Filters
Wpływ dodatku wybranych nośników mikrobiologicznych na wytwarzanie biogazu w procesie fermentacji metanowej
Fundamentals, Operation and Global Prospects for the Development of Biogas Plants-A Review
As the global demand for renewable energy continues to rise, biogas production has emerged as a promising solution for sustainable energy generation. This review article presents the advantages of biogas technologies (mainly agricultural, based on waste of animal and plant origin) and extensively discusses the main principles of biogas production in the anaerobic digestion (AD). In this respect, the main parameters of the process, which require monitoring and decisive for its efficiency are described, therefore: temperature, pH value, retention time and organic loading rate (OLR). The principles of substrate selection are also discussed and the necessity and advantages of the use of organic waste according to the model of a circular economy and the concept of sustainable development, are indicated. It is emphasized that according to the new European regulations, the crops classified as food cannot be considered energy crops. The part on biogas production is summarised with an explanation of the necessity to treat and purify biogas. Biogas purification is important from the point of view of the efficiency of its conversion into electricity. A special place in this paper is devoted to the design, construction, functioning and operation of biogas plants, based on both scientific and practical aspects. In conclusion of this chapter, the economic aspects and profitability of operating biogas plants are discussed. Cost and benefit analyses are the major tool used for the systematic evaluation of the financial costs and potential benefits associated with the operation of biogas plants. The important fact is that the return on investment can be achieved within a few years, provided the activities are well-planned and executed. In addition to the fundamental issues of the operation of biogas plants, this article presents the global situation regarding the development of biogas plants, discussing in detail the specific needs and limitations on different continents. It is a interesting and extensive part of this article. The global agricultural biogas market is at very different levels of development. Most such installations are located in Asia and Europe. China has the highest number of biogas plants, with more than 100,000 biogas plants, followed by Germany with over 10,000 plants. In addition to the 100,000 biogas plants, China also has a large number of household biogas units, which gives a total of approx. 40 million operating units. The article concludes with a discussion of opportunities and barriers to the development of biogas plants, pointing to: financial issues, access to feedstock, political regulations, public awareness and the geopolitical situation. The most frequently cited reasons for investment failure include economic problems, lack of professional knowledge.
Ocena jakościowych i ilościowych zmian mikrobiomu bakteryjnego w procesie beztlenowego rozkładu materii organicznej
Bioenergy from Maize Silage by Anaerobic Digestion: Batch Kinetics in Relation to Biochemical Composition
Maize silage can play a key role in policies aimed at stabilising local energy systems, as it constitutes a critical renewable feedstock for European biogas plants. By providing a dense and predictable source of chemical energy, it supports balance and reliability in the agricultural energy sector. To convert this potential into stable energy production, operators require kinetic models that translate routine silage quality indicators into concrete guidance for digester operation and control. Therefore, the aim of this article was to evaluate the batch kinetics of anaerobic digestion (AD) of maize silage and to select an adequate model for describing biochemical methane potential (BMP) profiles and associated energy recovery in the context of start-up, organic loading rate (OLR), hydraulic retention time (HRT) and feedstock preparation. Ten batches of silage (A–J) were examined, covering a realistic range of pH, electrical conductivity (EC), dry and volatile solids, ash, protein–fat–fibre fractions, fibre composition (NDF, ADF and ADL), derived fractions (hemicellulose, cellulose, and residual organic matter (OM)), C/N ratio and macro-/micronutrient profiles, including trace elements relevant to methanogenesis (Ni, Co, Mo, and Se). BMP tests were carried out in batch mode, and the resulting curves were fitted using the modified Gompertz and a first-order kinetic model. Methane yields of approx. 100–120 m3 CH4/Mg fresh matter (FM) and 336–402 m3 CH4/Mg volatile solids (VS), with CH4 contents of 52–57% v/v, were typical for energy-grade maize silage. Kinetic and energetic behaviours were governed mainly by residual OM and hemicellulose (shortening the lag phase and increasing the maximum methane production rate), the ADL/cellulose ratio (controlling the slower hydrolytic tail), EC and Na/Cl/S (extending the lag phase), and C/N together with Ni/Co/Mo/Se (stabilising methanogenesis). The modified Gompertz model reproduced BMP curves with a pronounced lag phase and asymmetry more accurately (lower error and better information criterion values), and its parameters directly support start-up design, OLR ramp-up and energetic performance optimisation in bioenergy reactors. The novelty of this work lies in combining batch BMP tests, comparative kinetic modelling and detailed silage characterisation to establish quantitative links between kinetic parameters and routine maize silage quality indicators that are directly relevant for biogas plant operation and renewable energy production.
Application of Machine Learning Using Color and Texture Analysis to Recognize Microwave Vacuum Puffed Pork Snacks
The objective of the study was to create artificial neural networks (ANN) capable of highly efficient recognition of modified and unmodified puffed pork snacks for the purposes of obtaining an optimal final product. The study involved meat snacks produced from unmodified and papain modified raw pork (Psoas major) by means of microwave-vacuum puffing (MVP) under specified conditions. The snacks were then analyzed using various instruments in order to determine their basic chemical composition, color and texture. As a result of the MVP process, the moisture-to-protein ratio (MPR) was reduced to 0.11. A darker color and reduction in hardness of approx. 25% was observed in the enzymatically modified products. Multi-layer perceptron networks (MLPN) were then developed using color and texture descriptor training sets (machine learning), which is undoubtedly an innovative solution in this area.
Eco-Friendly and Effective Diatomaceous Earth/Peat (DEP) Microbial Carriers in the Anaerobic Biodegradation of Food Waste Products
This article aims to present the results of research on anaerobic digestion (AD) of waste wafers (WF-control) and co-substrate system—waste wafers and cheese (WFC-control), combined with digested sewage sludge. The aim of this study was to assess the physicochemical parameters of the diatomaceous earth/peat (DEP; 3:1) carrier material and to verify its impact on the enzymatic activity and the process performance. The experiment was conducted in a laboratory, in a periodical mode of operation of bioreactors, under mesophilic conditions. The results of analyses of morphological-dispersive, spectroscopic, adsorption, thermal, and microbiological properties confirmed that the tested carrier material can be an excellent option to implement in biotechnological processes, especially in anaerobic digestion. As part of the experiment, the substrates, feedstock, and fermenting slurry were subjected to the analysis for standard process parameters. Monitoring of the course of AD was performed by measuring the values of key parameters for the recognition of the stability of the process: pH, VFA/TA ratio (volatile fatty acids/total alkalinity), the content of NH4+, and dehydrogenase activity, as an indicator of the intensity of respiratory metabolism of microorganisms. No significant signals of destabilization of the AD process were registered. The highest dehydrogenase activity, in the course of the process, was maintained in the WFC + DEP system. The microbial carrier DEP, used for the first time in the anaerobic digestion, had a positive effect on the yield of methane production. As a result, an increase in the volume of produced biogas was obtained for samples fermented with DEP carrier material for WF + DEP by 13.18% to a cumulative methane yield of 411.04 m3 Mg−1 VS, while for WFC + DEP by 12.85% to 473.91 m3 Mg−1 VS.
Economic balance and investment profitability of the case-study agricultural biogas plant (0.499 MW) in Poland
The economic balance of agricultural biogas plants (ABPs) depends on several key factors, including feedstock availability, investment and operational costs, energy market conditions, and government support mechanisms. Despite numerous review papers and general assessments of biogas profitability, the literature for the Polish context lacks a transparent, replicable case study of an operating ABP with cost and revenue items detailed to the operational level. There is also a shortage of studies that set out, in a straightforward manner, the factors and calculations that directly determine the profitability of Polish agricultural biogas plants. As a result, analyses complemented by ROI and NPV (net present value), together with sensitivity testing of key drivers (energy prices; CAPEX – capital expenditure, OPEX – operating expenditure) in the context of post-2023 regulatory changes, remain scarce. Responding to this gap, the aim of this work is to present a simplified economic balance of a biogas plant operating in Poland, evaluating its profitability based on key operational and financial factors. The analysis confirms that the examined ABP generates profits, primarily owing to its well-developed infrastructure and efficient resource utilisation. A significant advantage of this project is the availability of on-farm agricultural residues and agri-food by-products, which considerably reduce feedstock costs and ensure consistent substrate composition. Furthermore, the plant achieves cost savings through efficient heat management and generates income from the sale of digestate. The studied ABP secures annual profits of 2,821,930.08 PLN, demonstrating that under favourable conditions, such installations can be both economically viable and environmentally sustainable.
The Problem of Weed Infestation of Agricultural Plantations vs. the Assumptions of the European Biodiversity Strategy
Meeting the nutritional needs of a dynamically developing global society is a major challenge. Despite the modernisation of agriculture, huge losses in the quality and quantity of crops occur each year, mainly due to weed species, which are the most important biotic limitation to agricultural production. Globally, approximately 1800 weed species cause a 31.5% reduction in plant production, which translates to USD 32 billion per year in economic losses. However, when the same herbicides are frequently applied, plants develop segetal immune mechanisms. There are currently around 380 herbicide-resistant weed biotypes worldwide. Due to the negative influence of herbicides on ecosystems and the legal regulations that limit the use of chemical crop protection products, it is necessary to develop a new method of weed control. Bioherbicides, based on living organisms or their secondary metabolites, seem to be an ideal solution. The biocontrol market is worth around EUR 550 million in Europe and EUR 1.6 billion worldwide, with an estimated 15% growth expected by 2025. Despite numerous studies that have demonstrated the effectiveness of microbial bioherbicides, only 25 mould-based bioherbicides are currently available to growers. Due to the high specificity and selectivity of biological crop protection products, as well as their low production costs and non-toxicity to the environment and human health, they would appear to be a safe alternative to chemical pesticides.
Quantitative and Qualitative Changes in the Genetic Diversity of Bacterial Communities in Anaerobic Bioreactors with the Diatomaceous Earth/Peat Cell Carrier
This paper analyses the impact of the diatomaceous earth/peat (DEP; 3:1) microbial carrier on changes in the bacterial microbiome and the development of biofilm in the anaerobic digestion (AD) of confectionery waste, combined with digested sewage sludge as inoculum. The physicochemical properties of the carrier material are presented, with particular focus on its morphological and dispersion characteristics, as well as adsorption and thermal properties. In this respect, the DEP system was found to be a suitable carrier for both mesophilic and thermophilic AD. The evaluation of quantitative and qualitative changes in the genetic diversity of bacterial communities, carried out using next-generation sequencing (NGS), showed that the material has a modifying effect on the bacterial microbiome. While Actinobacteria was the most abundant cluster in the WF-control sample (WF—waste wafers), Firmicutes was the dominant cluster in the digested samples without the carrier (WF-dig.; dig.—digested) and with the carrier (WF + DEP). The same was true for the count of Proteobacteria, which decreased twofold during biodegradation in favor of Synergistetes. The Syntrophomonas cluster was identified as the most abundant genus in the two samples, particularly in WF + DEP. This information was supplemented by observations of morphological features of microorganisms carried out using fluorescence microscopy. The biodegradation process itself had a significant impact on changes in the microbiome of samples taken from anaerobic bioreactors, reducing its biodiversity. As demonstrated by the results of this innovative method, namely the BioFlux microfluidic flow system, the decrease in the number of taxa in the digested samples and the addition of DEP contributed to the microbial adhesion in the microfluidic system and the formation of a stable biofilm.
Wpływ solanki z regeneracji zmiękczania wody na działanie przydomowej oczyszczalni ścieków oraz przewodność hydrauliczną gruntu
Nośniki w fermentacji metanowej bioodpadów: ujęcie procesowo–mikrobiologiczne na przykładzie wybranych układów
Agricultural Biogas Plant as a Thermodynamic System: A Study of Efficiency in the Transformation from Primary to Secondary Energy
Using a wide range of organic substrates in the methane fermentation process enables efficient biogas production. Nonetheless, in many cases, the efficiency of electricity generation in biogas plant cogeneration systems is much lower than expected, close to the calorific value of the applied feedstock. This paper analyses energy conversion efficiency in a 1 MWel agricultural biogas plant fed with corn silage or vegetable waste and pig slurry as a feedstock dilution agent, depending on the season and availability. Biomass conversion studies were carried out for 12 months, during which substrate samples were taken once a month. The total primary energy in substrates was estimated in laboratory conditions by measuring the heat of combustion in a ballistic bomb calorimeter (17,760 MWh·year-1), and in the case of pig slurry, biochemical methane potential (BMP, (201.88±3.21 m3·Mg VS-1). Further, the substrates were analysed in terms of their chemical composition — from protein, sugar and fat content to mineral matter determination, among other things. The results obtained during the study were averaged. Based on such things as the amount of biogas produced at the plant, the amount of chemical (secondary) energy contained in methane as a product of biomass conversion (10,633 MWh·year-1) was calculated. Considering the results obtained from the analyses, as well as the calculated values of the relevant parameters, biomass conversion efficiency was determined as a ratio of chemical energy in methane to (primary) energy in substrates, which was 59.87%, as well as electricity production efficiency, as a ratio of electricity produced (4,913 MWh·year-1) to primary energy, with a 35% cogeneration system efficiency. Full energy conversion efficiency, related to electricity production, reached a low value of 27.66%. This article provides an insightful, unique analysis of energy conversion in an active biogas plant as an open thermodynamic system.
Kinetics and Energy Yield in Anaerobic Digestion: Effects of Substrate Composition and Fundamental Operating Conditions
End-of-Life Strategies for Wind Turbines: Blade Recycling, Second-Life Applications, and Circular Economy Integration
Wind power is integral to the transformation of energy systems towards sustainability. However, the increasing number of wind turbines approaching the end of their service life presents significant challenges in terms of waste management and environmental sustainability. Rotor blades, typically composed of thermoset polymer composites reinforced with glass or carbon fibres, are particularly problematic due to their low recyclability and complex material structure. The aim of this article is to provide a system-level review of current end-of-life strategies for wind turbine components, with particular emphasis on blade recycling and decision-oriented comparison, and its integration into circular economy frameworks. The paper explores three main pathways: operational life extension through predictive maintenance and design optimisation; upcycling and second-life applications; and advanced recycling techniques, including mechanical, thermal, and chemical methods, and reports qualitative/quantitative indicators together with an indicative Technology Readiness Level (TRL). Recent innovations, such as solvolysis, microwave-assisted pyrolysis, and supercritical fluid treatment, offer promising recovery rates but face technological and economic as well as environmental compliance limitations. In parallel, the review considers deployment maturity and economics, including an indicative mapping of cost and deployment status to support decision-making. Simultaneously, reuse applications in the construction and infrastructure sectors—such as concrete additives or repurposed structural elements—demonstrate viable low-energy alternatives to full material recovery, although regulatory barriers remain. The study also highlights the importance of systemic approaches, including Extended Producer Responsibility (EPR), Digital Product Passports and EU-aligned policy/finance instruments, and cross-sectoral collaboration. These instruments are essential for enhancing material traceability and fostering industrial symbiosis. In conclusion, there is no universal solution for wind turbine blade recycling. Effective integration of circular principles will require tailored strategies, interdisciplinary research, and bankable policy support. Addressing these challenges is crucial for minimising the environmental footprint of the wind energy sector.
