Biogas Plants Research Articles

From Field to Model: Determining EROSION 3D Model Parameters for the Emerging Biomass Plant Silphium perfoliatum L. to Predict Effects on Water Erosion Processes

The agricultural production of maize (Zea mays L.) increases the risk of water erosion. Perennial crops like cup plant (Silphium perfoliatum L.) offer a sustainable alternative to produce biomass for biogas plants. The assessment of soil conservation measures requires calibrated soil erosion models that spatially identify soil erosion processes. These support decision-making by farmers and policymakers. Input parameters for the physically based soil erosion model EROSION 3D for cup plant cultivation were established in a field study. Rainfall simulation experiments were conducted to determine the model input parameter’s skinfactor and surface roughness. The results showed a reduction of soil erosion and higher infiltration rates for cup plant resulting in higher skinfactors of 11.5 in June and 0.75 post-harvest (cup plant) compared to 1.2 in June and 0.21 post-harvest (maize). With the extended parameter catalogue of EROSION 3D for cup plant cultivation model simulations were conducted for a rainfall event in June (64 mm). The sediment budget would have been reduced by 92.6% through the growth of cup plant in comparison to conventionally grown maize. Perennial cup plant can, therefore, contribute to achieving the targets outlined in the European Green Deal by reducing soil erosion and enhancing soil health.

State estimation of a biogas plant based on spectral analysis using a combination of machine learning and metaheuristic algorithms

The continuous monitoring of the state variables of a biogas plant remains a challenge due to the necessity of an appropriate measuring device. The collection, transportation, and laboratory measurement of the biogas sample are required, and regularly performing these activities is expensive and time-consuming. The objective of this study is to investigate a potential solution for the real-time monitoring of the state variables of a biogas plant, which involves the integration of spectral data from near-infrared (NIR) sensors with advanced machine learning (ML) and metaheuristic algorithms. A total of 635 samples were prepared in a laboratory and subsequently analyzed using portable NIR sensors mounted in sensor brackets that were 3D-printed for this study. The resulting spectral data were subjected to several preprocessing processes, and this study combines numerous methods rather than selecting the optimal one. Several ML models were then trained on the processed data, which have a realistic range as in the actual biogas plant. The developed algorithm exhibits an accuracy level greater than 82 % when classifying the volatile fatty acids (VFA)/total alkalinity (TA) ratio and acetic acid concentration of biogas samples. Furthermore, the dry matter content of biogas samples can be accurately predicted with an RMSE of approximately 1.6 %. In addition, the significance of selecting suitable hyperparameters is demonstrated, which may substantially influence the outcome. These findings indicate that NIR sensors are a realistic option for monitoring the operational status of biogas plants.

Limosilactobacillus Regulating Microbial Communities to Overcome the Hydrolysis Bottleneck with Efficient One-Step Co-Production of H2 and CH4.

The efficient co-production of H2 and CH4 via anaerobic digestion (AD) requires separate stages, as it cannot yet be achieved in one step. Lactic acid bacteria (LAB) (Limosilactobacillus) release H2 and acetate by enhancing hydrolysis, potentially increasing CH4 production with simultaneous H2 accumulation. This study investigated the enhanced effect of one-step co-production of H2 and CH4 in AD by LAB and elucidated its enhancement mechanisms. The results showed that 236.3 times increase in H2 production and 7.1 times increase in CH4 production are achieved, resulting in profits of 469.39 USD. Model substrates lignocellulosic straw, sodium acetate, and H2 confirmes LAB work on the hydrolysis stage and subsequent sustainable volatile fatty acid production during the first 6 days of AD. In this stage, the enrichment of Limosilactobacillus carrying bglB and xynB, the glycolysis pathway, and the high activity of protease, acetate kinase, and [FeFe] hydrogenase, jointly achieved rapid acetate and H2 accumulation, driving hydrogenotrophic methanogenesis dominated. From day 7 to 24, with enriched Methanosarcina, and increased methenyltetrahydromethanopterin hydrogenase activity, continuously produced acetate led to the mainly acetoclastic methanogenesis shift from hydrogenotrophic methanogenesis. The power generation capacity of LAB-enhanced AD is 333.33 times that of China's 24,000m3 biogas plant.

Estimating Sludge Deposition on the Heat Exchanger in the Digester of a Biogas Plant

Estimating Sludge Deposition on the Heat Exchanger in the Digester of a Biogas Plant

Optimization framework of clean heat and CO2 supply for agricultural greenhouses exploiting industrial symbiosis

The rising demand for greenhouse cultivation poses a challenge in providing environmentally friendly energy to maintain favorable greenhouse indoor conditions. This research presents an optimization model to identify cost-optimal symbiotic pathways to replace the import of three key greenhouse crops (tomato, cucumber, lettuce) with local greenhouse production. The proposed solutions involve greenhouses that can meet these crops' heat and CO2 demands via industrial symbiosis. Switzerland is investigated as the case study, and the (waste) heat suppliers are municipal solid waste incinerators, cement production plants and biogas plants. Upgrading biomethane production plants are also considered potential CO2 suppliers. The objective is to minimize the discounted cost when replacing 25%–100 % of vegetable imports with local agricultural greenhouses, considering availability of suitable land as well as waste heat and CO2 suppliers. Optimization results suggest prioritizing northeast and west Switzerland for greenhouse development, due to the availability of suitable land and proximity of waste heat and CO2 suppliers. Waste incinerators could provide 50%–70 % of the necessary heat, while Organic Rankine cycle in cement plants could generate 63 % of the electricity of supplementary lighting demand of greenhouses. While tailored for Switzerland, the optimization framework's general formulation can be adapted also to other regions to optimize greenhouses' heat and CO2 demands. The optimization code is provided open source for associated applications.

Toward low‐carbon cities: A review of circular economy integration in urban waste management and its impact on carbon emissions

AbstractUrban areas significantly contribute to global carbon emissions, necessitating a shift toward low‐carbon environments. The concept of low‐carbon cities presents a viable pathway for mitigating these anthropogenic emissions, particularly through solid waste management. This article explores the critical role of circular economy‐integrated waste management (CEWM) strategies in reducing carbon emissions and fostering sustainable urban development. We examine city‐level CEWM initiatives worldwide, assess the carbon emission quantification methods, and highlight specific CEWM strategies with significant carbon reduction potential. Our findings reveal that city‐level initiatives predominantly prioritize waste reduction and prevention (51%), followed by education and engagement (23%), material recycling and upcycling (21%), and waste conversion (6%). Key strategies such as composting, waste sorting, recycling, and biogas plants have demonstrated substantial potential in reducing carbon emissions. Integrating CE principles with waste management transforms the traditional linear take‐make‐dispose model into a circular approach that minimizes waste and maximizes resource efficiency. This integration is crucial for reducing carbon emissions and promoting a sustainable urban environment. A holistic perspective is required to plan and strategize for sustainable urbanization whereby CE and waste management are interconnected. CE principles provide an ideal foundation that enhances waste management strategies toward sustainability, ultimately leading to reduced carbon emissions. This article provides essential insights to equip decision‐makers with evidence‐based strategies for effective urban waste management.This article is categorized under: Climate and Environment > Circular Economy Sustainable Development > Goals

Adaptive-DMPC based energy management and pre-installation techno-economic analysis of a grid-tied cyber-physical community microgrid

The trends for creating smart cities is increasing as it gives assurance of high-quality living standards, however, converting an existing city into a smart one needs more time, investments and is highly tedious. Another concept of community based sustainable living that can be installed in and around outskirts of any city. All the features of smart cities can be brought in by most economical, sustainable, and environmental friendly way. A cyber-physical Community Microgrid (CMG) can have various loads such as heating, cooling, security and lighting purposes. The dependency on grid supply can be reduced by using renewable sources of electricity. Solar water heaters and biogas plant can take care of heating loads. Handling uncertainties in generation, time-varying load scenarios, and dynamics of supply grid are crucial for smooth operation of cyber-physical CMG. In this work, an Energy Management Strategy (EMS) for CMG is proposed using an adaptive Distributed Model Predictive Control (DMPC) that improves scalability with modular architecture, allow enhanced flexibility and adaptability, robustness and reliability, enhanced optimization and predictive capabilities. All possible intermittencies types due to renewables, time-variable demand profiles, smooth charging/discharging cycles and longevity of storage batteries, curtailing of noncritical loads, and dynamic price of grid consumption are applied. Further, use of EMS outcomes is done to develop pre-installation techno-economic analysis for establishing a CMG with optimal component sizing. The given DMPC scheme for CMG is verified by conducting comprehensive test case studies over 24 hrs interval on the Matlab/Simulink and hardware-in-loop testing.

Bulk scale synthesis of high-performance carbon nanomaterial from biogas plant residual waste: Tuned porosity and composition for advanced supercapacitor applications

Carbon based nanomaterials with tuned porosity and compositions are of great interest in terms of energy storing materials. Nevertheless, it is still a challenge to produce such nanostructures on a large scale in cost-effective manner. In this work, we demonstrate that carbon nanomaterial (CNM) can be prepared using biogas plant residual waste (BPRW) as the precursor on a bulk scale under the specific two step pyrolysis technique. The optimized process along with the catalyst used is crucial as the simple pyrolysis of precursor can only produce traditional activated carbon with significantly lower specific capacitance values. The spherical structure of silica nanoclusters and graphitic skeleton of synthesized CNM confirmed with the help of FE-SEM, AFM and HR-TEM along with Raman and XRD while EDX, XPS, and FT-IR studies confirm the presence of various functional groups along with their respective percentage composition. These CNMs show mesoporous structure of the nanomaterial. Among three different aqueous electrolytes, the maximum specific capacitance of 371.88 Fg−1 at 0.5 Ag−1 current density in 1 M H2SO4 indicates its suitability for the practical supercapacitor applications. The fabricated symmetric supercapacitor device using CNMs as the electrode material and 1 M H2SO4 as the electrolyte shows very good specific capacitance value with the high energy density of 34.4 Whkg−1 corresponding to 360 Wkg−1 power density along with the good cyclic stability over 10,000 cycles of charge–discharge. This innovative technique paves the way towards upcycling any lignin containing waste material into carbon-based nanomaterial on a bulk scale by an effective method, which can be further used as high-performance electrode material for energy storage applications like in supercapacitors and batteries.

Improving biogas production with application of trimetallic nanoparticle using response surface methods

The potential of trimetallic nanoparticles (TMNPs) to enhance biogas production through microbe-to-microbe interactions and boost biogas yield is evident. This present study employed the central composite design (CCD) of response surface methods (RSM) to determine the optimal conditions of iron-cobalt-zinc TMNPs influenced anaerobic digestion for higher biogas yield. The impact of initial pH (6.6–7.4), TMNPs concentration (0–30 mg L−1), temperature (25-45 °C), and hydraulic retention time (HRT) (0-4 days) were modelled for improved biogas production. The results indicated that the linear model terms of pH and TMNPs concentration, and quadratic model terms of temperature and HRT, significantly affect the biogas production. Linear model terms of TMNPs, temperature, pH, and HRT have significant interactive effects and the numerical analysis identified the best conditions for the evaluated parameters. Ideal anaerobic process settings generated a maximum cumulative biogas production of 3700 mL−1POME than blank (2000 mL−1), corresponding to an 85 % yield. Optimizing the initial pH, TMNPs concentration, temperature, and HRT can significantly improve biogas yield and could be helpful for developing more efficient AD processes at large volume and commercial biogas plants. Promoting TMNPs as catalysts positively improves an AD process towards sustainable biogas production.

Process stability in anaerobic Digestion: Unveiling microbial signatures of full-scale reactor performance

Anaerobic digestion is responding to the growing demand for sustainability by exploring alternatives for methane production through renewable processes. The target is to implement stable production systems at industrial scale that can accommodate heterogeneous feedstocks with seasonal or intermittent availability. In this study, we investigated the microbiomes of six full-scale biogas plant digesters, operated under continuous production with distinct feedstock and varying operating parameters, by monitoring multiple time points over an 18-month period. This time-course experiment analyzed 114 Metagenome-Assembled Genomes alongside physico-chemical assessments to identify common and plant-specific indicators for operational management. Results identify a Limnochordia and a Dysgonomonadaceae bacteria, as well as Candidatus Methanoculleus thermohydrogenotrophicum, as widespread and potentially desirable components of the microbiota for resilient digestion of varying waste, including the peculiar olive pomace. The abundance of individual taxonomic groups and their reconstructed metabolic pathways aligned with the availability of their fermentation substrates, finding a prevalence of beta-oxidizing bacteria with lipid-rich olive pomace. Monitoring through perturbation events revealed possible causative and remediative microbiological factors, in particular Methanosarcina flavescens and Candidatus Syntrophosphaera thermopropionivorans could contribute to restoration of reactor performance. This work showcases relationships between digester operation and its microbiome, supporting microbial monitoring as a tool to increase biogas production efficiency.

Modeling and manufacturing of solar modules of different designs for energy supply of biogas plant

The article presents a description of the modeling and manufacturing of solar modules of photovoltaic, thermal and photovoltaic thermal designs intended to supply energy to a biogas plant intended for the production of biohydrogen and biomethane. Mathematical modeling of the photovoltaic module was carried out and the calculated temperature of the photovoltaic converters was determined, and also the photovoltaic module was manufactured using the process of sealing the photovoltaic converters with a two-component polysiloxane compound. Mathematical modeling of a solar thermal collector with water radiators in the form of a round copper tube, an oval copper tube, as well as a rectangular water cooling channel (“water jacket”) was also carried out, in which pressure losses and the amount of water heating were assessed. The distances between the rectangular channels of the water-cooling radiator for uniform heat removal were determined, and mathematical modeling of the thermal state of a solar thermal collector with a semicircular cross-section of the water-cooling radiator channel was carried out, after which the solar thermal collector was manufactured. Mathematical modeling of the total displacements of the components of a photovoltaic thermal module, the values of which do not exceed acceptable limits, was carried out, after which a photovoltaic thermal module was manufactured using the process of sealing photovoltaic converters with a two-component polysiloxane compound.

Analysis of an anaerobically digested animal waste-based microturbine driven-biogas energy system

The paper designs a biogas power plant that runs on anaerobically digested (AD) animal waste and integrated with a micro turbine and permanent magnet synchronous generator to generate renewable power. Cow dung, poultry manure, and swine have been explored as potential feedstocks for AD, and the various subprocesses are investigated at discrete temperature intervals that cover both the mesophilic and thermophilic temperature ranges (30 °C–50 °C). The biodegradability of animal wastes, retention time, loading rate, and the size of the reactor influence the overall biogas yield. Methane production from cow dung increased from 131.4 L/d at 30 °C to 171.12 L/d at 50 °C in 15 days. Whereas the methane output from poultry manure, and swine at 50 °C were 278.4 L/d and 284.5 L/d respectively. Moreover, a methane recovery efficiency of 75 % and a purge efficiency of 97 % were attained through pressure swing adsorption (PSA). Furthermore, the system is maintained at 25 kW at steady-state conditions, attaining saturation for a torque value of 7.77 p.u. In a dynamic setting, the load is varied for a range of 25 kW–40 kW, and stable sinusoidal waveforms are generated as outputs that indicate the system's ability to withstand load variations.

Contaminants, biochemical methane potential, and biodegradability of different bio-waste categories: guidance for anaerobic digestion

This study evaluated the anaerobic digestion suitability of bio-waste from different sources by comparing their biochemical methane potential (BMP), biodegradability (BI), and content of contaminants (heavy metals and physical impurities) − an often-overlooked factor but one of particular concern in bio-waste. Predominant heavy metals included Cu and Zn, while recurring physical impurities comprised plastics and organic non-biodegradable matter. Food waste from food processing plants were most suitable, exhibiting low contamination and high biogas conversion (BMP > 549 NmLCH4/gVS and BI > 86 %). Conversely, organic fractions from mechanical biological treatment were highly contaminated, while green waste displayed low biogas conversion (BMP < 368 NmLCH4/gVS and BI < 72 %). Food waste from households and medium/large-sized producers also demonstrated high biogas conversion, but variable contamination levels could compromise their suitability. Assessing contaminants alongside BMP and BI provides a comprehensive approach for selecting suitable bio-waste feedstocks that can be introduced in biogas plants.

The sensitivity of agricultural biogas plants to changes in energy prices in Poland

In Poland, despite ambitious plans from 15 years ago, when it was assumed that by 2020, an agricultural biogas plant would be standard in every commune, the potential of agricultural biogas has not been used due to the lack of stable legal regulations and financing programmes for the construction of the plants. The situation has now changed due to new forms of support systems, which motivated the authors to compare two agricultural biogas plants operating in the certificate system and the support system in the form of feed-in premiums. Moreover, the authors pointed to differences in the number of agricultural biogas plants and their capacity by voivodeship due to changes in legal conditions in force in two periods: from 1 January 2011, to 30 June 2016, and from 1 July 2016, to 19 January 2024. Based on the research methods used ‒ including Earnings Before Interest, Taxes Depreciation and Amortisation, the Internal Rate of Return, risk matrix and data analysis in spatial terms ‒ it was indicated that: 1. agricultural biogas plants are characterised by very high sensitivity related to the probability of risk in the case of investment costs, substrate prices and changes in energy prices; 2. financial support is important at the stage of construction of a biogas plant, which largely makes it possible to shorten the payback period and thus increase the willingness of future investors to invest in biogas plants and 3. in the periods analysed, significant differences were noted in the spatial location of biogas plants due to trends towards lower-power biogas plants, which is probably dictated by the constant and predictable premium system in the new support system.

A modular framework to assess biological resource utilization impacts (BIORIM)

The strong influence of biological processes and site conditions, the large diversity in management, compositional changes of agricultural produce, and the circularity of processes challenge the assessment of environmental impacts of the bioeconomy. This paper introduces a novel sustainability assessment and material flow model to study biological resource utilization impacts (BIORIM) which aims to address these challenges. The model represents important bioeconomic production systems (e.g. arable land, dairy farm, biogas plant) and considers input properties, production parameters such as site conditions or management, and different emission factors when calculating products and emissions. For this reason, the functions that represent the conversion processes need to be executed in the correct order when analysing larger production networks. The model keeps full track of mass, carbon and nitrogen flows, and therefore allows assessing how much is lost during processing, ending up in the produce and is recycled. The modelling approach is illustrated at the example of a dairy farm where dairy manure is used as an organic fertilizer for fodder crop production in the following year. This is compared to a scenario that includes a biogas plant. The comparison of manure storage to biogas production reveals that this change does not only affects direct emissions. Biogas production leads to higher carbon losses and thus negatively affects the humus balance. The manure storage, on the other hand, leads to higher nitrogen losses, which result in a lower fertilization value of the manure, and therefore a higher amount of mineral fertilizer is required in the following year. Together with the emission savings from the energy production, this results in a lower global warming effect of the biogas scenario. The study shows that it is important to consider the interplay of processes when assessing impacts of bioeconomic production systems.

Anaerobic co-digestion of cow manure and microalgae to increase biogas production: A sustainable bioenergy source

The biogas production from microalgae has gained attention due to fast depleting of fossil fuels and oil reserves. This study evaluated the anaerobic co-digestion of microalgae in various concentrations with cow manure to enhance biogas production. The biogas production of each experiment was measured using the water displacement method. The results indicated that the addition of microalgae significantly enhanced biogas production. Particularly, high methane yield of Anabaena sp. 50 %, Chlorella sp. 50 %, control was 345 ± 2.88 mL CH4/g VS, 297.96 ± 0.49 mL CH4/g VS, 138.32 ± 0.50 CH4/g VS respectively. The slurry produced by 50 % Anabaena sp. biogas plant exhibited the greatest level of seed germination. The current study demonstrated that Sorgham bicolor had the highest seed germination rate (94.2 %) root and shoot length of all crops. Therefore, it is possible to employ Anabaena sp. (50 %) and Chlorella sp. (50 %) in the rapid production of biogas. Moreover, agricultural output would be increased by using biogas slurry.

Effect of long-term storage of cattle manure on its energy potential and biodegradability

Abstract In recent years in Russia, due to the complicated geopolitical situation in some border areas, biogas plants have been considered not only as waste utilization facilities, but also as reserve energy sources, which are safer than traditional - nuclear power plants. In this context, the development of an algorithm for the flexible operation of a biogas plant is particularly relevant, which gives rise to the need to study the stability of the system under the influence of different unfavourable factors. In this work, the influence of long-term storage of cattle manure on its energy potential and biodegradability is studied. The specific methane yield in the test variant with manure stored for 10 months before anaerobic fermentation was 1.41±0.55 ml/g oDM, which is 6.23 times lower than in the test variant with fresh manure; the methane content of manure after long-term storage is 9.66 times lower and the degree of decomposition of its organic matter is 2.72 times lower compared to similar indicators of manure processed without preliminary storage. However, the specific biogas yield from long-term stored manure is 1.66 times higher than the control, which indicates intensive formation of other gases. Thus, long-term storage has a negative impact on the energy potential of cattle manure; if it is necessary to process it in a biogas plant, it is advisable to combine it with more energy-intensive raw materials.

Biochemical Conversion of Food Waste for Energy and Agricultural Applications: Towards Sustainable Restaurant Operation in Nigeria

One of the major problems faced by many restaurants in Nigeria is high operational cost resulting from high cost of energy, food ingredients and waste disposal. Indiscriminate disposal of food wastes contribute to environmental problems such as global warming and the spread of diseases. This paper presents the design and fabrication of a biogas plant for the conversion of biodegradable food wastes into biogas and agri-supplements which can be used for domestic and commercial purposes such as cooking/heating and agricultural applications respectively. This study is geared towards the domestication of an existing technology that has not been taken seriously in Nigeria. the anaerobic digester consists mainly of the slurry inlet, the digester, gas holder and effluent discharge pipe. The slurry, a mixture of food waste and water was fed in to the digester and allowed to digest anaerobically to generate biogas consisting mainly of methane. The digestate, a harmless solid/liquid mixturewas applied as organic manure to a small portion of land in an agricultural experiment.Results of combustion tests in a locally fabricated torch presented a long, blue and quite flame, similar to that of LPG. Digested fed crops grew faster and yielded better. This projecthas the potential to enhance the operational sustainability of restaurants by lowering the cost of cooking and heating, while also supplementing vegetable supply.

The Economic Efficiencies of Investment in Biogas Plants—A Case Study of a Biogas Plant Using Waste from a Dairy Farm in Poland

High investments and low economic efficiency of agricultural biogas plants operating on farms are two of the main barriers to the development of the biogas plant sector. Identification of economic and financial problems related to the operation of such facilities allows for the reduction of entry barriers for private investors, especially farmers. The aim of this research was to analyze the economic efficiency of investing in an agricultural biogas plant operating at a dairy farm. For the analysis, the case study method was applied. The economic efficiency of investment in a biogas plant was assessed using six different cash flow options. The NPV (net present value) and IRR (internal rate of return) methods were applied to assess the economic efficiency of the investment. It was found that the investment project for an agricultural biogas plant with a capacity of 0.499 MW located at a dairy farm required a subsidy of approximately 40–60% of the value of to ensure satisfactory economic efficiency. It has been shown that a particularly important aspect in assessing the economic efficiency of an investment in an agricultural biogas plant is the use of an economic calculation that takes into account the valuation and quantification of all positive external effects of such projects.

Optimization Study on the Comprehensive Benefits of Straw Biogas Power Plants Participating in Electricity-Carbon Coupled Trading Based on Dual-Carbon Background

Optimization Study on the Comprehensive Benefits of Straw Biogas Power Plants Participating in Electricity-Carbon Coupled Trading Based on Dual-Carbon Background