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Evaluation of Changes in the Chemical Composition of Grasses as a Result of the Methane Fermentation Process and Biogas Production Efficiency
Methane fermentation, which is one of the key processes in biogas production, plays an important role in the conversion of biomass to energy. During this process, changes occur in the chemical composition of organic feedstocks, including the chemical composition of grasses. The assessment of these changes is crucial for the efficiency and productivity of biogas production. The material for this study comprised fully mature grass blades with leaves and inflorescences and was collected from extensively used meadows and pastures, as well as cultivated and set-aside areas in the Wielkopolskie Voivodeship, the communes of Białośliwie and Trzcianka, Poland. The aim of this study was to compare methane fermentation efficiency in nine grass species and identify the biomass component involved in biogas production. The results indicate that the fermentation process, as expected, changed the cellulose content. The lignin content of the grasses before fermentation varied more than the cellulose content. The content of holocellulose (sum of carbohydrate components) in the grasses ranged from 59.77 to 72.93% before fermentation. Methane fermentation significantly reduced the carbohydrate content in the grasses, with a low degree of polymerization. Grassland biomass-based biogas production is a viable alternative to conventional fossil fuels.
Lowland Sedge Meadows as a Potential Source of Macro and Micronutrient Supplementation
From the point of view of farming utilization, investigations on the recognition of the mineral composition of sedges appears important, appropriate and useful. Sedges are often found in many meadow and pasture communities. It is therefore worth paying attention to the mineral content of their tissues and their possible impact on the organisms of farm animals such as pigs. The basic objective of this study was to determine the concentration of selected macro and microelements: phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), iron (Fe), silicon (Si), copper (Cu), zinc (Zn), chrome (Cr) and nickel (Ni) in the biomass of seven sedge species, potentially used as fodder, commonly occurring in natural sites in Central Europe. The material was collected twice during one growing season in the Krześniczka (N 52°37′14′ E 14°46′06′)—lubuskie voivodeship. The first harvest was carried out at the beginning of May, during the shooting and earring phase. The collected plant material included stems and leaves. The second harvest—the end of June—was collected at a time when the seedlings were developing flowers and young fruits, and their vegetative organs were developing dynamically. In June, the collected material represented organs in all possible development phases. The collected material was dried at a temperature of 65 °C, ground, and analyzed. The obtained results showed a difference in the content of microelements between the May and June harvest dates in the dry matter of all analyzed sedge species, which differed statistically significantly only in relation to copper. The harvest date had a statistically significant impact on the change in the content of macroelements in the dry matter of all analyzed sedge species and was associated with a decrease in the content of phosphorus, magnesium and calcium, while in the case of silicon, the delay in mowing resulted in an increase in the content of this element.
Correlation between rotational molding process temperature and degradation changes of polyethylene and composites containing coffee spent grounds used as an active filler
Ruderal Habitats: A Source for Biomass and Biogas
The aim of the study was to evaluate the chemical composition and biogas potential of selected ruderal and expansive plant species: Heracleum sosnowskyi, Aegopodium podagraria, Chaerophyllum bulbosum, Acer negundo, and Urtica dioica. Plant material was collected from a 19th-century park in the village of Niegolewo (Greater Poland Voivodship) and analyzed for cellulose, lignin, hemicellulose, extractives, and ash content before and after methane fermentation. Fermentation followed DIN 38 414-S8, and chemical analyses used standardized methods (TAPPI, Seifert, and DIN). Statistical analyses included ANOVA, CVA, and hierarchical clustering. The highest biogas yield was obtained from A. podagraria, which is associated with low lignin and high hemicellulose degradation. The results confirm the potential of ruderal biomass as a diverse source for biogas production.
The Influence of Drying Sewage Sludge with the Addition of Walnut Shells on Changes in the Parameters and Chemical Composition of the Mixture
Development of Digestate for Energy Purposes Using Excess Heat from Biogas Plants
The paper presents an analysis of methods for utilizing digestate for energy purposes from two different biogas plants using different technologies. Biogas plant A used only cattle manure and corn silage as substrates, while biogas plant B used technology based on the utilization of food production waste. The analysis showed differences in the chemical, elemental, and thermogravimetric composition of both types of digestate. An analysis of the energy inputs required to produce fuel from digestate was also performed, along with energy balance calculations. The research and analysis led to the conclusion that both types of digestate are suitable for energy recovery. The possibilities of optimizing the process using excess heat from the biogas plant were also analyzed. In the case of digestate A, the combustion heat of digestate B was 17.20 MJ·kg−1, while for digestate A, it was 14.80 MJ·kg−1. The calorific value of digestate A at 8.79% moisture content was 13.40 MJ·kg−1, while for digestate B at 6.03% moisture content, it was 15.80 MJ·kg−1, respectively.