respective input manures, relative abundances determined for sul1, sul2, tet(M), tet(Q), intI1, qacE1, korB and traN were significantly lower in fermenters, whereas relative abundances of tet(W) were often higher in fermenters. The bacterial communities in all digestates were dominated by Firmicutes and Bacteroidetes while Proteobacteria were low in abundance and no Enterobacteriaceae were detected. High-throughput sequencing revealed shifts in bacterial communities during treatment for BGP3. Although in comparison to manure, digestate bacteria had lower relative abundances of RGs and MGEs except for tet(W), mesophilic BGPs seem not to be effective for prevention of the spread of RGs and MGEs via digestates into arable soils. [ABSTRACT FROM AUTHOR]

A synthetic DNA fragment containing primer binding sites for the quantification of ten different microbial groups was constructed and evaluated as a reliable enumeration standard for quantitative real-time PCR (qPCR) analyses. This approach has been exemplary verified for the quantification of several methanogenic orders and families in a series of samples drawn from a mesophilic biogas plant. Furthermore, the total amounts of bacteria as well as the number of sulfate-reducing and propionic acid bacteria as potential methanogenic interaction partners were successfully determined. The obtained results indicated a highly dynamic microbial community structure which was distinctly affected by the organic loading rate, the substrate selection, and the amount of free volatile fatty acids in the fermenter. Methanosarcinales was the most predominant methanogenic order during the 3 months of observation despite fluctuating process conditions. During all trials, the modified quantification standard indicated a maximum of reproducibility and efficiency, enabling this method to open up a wide range of novel application options. [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]

In recent years, the increasing number of biogas plants in operation has also led to a considerable rise in fermentative substrates, which are now widely used as agricultural fertilizers. The impact on earthworm fauna of using biogas digestate as a fertilizer has yet to be sufficiently researched. At two different tests sites, the short-term (four months after fertilization) and longer-term (three-year test period) influence of using fermented residues as a fertilizer was examined on earthworm density, biomass and community composition compared to using traditional fertilizers (cattle and pig slurry, chemical fertilizers as well as an unfertilized control). The crop grown was maize ( Zea mays L.). Applying biogas digestate and slurry had a positive overall impact at both sites on earthworm density and biomass. Observing different fertilization regimes in the short term, the significantly highest earthworm density was seen where slurry had been applied. In the treatments with digestate and conventional slurry, earthworm biomass differed significantly in comparison with chemical fertilization and the untreated variant. After three years, earthworm biomass in the variants fertilized with conventional slurry and digestate tended to be higher than in the chemical fertilizer and untreated variants. Community composition was strongly influenced by the application of digestate. A decrease in the species Aporrectodea rosea was accompanied by an increase in Aporrectodea caliginosa . The earthworm population was supported equally positively at both sites by the variants with conventional slurry and digestate. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to model the multi-criteria decision problem of identifying the most suitable facility locations for biogas plants under an integrated decision support methodology. Here the Geographical Information System (GIS) is used for measuring the attributes of the alternatives according to a given set of criteria. Measurements are taken in interval form, expressing the natural imprecision of common data, and the Fuzzy Weighted Overlap Dominance (FWOD) procedure is applied for aggregating and exploiting this kind of data, obtaining suitability degrees for every alternative. The estimation of criteria weights, which is necessary for applying the FWOD procedure, is done by means of the Analytical Hierarchy Process (AHP), used jointly with the LLSM-AHP for the estimation of upper and lower bounds for the weights. Then, a combined AHP-FWOD methodology allows identifying the more suitable sites for building biogas plants. We show that the FWOD relevance-ranking procedure can also be successfully applied over the outcomes of different decision makers, in case a unique social solution is required to exist. The proposed methodology can be used under an integrated decision support frame for identifying the most suitable locations for biogas facilities, taking into account the most relevant criteria for the social, economic and political dimensions. [ABSTRACT FROM AUTHOR]

• 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. [ABSTRACT FROM AUTHOR]

Abstract: Increasing shares of intermittent power sources such as solar and wind will require biomass fueled generation more variable to respond to the increasing volatility of supply and demand. Furthermore, renewable energy sources will need to provide ancillary services. Biogas plants with excess generator capacity and gas storages can adapt the unit commitment to the demand and the market prices, respectively. This work presents a method of day-ahead unit commitment of biogas plants with excess generator capacity and gas storage participating in short-term electricity and control reserve markets. A biogas plant with 0.6 MW annual average electric output is examined in a case study under German market conditions. For this biogas plant different sizes of the power units and the gas storage are compared in consideration of costs and benefits of installing excess capacity. For optimal decisions depending on prices, a mixed-integer linear programming (MILP) approach is presented. The results show that earnings of biogas plants in electricity markets are increased by additional supplying control reserve. Furthermore, increasing the installed capacity from 0.6 MW to 1 MW (factor 1.7) leads to the best cost–benefit-ratio in consideration of additional costs of excess capacity and additional market revenues. However, the result of the cost–benefit-analysis of installing excess capacity is still negative. Considering the EEG flexibility premium, introduced in 2012 in the German renewable energy sources act, the result of the cost–benefit-analysis is positive. The highest profit is achieved with an increase of the installed capacity from 0.6 MW to 2 MW (factor 3.3). [Copyright &y& Elsevier]

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]

Abstract: The need to calculate greenhouse gas emissions (GHG emissions) has become more or less ubiquitous throughout the economy, both in public and private areas. As present, a diverse number of calculation methods are available for preparing GHG emission inventories. However, several questions remain unresolved since there is currently no uniformity regarding how to define ‘the waste management industry’. The present paper focuses on these problems. The objectives are: first, to provide an approach for setting up a GHG emission inventory for the waste management sector; and second, to consider the sensitive issue of setting system boundaries when establishing a GHG emission inventory and also to emphasise the considerable need for caution when doing so. The approach elaborated here is based on a comprehensive literature analysis and on a comparison of existing GHG emission calculation approaches, particularly with regard to the waste management sector. Since the issue of selecting system boundaries for establishing GHG emission inventories, particularly in the waste management sector, is a very special and difficult topic, it receives considerable attention in the present paper. This means that the system boundaries and interfaces with respect to three illustrative areas are considered in some depth. These areas are collection and transport, incineration and co-combustion, and biogas plants. [Copyright &y& Elsevier]

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]

Biogas plants gain worldwide increasing importance due to several advantages. However, concerning the equipment most of the existing biogas plants are low-tech plants. E.g., from the point of view of instrumentation, control and automation (ICA) most plants are black-box systems. Consequently, practice shows that many biogas plants are operated sub-optimally and/or in critical (load) ranges. To solve these problems, some new biogas plants have been equipped with modern machines and ICA equipment. In this paper, the authors will show details and discuss operational results of a modern agricultural biogas plant and the resultant opportunities for the implementation of a plant-wide automation. [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 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]

Abstract: A soil microcosm experiment was performed to assess (1) the C- and N- turnover of residues from biogas plants in soils in the presence of three earthworm species (Lumbricus terrestris, Aporrectodea longa and Aporrectodea caliginosa) and (2) the resulting changes in soil chemical and microbiological properties when using these residues as fertilizer in comparison to conventional slurry. Earthworms were exposed in soils, fertilized with an equivalent amount of 120kg of NH4-N ha−1 from: (1) conventional cattle slurry and (2) a fermented residue derived from cattle slurry, grass (silage) and maize. Additional treatments without slurry and earthworms were used as controls. There was considerable evidence that soils fertilized by fermented slurry comprised fewer amounts of readily available nutrients for microbial C and N turnover. We observed significant stimulation of microbial biomass, basal respiration and nitrification in treatments with conventional slurry, especially in the presence of earthworms. However, the stimulation of microbial activity by manure and earthworms were significantly lower in treatments with fermented slurry. Moreover, the results showed clear interactions between different earthworm species and manures. While the biomass of the anecic species (L. terrestris and A. longa) increased in both slurry treatments, the biomass of A. caliginosa (endogeic) decreased, with a significantly stronger biomass decline in treatments with fermented slurry. The metabolic quotients revealed microbial stress metabolism in fermented slurry treatments, predominantly in treatments with A. caliginosa. We conclude that particularly A. caliginosa and soil microorganisms competed for labile C sources in treatments with fermented slurry. An application of these residues as fertilizer might result in a reduction of microbial activity in agricultural soils and in a decline of endogeic earthworms. [Copyright &y& Elsevier]

Agricultural biogas plants based on energy crops gain more and more importance because of numerous energetic, environmental and agricultural benefits. In contrast to older biogas plants, the newest generation of biogas plants is equipped with modern ICA equipment and reliable machines/engines. In this paper, the authors present technical details and operational results of a modern full-scale agricultural biogas plant using energy crops. [ABSTRACT FROM AUTHOR]

In recent years manure-based biogas plants (MBBP) have won more and mere importance, because of the numerous ecological advantages. The processes are similar to processes, which have been well known for many decades in anaerobic wastewater/sludge treatment. As a result of technical progress and permanently rising prices for non-renewable energy, MBBPs have become more and more economically reasonable. Because of the economies of scale law more and more larger MBBPs are being built (250-2000 kWel). With regard to investment costs, reactor volumes and complexity etc., these (centralized) plants are comparable with small wastewater treatment plants (WWTP). Consequently, as actually in the case of the small WWTPs a rising use of instrumentation, control and automation (ICA) for larger MBBPs can be observed. [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]

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. [Display omitted] • 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. [ABSTRACT FROM AUTHOR]