The aim of this study was to determine selected energy parameters, leachability of heavy metals and phytotoxicity of biomass ash for different types of plant biomass (wheat straw, miscanthus straw, bark and sawdust) and poultry manure, as well as biochars produced from them. Based on data from proximate and ultimate analysis of the investigated materials, fuel value index (FVI) was calculated to determine their suitability for energy production. The ashes were analyzed for both chemical composition and leaching behavior. The phytotoxicity test of aqueous ash extracts was performed for Lepidium sativum L. It was found that the calorific value of biochars was higher on average by 36% than the value determined for feedstocks used in the pyrolysis process. The pyrolysis of organic materials resulted in the reduction of the volatile matter content. The gross calorific value was determined in biochars formed from miscanthus straw and sawdust which were 26.6 and 23.4 MJ kg −1 , respectively. Leachability of heavy metals of biomass ash was highly diverse and depended on the analyzed element and the material type. The phytotoxicity analysis showed that, in general, each of the ash extracts tested had a positive effect on the growth of Lepidium sativum L. compared to the control. The use of ash, fertilizer, or sorbents can be an interesting alternative for materials with high ash content. In all these cases, biochars seem to be very attractive materials that can be used not only in energy production. Given the high carbon content of biochar obtained in the pyrolysis process, it has a high-energy potential and can be used as a biofuel.

The article discusses an innovative system used for aerobic biostabilisation and biological drying of solid municipal waste. A mechanical–biological process (MBT) of municipal solid waste (MSW) treatment were carried out and monitored in 5 bioreactors. A two-stage biological treatment process has been used in the investigation. In the first step an undersize fraction was subjected to the biological stabilisation for a period of 14 days as a result of which there was a decrease of loss on ignition, but not sufficient to fulfill the requirements of MBT technology. In the second stage of a biological treatment has been applied 7-days intensive bio-drying of MSW using sustained high temperatures in bioreactor. The article presents the results of the chemical composition analysis of the undersize fraction and waste after biological drying, and also the results of temperature changes, pH ratio, loss on ignition, moisture content, combustible and volatile matter content, heat of combustion and calorific value of wastes. The mass balance of the MBT of MSW with using the innovative aeration system showed that only 14.5% of waste need to be landfilled, 61.5% could be used for thermal treatment, and nearly 19% being lost in the process as CO2 and H2O.

Soil microorganisms play a key role in many biochemical processes essential for the environment and for the ecological and production functions of soils, hence they are very important quality indicators. The study aimed at evaluating the effect of 1 and 2% additions of wheat and miscanthus straw biochars on soil enzymatic activity (dehydrogenases, urease, phosphatases) and the number of microorganisms (bacteria, fungi, actinobacteria). Pot experiments were carried out on soil with a loamy sand texture. The geometric mean of enzyme activities, biological index of fertility, and the integrated total enzyme activity index were used to explore the relationships between soil enzyme activities and the microbiological and chemical properties of soil. The addition of 1% miscanthus straw biochar had the most beneficial effect on the number of bacteria and fungi (increase by 380 and 26%, respectively), and 1% wheat straw biochar on the number of actinomycetes (increase by 273%). The correlation analysis between the number of actinomycetes and the chemical parameters of the soil showed the significant effect of the content of N total (r = 0.76) and C total (r = 0.85). The values of biological index of fertility, total enzyme activity index and geometric mean of enzyme activities indexes showed that the best quality of soil was produced by a 2% addition of wheat straw biochar.

Increasing production of waste has compelled the development of modern technologies for waste management. Certain fractions of municipal solid wastes are not suitable for recycling and must be utilised in other ways. Materials such as refuse-derived fuel (RDF) fractions are used as fuel in cement or CHP (combined heat and power) plants. The low bulk density leads to many problems pertaining to transportation and storage. In the case of biomass, these problems cause reduction in pelletisation. This paper therefore presents a comprehensive study on RDF pellet production, which is divided into three major areas. The first describes laboratory-scale tests and provides information on key factors that affect pellet quality (e.g., density and durability). Based on this, the second part presents a design of modified RDF dies to form RDF pellets, which are then tested via a semi-professional line test. The results show that RDF fraction can be compacted to form pellets using conventional devices. Given that temperature plays a key role, a special die must be used, and this ensures that the produced pellets exhibit high durability and bulk density, similar to biomass pellets.

Abstract. In Poland, biomass is still considered as the basic source of renewable energy. Energy from biomass accounts for 15 % of global energy consumption, while in developing countries this share is higher. The main advantage of biomass is lower emissions of sulphur dioxide during combustion compared to fossil fuels. The main sources of biomass for production of low-processed solid biofuels, such as bales or chips and high processed pellets or briquettes, are plantations of energy plants. Energy plant species, possible to use as a raw material for the production of biofuels, are plants characterized by a high annual growth, resistance to diseases and pests, small habitat requirements and adaptation to the Polish climatic conditions. The paper presents the physico-chemical properties of coconut shells in terms of their energetic use. The results obtained are: humidity (9.4 %), calorific value (17308.68 J·g -1 ), low ash content (0.66 %) and volatile content (77.7 %) are comparable to those of biofuels available on the market. The work was also carried out to assess the effect of the shredding degree and the applied agglomeration pressure in the briquetting process on the quality characteristics of the obtained briquettes. For briquetting the raw materials the POR ECOMEC Junior Press was used. Tests were conducted for particulate matter on 8 and 12 mm sieves and for agglomerate pressure of 37 and 47 MPa. The obtained results showed that proper granulation of the raw material and application of appropriate agglomeration pressure improve the qualities of the briquettes.