The article discusses issues related to the generation, use, and transboundary movement of waste labeled with the code 191210 according to the waste catalogue regardless of its origin (municipal, industrial or mixed). Data contained in voivodship reports related to waste management and information about transboundary shipments shared by the Chief Inspectorate of Environmental Protection were also used in the article. The imbalance in the amount of produced and energetically used alternative fuels in Poland in the years 2015 to 2017 has been confirmed. This affects the economy of the waste management sector involved in the production of alternative fuels. The oversupply causes the prices of alternative fuels to fall and increases the need for subsidies in the case of the recovery or disposal of alternative fuels of lower quality. In the near future one should expect a stabilization of the supply of combustible waste to the cement industry, which is now beginning to achieve its technological potential; this is due to a high degree of replacement of fossil fuels. One should also expect an increase in the demand for alternative fuels from the commercial power sector and heating sector. It has been shown that much more alternative fuel is imported than exported from Poland. The amount of imported alternative fuel in the market is relatively low compared to the amount of fuel produced in the country. This oversupply affects, although not significantly, the possibility of using domestic waste for energy recovery. The export of the alternative fuel produced in the country is a favorable phenomenon when there is no possibility of sale on the domestic market. It seems rational, especially in the case of exports from installations producing fuels in border provinces.

The paper describes practical results of four-year laboratory studies completed to estimate technically feasible conditions of upgrading an existing sludge disposal system. A minimization of sludge mass and volume together with an energy recovery improvement were main goals of these activities. The way from lab studies and simulations to full scale investments has been shown with a special emphasis on application of respirometric procedure being applied by authors. Proposed was authors’ procedure for an estimation of a digestion time prediction for sludge of specific composition. Investigations completed at existing wastewater treatment plant resulted in practical implementation to be used during the design of upgrading and extension of the digestion and energy recovery system at the plant. It was proved that proposed changes provide close to optimum conditions for process performance and the application of proposed calculation procedures was adopted by design team

Chemical heat pumps (CHP) use reversible exothermal and endothermal chemical reactions to increase the temperature of working fluids. In comparison to the “classical” vapour compression chemical heat pumps, CHP enables us to achieve significantly higher temperatures of a heated medium which is crucial for the potential application, e.g. for production of superheated steam. Despite the advantages presented, currently, there are no installations using CHP for lowgrade waste heat recovery available on the market. The scaling up of industrial processes is still one of the greatest challenges of process engineering. The aim of the theoretical and experimental concept study presented here was to evaluate a method of reclaiming energy from low temperature waste streams and converting it into a saturated steam of temperature from 120 to 150 ◦C, which can be useful in industry. A chemical heat pump concept, based on the dilution and concentration of phosphoric acid, was used to test the method in the laboratory scale. The heat of dilution and energy needed for water evaporation from the acid solutionwere experimentally measured. The cycle of successive processes of dilution and concentration has been experimentally confirmed. A theoretical model of the chemical heat pump was tested and coefficient of performance measured.

The research was intended to develop a biocomposite as an alternative biodegradable material, for the production of, e.g., disposable utensils. The author’s tested thermoplastic maize starch, both without additives and with the addition of crumbled fl ax fi ber in the share of 10, 20 and 30 wt%. The plasticizer added was technical glycerin and the samples were produced by a single-screw extruder. The mechanical strength tests were performed, including the impact tensile test and three-point bending fl exural test. Afterwards, the samples were tested for biodegradability under anaerobic conditions. The methane fermentation process was carried in a laboratory bioreactor under thermophilic conditions with constant mixing of the batch. All samples proved to be highly susceptible to biodegradation during the experiment, regardless of the fl ax fi ber share. The biogas potential was about 600 ml·g-1, and the methane concentration in biogas ranged from 66.8 to 69.6%. It was found, that the biocomposites can be almost completely utilized in bioreactors during the biodegradation process. The energy recovery in the decomposition process with the generation of signifi cant amount of methane constitutes an additional benefi t.

In this paper, a model of an electromagnetic system with two levitating magnets is presented. Modeling was performed using the results of experiments. The data obtained make it possible to fit the magnetic forces between two magnets using a 5th order polynomial. The time series show that dry friction constitutes an important part of damping forces. The differential equations of motion consider strong nonlinearities of magnetic and damping forces. These terms cause the nonlinear hardening effect. The energy recovered by magnetic induction is dissipated in the resistors. Numerical simulations show that resistance has an impact on magnet dynamics and energy recovery. From the resonance characteristics obtained, optimal resistance is determined when energy recovery is the highest.

The main goal of the research presented in this paper is to find an analytical solution for an electromagnetic energy harvester with double magnet. A double magnet configuration is defined as a structure in which two magnets, either attracting or repelling, are positioned at a constant distance from each other. Analytical dependencies that govern the shape of electromechanical coupling coefficient curves for various double magnet configurations are provided. In the subsequent step of the analysis, resonance curves for its vibrations and the corresponding recovered energy were determined for the selected dual magnet settings using the harmonic balance method. These characteristics enabled us to ascertain the optimal resistance and estimate the maximum electrical power that can be harvested from the vibrations of the double magnets.

The article analyzes the risk factors related to the energy use of alternative fuels from waste. The essence of risk and its impact on economic activity in the area of waste management were discussed. Then, a risk assessment, on the example of waste fractions used for the production of alternative fuel, was carried out. In addition, the benefits for the society and the environment from the processing of alternative fuels for energy purposes, including, among others: reducing the cost of waste disposal, limiting the negative impact on water, soil and air, reducing the amount of waste deposited, acquisition of land; reduction of the greenhouse effect, facilitating the recycling of other fractions, recovery of electricity and heat, and saving conventional energy carriers, were determined. The analysis of risk factors is carried out separately for plants processing waste for alternative fuel production and plants producing energy from this type of fuel. Waste processing plants should pay attention to investment, market (price, interest rate, and currency), business climate, political, and legal risks, as well as weather, seasonal, logistic, technological, and loss of profitability or bankruptcy risks. Similar risks are observed in the case of energy companies, as they operate in the same external environment. Moreover, internal risks may be similar; however, the specific nature of the operation of each enterprise should be taken into account. Energy companies should pay particular attention to the various types of costs that may threaten the stability of operation, especially in the case of regulated energy prices. The risk associated with the inadequate quality of the supplied and stored fuels is important. This risk may disrupt the technological process and reduce the plant’s operational efficiency. Heating plants and combined heat and power plants should also not underestimate the non-catastrophic weather risk, which may lead to a decrease in heat demand and a reduction in business revenues. A comprehensive approach to risk should protect enterprises against possible losses due to various types of threats, including both external and internal threats.

The Authors present the problems of theoretical analysis and experimental research related to the possibilities of energy recovery in selected phases of operating and running cycles of self-driven crane. Heavy machinery powered by diesel engines is a source of solid toxic emissions. In order to limit these emissions, one install filters and filter regeneration systems. According to the concept presented here, the recovered energy might be utilised for regeneration of these filters by burning off accumulated solid particles (soot). Mechanical energy would be the power source to drive DC generators - the mechanical-into-electric energy converters. Filter's heating resistors, acting as the generators' load, would radiate a power of 3-;-5 MJ to initiate burning of soot in the filter. The calculations of energy consumed during sheave block lowering phase were made for three different lifting capacities taking into account the boom length and crane reach. Three running cycles of the crane: highroad, urban and off-road ones were also analysed. The time functions of variations of crane running speed and power of motion resistance at driving wheels were found. The results provided the background for determination of theoretical values of energy to be regained during braking phase of the analysed cycles. The structure and operation of experimental stands was discussed. The stands contain units that, at proper size factor, represent the processes that occur in real cranes and that are related only to energy recovery. Computer software for system simulation, control and measurement was described. Measurement results and result analysis are presented. The value of energy found theoretically was compared with the energy recovered during experimental tests. The paper also contains simplified kinematic schemes of selected units of crane lifting and driving systems, including an additional DC generator. This concept, however, needs verification in future design solutions.