Maize crop residues have great significance, particularly in developing countries, where the harvest of maize ears and their natural drying is widely applied. After drying and grain threshing, maize cobs are available for energetic use on farmers? yards. Shortcomings for their energetic utilization by combustion, in comparison with wood, are higher contents of potassium, chlorine and nitrogen, and lower ash softening point. Tests in small wood chip boilers showed that the size of maize cobs should be reduced in order to facilitate better combustion and feeding with commonly used screw conveyors. Desirable length of particles should be 1-1.5 of their diameter. Within the framework of the Eureka project, a low-cost maize cobs crusher was developed and tested. It consists of a drum with six rows of knives, stationary comb-like knives and a screen situated below the drum. The test resulted with working parameters that enable appropriate size reduction. Analyses of crushed material showed that over 80% of particles were in the range of 3.15-45 mm, less than 1% smaller than 1 mm, and less than 1% larger than 63 mm. This granulation is comparable with size class P45 for wood chips in accordance with standard DIN CEN/TS 14961. Further investigations should focus on improving the combustion facilities, in order to avoid formation of ash slag, and keeping exhaust gas characteristics within values defined by legislation.

The production of essential oils generates substantial quantities of solid post-distillation residues, a largely unutilized waste stream rich in bioactive compounds (e.g., phenolics, flavonoids) as well as polysaccharides. Managing this organic waste presents both environmental and economic challenges. This review critically examines environmentally friendly green innovations and resource-efficient technologies within circular bio-economy strategies for valorizing these residues, focusing on four primary conversion pathways: physico-mechanical, thermochemical, biological, and chemical methods. We highlight their potential for practical applications, including the extraction of active compounds for food, cosmetic, and pharmaceutical industries, utilization in agriculture, incorporation into construction materials and wastewater treatment. Despite these opportunities, wider industrial adoption remains limited by high processing costs and the lack of scalable, cost-effective technologies. Key research gaps included the need for methods applicable at the farm level, optimization of the residue-specific conversion process, and life-cycle assessments to evaluate environmental and economic impacts. Addressing these gaps is crucial to fully exploit the economic and ecological potential of post-distillation solid residues and integrate them into sustainable circular bio-economy practices through various processes.

The aim of this paper is to analyze renewable energy sources (primarily untapped biomass potentials) in the Autonomous Province of Vojvodina in the Republic of Serbia, which, when used for energy purposes, could significantly reduce energy dependence on fossil fuels. The idea of using biomass in Vojvodina emerged about ten years ago, but it is estimated that currently only 5% of total biomass potential, the most significant source of renewable energy in the region, is being used. This paper re-emphasizes the idea of focusing Vojvodina’s energy policy on its own energy resources, which are readily available and renewable, but each year is either burned in the fields or left to rot. The paper will outline the total potential of raw materials, the form in which they are found, and the possible means of utilizing them. It will also provide an overview of energy in Vojvodina with a particular focus on the portion of renewable sources as a neglected potential within overall energy consumption. In addition to energy potential, this paper also points to the benefits for heating and the environment that would be created through increased use of biomass in the process of energy production.

The effect of COVID-19 lockdown (LD) on many ambient air pollutants (NO, NO₂, PM_2.5, PM₁₀, O₃ and SO₂) was assessed for the first time in the Western Balkans with an innovative approach that evaluates a variety of factors including the stringency of the LD measures, the type of location, the pollution sources, the correlation with traffic fluxes and the meteorology. To that end, observations from 10 urban sites were compared with historical time series. The time window 1 February–30 May 2020 was classified in sub-periods on the basis of the stringency of the circulation restrictions. NO₂ and O₃ are the pollutants most affected by restrictions to population circulation due to lockdown during the first phase of the COVID-19 pandemic, and are well correlated with traffic fluxes. A reduction in fine particulate matter (PM_2.5 and PM₁₀) concentrations is observed in all sites only during the full LD periods, while the relation between SO₂ average and maximum hourly concentrations and LD periods in industrial and traffic sites vary from site to site. The reduction in NO₂ concentrations during the LD resulted in a reduction in mortality associated with air pollution in the largest cities, while the interpretation of the changes in O₃ and particulate matter is less clear.

The aim of this study was to comprehensively characterize lavender pellets produced from post-distillation residues and evaluate their multifunctional valorization potential. Physicochemical properties, including moisture, ash, heating value, organic matter, total and organic carbon, macro- and micronutrients, potentially toxic heavy metals, polyphenols, microbiological safety, and nutritive composition, were assessed. The pellets demonstrated an energy content comparable to other agricultural residues, with a higher heating value of 18,900 kJ/kg and a lower heating value of 16,603 kJ/kg. High organic matter (87%) and a slightly acidic pH support soil moisture retention, while favorable macronutrient levels enhance their suitability as a soil amendment. Water-based extractions (infusion and decoction) achieved higher yields (15.60–21.66%) than ethanol (13.04%) and more effectively recovered bioactive polyphenols, particularly rosmarinic and chlorogenic acids. Low moisture and water activity ensured storage stability and minimal microbial growth, which was confirmed by microbiological safety tests. Nutritionally, pellets contained moderate protein (9.38%), high cellulose (33.38%), and low fat (2.18%), with total amino acids of 8.91 g/100 g and 36.7% essential amino acids, along with a favorable fatty acid profile rich in polyunsaturated fractions. Overall, these findings highlight lavender pellets as a sustainable resource for energy, soil improvement, bioactive compound recovery, and complementary animal feed within circular economy frameworks. However, future research should focus on investigating whether residual compounds remain in lavender residues that could exert antifeedant or phytotoxic effects. Additionally, the potential for the sequential valorization of lavender residues should be explored, initially through the extraction of bioactive phenols, followed by pellet production for use as fuel or soil amendments. This approach would enable multiple cascading uses and maximize their contribution to comprehensive circular economy strategies.