Biogas Plants Research Articles

A Closed-Loop Economy in the Meat Industry for Generating Alternative Energy from Biogas Plants

This study deals with the concept of a closed-loop economy in the meat industry through the use of animal by-products in biogas plants for electricity generation processes. The purpose of the study was to identify the volume of by-products from the slaughter of cattle and pigs, how the by-products are managed, and the efficiency of their use in biogas plants for electricity production processes. The analyses used data from the Central Statistical Office, the Chief Veterinary Inspectorate, and information obtained from the Polish Agency for Enterprise Development. Studies from the literature on closed-loop economies and bioeconomies were also a valuable source of information. Based on case studies, this paper also presents examples of a closed-loop economy in meat companies. In the area of pork, poultry, and beef livestock production, the analysis covered the years 2004–2022, while in the area of the production and use of meat industry by-products, the data came from 2017–2022. The study shows that reducing the production of waste in the meat industry and the reuse and recycling of waste are important parts of a closed-loop economy. In meat companies, waste from slaughtering animals can be properly managed, either by processing it into animal feed or by using it in biogas plants to generate electricity or heat. Taking into account the number of by-products from cattle and pig slaughter in the country, biogas plants could produce approximately 95,232 MW of electricity per year, which constitutes approximately 4.3% of the energy intensity of the meat industry in Poland.

Pre-Commercial Demonstration of a Photosynthetic Upgrading Plant: Investment and Operating Cost Analysis

Pig farms have been identified as one of the most important sources of greenhouse gas emissions. This study demonstrates the production of vehicle biomethane in a demonstration prototype plant based on photosynthetic upgrading technology, where the CO2 and H2S present in biogas are consumed by a microalgae culture. The information collected during the prototype construction allowed for an assessment of the capital and operating costs of this novel biogas upgrading technology with other conventional systems. With this objective, the costs of the equipment comprising the biogas cleaning and purification system were calculated considering a biogas flow rate of 5 m3 h−1, corresponding to a small–medium biogas plant and an average pig farm size. The sustainability and competitiveness of the algae upgrading system and the low capital and operating costs vis à vis other upgrading technologies were proven. With a net energy production of 687 kWh day−1 and an annual profit of 30,348 € in a 3500 head pig farm, this technology can be easily installed in livestock farms, increasing the benefits and reducing the carbon footprint.

The Influence of Temperature on Rheological Parameters and Energy Efficiency of Digestate in a Fermenter of an Agricultural Biogas Plant

This investigation specifically aims to enhance the understanding of digestate flow and mixing behavior across typical temperatures in bioreactors in agricultural biogas plants, facilitating energy-efficient mixing. Experimental tests confirmed that digestate exhibits non-Newtonian characteristics, allowing its flow behavior to be captured by rheological models. This study validated that digestate rheology significantly varies with temperature, which influences flow resistance, mixing efficiency and overall energy requirements. Two rheological models—the Bingham and Ostwald models—were applied to characterize digestate behavior, with the Ostwald model emerging as the most effective for Computational Fluid Dynamic (CFD) simulations, given its balance between predictive accuracy and computational efficiency. Specifically, results suggest that, while three-parameter models, like the Herschel–Bulkley model, offer high precision, their computational intensity is less suitable for large-scale modeling where efficiency is paramount. The small increase in the accuracy of the shearing process description does not compensate for the significant increase in CFD calculation time. Higher temperatures were found to reduce flow resistance, which in turn enables increased flow rates and more extensive mixing zones. This enhanced mass transfer and mixing potential at elevated temperatures are especially pronounced in peripheral areas of the bioreactor, farthest from the agitators. By contributing a model for rheological behavior under realistic bioreactor conditions, this study supports the optimization of energy use in biogas production. These findings emphasize that temperature adjustments within bioreactors could serve as a reliable control strategy to maintain optimal production conditions while minimizing operational costs.

Synthesis of encapsulated nanofertilizer from biogas plant digestate

Synthesis of encapsulated nanofertilizer from biogas plant digestate

Techno-economic analysis of a biogas power plant: Moving to sustainable energy supply and green environment through waste management

The feasibility of establishing an anaerobic digestion power plant for producing electricity, heat, and bio-fertilizer using a combined heat and power system using municipal solid waste in Sanandaj has been designed and simulated. The optimal condition for biogas production will be identified using an experimental design, and subsequently, modeling under optimal conditions was performed using Aspen Plus. The anaerobic digestion process was simulated under thermophilic conditions at a temperature of 55 °C, pressure of 1 atm, and retention time of 15 days. The daily biogas production amounted to 32,174 m3 from 380 tonnes of municipal solid waste. The daily production of electricity and heat was 2.9 MW and 3.3 MW, respectively. The daily production of bio-fertilizer was 48 tonnes. The electricity produced can meet approximately 3 % of Sanandaj's total demand. In addition to energy production from waste, the economic evaluation indicated that the project's net present value over a 20-year operational period was approximately 6333,333 €, demonstrating the project's economic viability. Furthermore, establishing this power plant will prevent 85,023 tonnes of CO2 annually. The results indicated the effectiveness of the designed plant in replacing power generation with fossil fuel and reducing greenhouse gas emissions.

A methodical approach to the grounding of the raw material base for biogas plants

A methodical approach to the grounding of the raw material base for biogas plants

Holistic approach to energy storage management aspects in sustainable community

Energy management is nowadays key topic for synchronic operation of renewable sources of energy and their recipients. Contemporary national electrical power grid systems more often cannot supply efficiently electrical energy and cannot receive energy produced by renewable sources. The common approach to the problem is to meet energy demands supplying from electrical grid and renewable power sources with energy storage feature. From the other side, off-grid solutions based on the co-generation biogas plants are commonly aimed on small local communities as power supply supported by renewable energy systems like photovoltaic (PV) systems, wind power plants or small water plants with energy storage to support self-consumption of electrical energy. Integration of intermittent renewable power sources, such as solar, wind and biogas plant, increases the difficulty of managing the electricity grid and maintaining the balance of electricity supply and demand, especially in small communities. The holistic approach to the energy storage management takes all above aspects and presents the concept where municipal waste is used to produce energy in biogas plant supported by PV systems and community shared electrical energy storage to provide uninterrupted power supply. The study also presents how energy storage management can be used in whole process to adjust the size and manage energy supply and demand within the community based on energy self-consumption optimization. It is also shown that by utilizing municipal waste produced by the community we can meet the goals of circular economy and sustainable development of local communities as the waste will be used in full without necessity of recycling it outside the community. The novelty of the study is the foundation for energy storage capacity and renewable energy sources size evaluation to balance energy management process without the need of on-grid power supply and with use only municipal biodegradable waste for biogas fuel supply and solar energy for energy production.

Evaluation of multi–hydrogen production for Afyon biogas plant from excess methane and by–product hydrogen sulfide through desulfurization process

This study presents a detailed computational simulation of a hybrid hydrogen production system that integrates steam methane reforming (SMR) and hydrogen sulfide (H₂S) electrolysis, coupled with waste heat recovery, at the Afyon Biogas Power Plant (ABP). The plant operates with a capacity of 4000 kW and an exhaust gas temperature of approximately 767 K, converting 55 % of the biogas to energy, constrained by the limitations of both the turbine and biogas plant operations. Despite these constraints, a methane yield of up to 75 % from biomass is achievable. The surplus methane is converted into blue hydrogen via SMR, while H₂S, a byproduct of biogas production, undergoes electrolysis to generate green hydrogen. Additionally, gray hydrogen is separated and stored during the biogas production process. The system achieves a hydrogen production rate of 0.061 kg/s through optimization, comprising 91.4 % blue hydrogen, 8.18 % gray hydrogen, and 0.41 % green hydrogen. The energy and exergy efficiencies of the primary system are calculated to be 26.23 % and 22.99 %, respectively. The integration of waste heat recovery enhances these efficiencies to 76.21 % and 42.96 %. A techno-economic analysis indicates that the cost of electricity is 0.04644 $/kWh, while the average hydrogen production cost is 2.05 $/kg. The total investment cost (TIC) amounts to 21,177,230 $, with an estimated annual revenue of 4,702,000 $, yielding a payback period of 4.405 years. This study demonstrates the efficiency and economic feasibility of hydrogen production from waste products at the biogas plant, underscoring the viability of the proposed investment.

Estimation and Control of WRRF Biogas Production

The development of resource-efficient digital technologies is a critical challenge in the wastewater sector. This industrial case study, conducted in collaboration with the Veas Water Resource Recovery Facility in Norway, focused on creating data pre-processing methods and resource-efficient control strategies. Using data from the Veas biogas plant, dynamic models were developed to compare control outcomes. The primary objective was to maximize biogas production and hot water usage while maintaining optimal temperature and hydraulic retention time by adjusting inlet sludge and hot water flow rates. Sequential operations were approximated as continuous operations using a 30-min moving minimum/maximum for bimodal data and a 2-h moving average for noisy data. The data-driven dynamic models achieved an accuracy of up to R2 of 0.85. The control strategy, which included one feedback controller, one ratio controller, and flow rate restrictions, was compared to real production data (baseline) and tested across six scenarios. The best improvement over the baseline scenario resulted in a 3% increase in total biogas production, a 6% increase in total organic loading, a 13% increase in hot water use, and a one-day reduction in hydraulic retention time. Future work should focus on control studies using extended datasets and nonlinear models.

Microbial diversity and biosafety judgment of digestates derived from different biogas plants for agricultural applications

The composition of microbial communities is the key to effective anaerobic digestion (AD). The microbiome driving the AD process has been extensively researched, whereas the influence of specific substrates on the microbiome of digestate remains insufficiently investigated. Digestate has considerable potential for use in soil fertilization and bioremediation, therefore its biological safety should be monitored. Moreover, the knowledge about the composition of microbial communities and their interconnections in digestate should be extended, due to the impact on soil microbiota and its functionality. The aim of this study was a comprehensive assessment of the (1) sanitary quality, (2) core microbiome, and (3) microbial interactions in digestates collected from three full-scale agricultural biogas plants, with particular emphasis on their applicability from the perspective of the resident microbiota. Analyzed samples of digestate were derived from various substrates used for AD, including plant- and animal-based materials, and industrial waste. The study demonstrated that the phyla Bacillota, Bacteroidota, and Cloacimonadota were the most dominant in digestates regardless of the composition of the processed substrates, however, member composition at the genus level differed significantly between samples. In addition, we observed that microbial genera belonging to the less prevalent phyla play an integral role in the forming of microbial community interactions. Dominant microbial taxa with broad metabolic capabilities, potentially improving soil quality and functionality, have been identified. Moreover, we confirmed, that digestate samples were free of analyzed pathogenic bacteria and parasites. The study results indicate that digestate may have an immense fertilizing and bioremediation potential that has not been fully availed of to date.

Comparative analysis of manure treatment scenarios on climate change and eutrophication in the Baltic Sea

This study conducted a life cycle assessment (LCA) of manure management, identifying transportation as a major contributor to global warming and freshwater eutrophication impacts. Transporting substrates to the biogas plant was the main hotspot, highlighting a critical area for improvement. The findings emphasize the importance of method selection in geographically dependent assessments, especially in the Baltic Sea region. Characterization factors specific to Sweden revealed higher environmental impact values than those produced by the ReCiPe method, underscoring the need for regional differentiation in LCA. By optimizing manure management practices and enhancing nutrient distribution, impacts on both climate change and eutrophication can be significantly reduced, thereby lowering nutrient flow to the Baltic Sea. Combining these optimizations with transportation impact reductions further amplifies these environmental benefits, demonstrating that geographically tailored approaches in LCA offer essential insights for managing regional-scale effects.

The Analysis of Geospatial Factors Necessary for the Planning, Design, and Construction of Agricultural Biogas Plants in the Context of Sustainable Development

This spatial analysis focuses on the relevant elements regarding the use of renewable energy sources, in particular, biogas, taking into account sustainability. The characteristics of the processes of biogas formation are presented, including the technological and biological aspects of its production. The issues of agricultural biogas plant profitability are discussed using examples from Poland, analyzing the economic and financial aspects of investing in this type of plant. Geospatial analysis supported by geographic information systems (GISs) looked at factors affecting the relief of the land and also the analysis of local plans or zoning decisions for the selected site. In addition, distance relationships and geological aspects taking into account terrain, landslides, and forestation, as well as hydrological aspects relating to flood and flooding hazards, were examined. It analyzed the availability of utility networks and proximity to road infrastructure. It was also examined that the proposed project will not have a negative impact on environmental protection. The analyzed site meets favorable conditions for the construction of the proposed project, and the conclusion drawn from this study is to emphasize the importance of integrating renewable energy sources with information systems to achieve sustainable development.

Application of GIS in Introducing Community-Based Biogas Plants from Dairy Farm Waste: Potential of Renewable Energy for Rural Areas in Bangladesh

Dairy production is one of the most important economic sectors in Bangladesh. However, the traditional management of dairy cow manure and other wastes results in air pollution, eutrophication of surface water, and soil contamination, highlighting the urgent need for more sustainable waste management solutions. To address the environmental problems of dairy waste management, this research explored the potential of community-based biogas production from dairy cow manure in Bangladesh. This study proposed introducing community-based biogas plants using a geographic information system (GIS). The study first applied a restriction analysis to identify sensitive areas, followed by a suitability analysis to determine feasible locations for biogas plants, considering geographical, social, economic, and environmental factors. The final suitable areas were identified by combining the restriction and suitability maps. The spatial distribution of dairy farms was analyzed through a cluster analysis, identifying significant clusters for potential biogas production. A baseline and proposed scenario were designed for five clusters based on the input and output capacities of the biogas plants, estimating the location and capacity for each cluster. The study also calculated electricity generation from the proposed scenario and the net greenhouse gas (GHG) emissions reduction potential of the biogas plants. The findings provide a land-use framework for implementing biogas plants that considers environmental and socio-economic criteria. Five biogas plants were found to be technically and spatially feasible for electricity generation. These plants can collectively produce 31 million m3 of biogas annually, generating approximately 200.60 GWh of energy with a total electricity capacity of 9.8 MW/year in Bangladesh. Implementing these biogas plants is expected to increase renewable energy production by at least 1.25%. Furthermore, the total GHG emission reduction potential is estimated at 104.26 Gg/year CO2eq through the annual treatment of 61.38 thousand tons of dairy manure.

Optimizing Methane Recovery for Fuels: A Comparative Study of Fugitive Emissions in Biogas Plants, WWTPs, and Landfills

How accurate are current estimation methods for fugitive methane emissions in methane-producing facilities, and how do they vary across biogas plants, wastewater treatment plants (WWTPs), and landfills? Based on this, the hypothesis posited in this study is that current methods significantly underestimate methane emissions, particularly in WWTPs and biogas plants, due to limitations in accounting for recovered methane and the reliance on general parameters such as the oxidation factor. To test this, a comparative analysis was carried out involving 33 biogas plants, 87 WWTPs, and 119 landfills in the Iberian Peninsula, comparing officially recorded data with estimates derived from our own calculations. Our findings confirm the lack of precision in current emission estimation methods, particularly for WWTPs and biogas plants, where factors like the omission of recovered methane lead to underreporting. This study highlights that WWTPs emit the largest amount of methane due to their organic material processing, exceeding emissions from landfills and biogas plants. In contrast, methods for estimating emissions in landfills are found to be more reliable. The results suggest that improving calculation methodologies, especially for WWTPs and biogas plants, as well as enhancing leak monitoring and methane recovery systems, is crucial to reducing the environmental impact of methane-producing facilities.

Research on a New Method of Water Recovery from Biogas Plant Digestate

Digestate is a product with valuable fertilizing properties, remaining after the anaerobic fermentation process. An essential feature of the substance in question is its high water content of up to 97%. To improve the fertilizer value of the digestate, it is necessary to dehydrate it to produce a concentrated product. This paper determined the possibility of dewatering the digestate using an innovative reactor design. The study, conducted on a laboratory scale, used digestate from a Polish biogas plant. The dewatering technique described in the paper is based on the evaporation and condensation of water vapor on the inner surface of the reactor dome. The condensate accumulated on the leach trough and was directed to a storage tank. During the weeks of testing, 11.5 kg of condensate was separated from the initial weight of the digestate (32 kg), with a dry weight of 6.11%. The resulting condensate from dehydration had an average pH value of 9.0 and an average ammonium nitrogen content of 2.07 g∙kg−1. The economic calculations made in the paper allowed for estimating the expected savings associated with the management of digestate in Poland. The research showed the proposed technology’s high potential for dewatering digestate under laboratory conditions.

A life cycle assessment of cover crop ensiling and co-digestion with cattle manure

AbstractCover crops offer a potential biogas feedstock, and to enable continuous operation of the biogas plant, ensiling can be used for biomass preservation. The aim of the present study was to assess the environmental impacts of biogas production at an organic dairy farm for two modelled scenarios: (1) harvesting and ensiling of cover crops and cereal straw and co-digestion with cattle manure, or (2) mono-digestion of cattle manure and direct cover crop soil incorporation. The biogas scenarios were modelled in a consequential LCA in relation to a common baseline without anaerobic digestion, with cover crop soil incorporation and field application of raw cattle manure. Biogas scenarios resulted in decreased global warming impacts of (1) 250 and (2) 120 Mg CO2eq for a 1000-hectare example dairy farm due to substitution of natural gas. However, emissions from ensiling, biogas plant operation, and agronomic effects increased other environmental impacts. Agronomic modelling with the Daisy model showed a crop yield increase of 0.11 Mg DM ha−1 year−1 on a sandy loam soil with cover crop digestion, but also an increase in N leaching of 38% and a decrease in soil C stocks of 8.1 Mg C ha−1 over 100 years relative to the reference. Emissions of VOCs and NOx during ensiling increased ozone formation and negative impacts on human health and ecosystems, although further research is needed to better understand these emissions. In conclusion, this modelling study shows that greenhouse gas emissions can be reduced by using ensiled cover crops for co-digestion with manure when biogas is used to substitute fossil gas, although trade-offs with other environmental categories must be considered.

Use of Apple Pomace for Intensification of Biogas Production in the Anaerobic Digestion of Cattle Manure

The goal of the work is to increase the yield of methane in biogas plants due to the joint methane fermentation of cattle manure with apple pomace. To achieve this goal, the following tasks were solved: the yield of biogas from cattle manure was determined with the addition of apple pomace to the substrate and fermentation in psychrophilic and mesophilic temperature conditions of the biogas plant. Based on the obtained experimental data of fermentation at temperatures of 22±1°C and 36±1°C of the fermenter, the biogas yield was assessed and the rational temperature regime for the operation of the biogas plant was determined. The studies were carried out on a laboratory biogas plant, consisting of a fermenter and a wet-type gasholder. A glass container with a total volume of 3 dm3 was used as a fermenter. The novelty of the chosen topic lies in the fact that the maximum methane output rate was determined under periodic loading of the fermenter, which for the psychrophilic temperature regime is 0.0033 m3/(kg DOM∙day), and in the mesophilic temperature regime mode 4 times more - 0.012 m3/(kg DOM∙day). The significance of the results lies in the fact that based on the results of the dynamics of methane output during periodic loading of the fermenter, it is possible to predict a constant methane output in industrial biogas plants that operate in a quasi-continuous mode, which will be equal to the maximum methane output during periodic loading of the fermenter.

Bioaugmented ensiling pretreatment to improve bioconversion of sweet sorghum: Effect of bio-additives on enzymatic saccharification and biomethane potential

This study proposes a novel strategy to integrate ensiling preservation with pretreatment of sweet sorghum (SS) biomass. Bio-additives, including cellulase, xylanase, liquid anaerobic digestate (LD), and rumen fluid (RF) were applied in ensiling process to improve the silage quality, sugar production by enzymatic hydrolysis, and anaerobic biomethane production of SS. Compared with others additives, LD could alter microbial community compositions and reduce the crystallinity of SS, thus improving ensiling pretreatment performance and achieving the highest reducing sugar yield of 84.73%. The methane production of LD silages was increased by 32.84% compared with the un-ensiled SS, indicating that ensiling pretreatment with LD could be an effective strategy to achieve the trans-seasonal preservation and improving the methane production of SS. Furthermore, taking techno-economic factors into account (energy net income of 96.07 USD/ton), LD additive was recommended for the bioaugmented ensiling pretreatment and downstream methane production of SS, which also contribute to recirculate the liquid digestate from biogas plant.

The biomethane potential for public transport decarbonization in Italian cities

Abstract The transport sector remains heavily reliant on oil products, and it is among those that are considered harder to decarbonize, especially in some specific segments. Considering public transport, there is currently a significant interest in electrifying urban buses, especially for some routes that are well suited for the current characteristics of battery electric buses. However, for some applications, including long-distance buses, biomethane could play an important role in contributing to the decarbonisation of the sector, especially considering the important part of the current fleet in Italy that is already operating on fossil natural gas. This analysis presents a comparison of the potential role of biomethane to support public transport decarbonization in Italy, by estimating CO2 equivalent emissions savings considering the current biogas plants and natural gas buses in Italian cities. An additional evaluation is performed considering the future expected evolution of biomethane production in line with the new Piano Nazionale Integrato per l’Energia e il Clima, that aims to a total production of 5.7 bcm by 2030, as well as the expected 1.5 bcm of biomethane allocated to the transport sector. Within these maximum potential levels, the results of the analysis demonstrate the important savings that can be achieved with biomethane, especially when exploiting specific feedstocks that have a very low impact in terms of well-to-wheels emissions. Biomethane can represent an interesting complement to electric buses, as it can exploit the already existing fleet based on natural gas, and it also shows a number of advantages on routes that are not suitable for electric buses.

Management of Tanning Waste from Leather Processing by Anaerobic Digestion Using a Dynamic Method on a Semi-Technical Scale

In the context of climate policy, measures are being taken around the world to reduce pollution. These have been intensified in the areas of transport, industry, and energy, with the goal of zero emissions. The role of the biogas plant in energy transition and as a waste treatment plant for disposal is very important. This article describes research on a dynamic anaerobic digestion (AD) process plant. The subject of this study was leather shavings, which is a problematic waste. The research presented here is intended to demonstrate the decomposition of the flesh in the process, to confirm its biogas yield, and to evaluate the biological and technical parameters of the process. High biochemical stability was achieved for each of the tests evaluated, and no specific technical requirements were demonstrated. The only technical aspect to be addressed during operation was sedimentation, which can be solved by preparing the mixture earlier or by changing the mixing method. This made it reasonable to investigate the material further in the context of an industrial project. The characteristics of protein degradation in the AD process resulted in a high methane content in the biogas, above 65%. It was also observed that the long conditioning time of biogas in the gas cushion favourably affected the proportion of methane in biogas. Analytical results confirmed 77.5% methane content, which was a very good result. This paper presents the results of a surprising effect of chromium, primarily Cr (III), on the performance of anaerobic digestion.