Jakub Pulka

Approximately 30% of the food produced worldwide is wasted, and a substantial share of municipal food waste still contains non-biodegradable packaging material after sorting. This study investigated an aerobic biodrying process for reducing the moisture content of mixed food-waste fractions, containing varying proportions of green biomass, vegetables, kitchen waste, and packaging-derived plastics, in order to increase their calorific value and obtain a refuse-derived fuel (RDF). Four substrate variants (K1–K4, including a control without added plastics) were biodried in laboratory-scale bioreactors. Process temperatures exceeded 70 °C in all variants, and the addition of plastics increased both the cumulative and the average temperature relative to the control. The plastic fraction recovered after biodrying showed the largest increase in calorific value, reaching over 15 MJ∙kg⁻¹, while the AT4 respiration activity of the separated compost fraction decreased to around 10 mg O₂ g⁻¹ DM in all variants, indicating good storage stability. The results suggest that pre-treated plastics did not adversely affect the biodrying process and, owing to their structuring properties, may support biological decomposition of the remaining biomass; these preliminary, single-run findings should be confirmed in replicated trials.

In recent years, Poland has seen a rapid increase in installed capacity in the Renewable Energy Sources (RES) sector. This increase mainly concerns weather-dependent sources such as PV and wind installations, whose intermittent operation destabilizes the Polish power system (PPS). The solution to...

Attaining sustainable development is one of the most important challenges of the 21st century

The aim of the work was to analyze the impact of biochar produced under various production conditions on the course of the dark (hydrogen) fermentation process. A series of experiments were planned, in which the starting material was digestate from a functioning agricultural biogas plant. Changes in the physicochemical properties and microstructure of biochar obtained in the manufacturing process with different parameters were also analyzed. Another issue analyzed was the size and dynamics of the gas production during dark fermentation with the use of various types of auxiliary material. This work showed that increasing the temperature and holding time during the production of biochar from digestion pulp improved the dynamics of biohydrogen production during the process of dark fermentation. The results of this research can be used in industrial research to optimize the process of biohydrogen production using biochar.

Digestate from a biogas plant can be a valuable organic and mineral fertilizer. Quantitative proportions of co-substrates used in three agricultural biogas plants in Poland were analyzed. The composition of digestates was examined and large differences in the content of macronutrients were found,...

The impact of the modification of the plasticizing system of the TS-45 single-screw extruder (by ZMCh Metalchem, Gliwice, Poland) with L/D = 12 is discussed in the article. The modification involved the reconfiguration of the extruder screw to achieve certain selected physical characteristics...

Energy production from renewable sources is one of the main ways to fight against global warming. Anaerobic digestion process can be used to produce biogas containing methane. In the light of the growing demand for substrates, a variety of raw materials are required. These substrates should be suitable for anaerobic digestion, and processing them need to provide the desired amount of energy. This paper aims to discuss the agricultural biogas market in Poland, its current state, and the possibility of development during energy transformation, in particular in terms of using waste as a substrate for energy production. In February 2022, there were 130 agricultural biogas plants registered in Poland. On the other hand, in 2020, 4,409,054.898 Mg of raw materials were used to produce agricultural biogas in Poland. Among all the substrates used, waste played a special role. With the right amount of raw materials and proper management of a biogas plant, it is possible to produce electricity and provide stable and predictable heat supply. Bearing in mind the development of the Polish and European biogas markets, attention should be paid to ensure access to raw materials from which chemical energy in the form of biogas can be generated. Due to limited access to farmland and the increasing demand for food production, one should expect that waste will be increasingly often used for biogas production, especially that with high energy potential, such as waste related to animal production and the meat industry.

Diary production is steadily increasing worldwide, as evidenced by a 1.6% increase in milk production. Cattle headcount in Europe amounts to 75.6 mln, with Poland heaving more than 10% of the EU population. Such a significant production is yielding massive waste and animal by products, mainly cow manure. Storage and utilization of these byproducts may result in unwanted emissions of greenhouse gasses such as methane, carbon dioxide, and other potentially dangerous compounds like ammonia. Proper manure management and utilization of animal by-products and carcasses could successfully mitigate GHG emissions. One of the main means of utilization that could be implemented in Poland is the fermentation process and biogas production. Such an approach is beneficial not only due to energy production but also because of fertilizer production in form of digestate. To allow and maximize this process deep investigation is necessary, because of the different properties of a vast type of products, for example, the biogas yield of by-products ranges from 20 to more than 500 m3 of biogas per Mg. Because of that, the fermentation process of the above-mentioned materials must be properly conducted. Mainly substrate mix and process prosperities must be carefully assessed. In this paper, the steps necessary to implement mentioned solution will be presented as well as projected outcomes.

The aim of the work was to present the role of composting as one of the simple and cheapest methods to reduce GHG emissions from cow manure - conclusions from the MilKey and MELS projects. The article contains both the results of some studies analyzed within the above projects, as well as the methodology of conducting composting studies. The method of managing animal waste by composting or co-composting has been known for a long time and used in many places around the world. However, this is not always done in an appropriate way, both economically and ecologically. Improper storage of manure, its holding time, the way it is applied to the field and finally its use as fertilizer are quite significant for ammonia and greenhouse gases (GHG) emissions. These types of issues are typical of areas of intensive animal production, where farmers use natural fertilizers (slurry, manure) to increase the humus layer on agricultural fields. Most developing or still underdeveloped countries (including Poland) are undergoing intensive changes in the area of sustainable processing of natural fertilizers. The modern rules of the new Common Agricultural Policy of Poland, defined for 2021-2027, provide for the transition of farmers to sustainable agricultural production. One of the key elements for Polish farmers will be the reduction of greenhouse gas emissions from farms by introducing agricultural techniques (e.g. through appropriate nutrition or agrotechnical treatments). In addition, increasing market pressure is expected due to consumer expectations to confirm the sustainability of animal production.