Landfill leachate circuits that operate without discharge, by recirculating aerated leachate onto the waste mass, are widespread in South-East Europe, yet their long-term behaviour is rarely documented with sample-level data. This study reports a six-year (2020–2025) seasonal monitoring campaign at a sanitary landfill in northern Serbia (alluvial aquifer of the Sava River, transboundary Danube basin) and re-examines it with a transparent multivariate protocol. Seventy-two leachate samples (collection well, aeration lagoon, sedimentation lagoon; n = 24 each, 30 parameters), 28 realised surface-water campaigns, and six years of groundwater summaries were evaluated by principal component analysis/factor analysis (PCA/FA, Varimax normalized), hierarchical cluster analysis, PERMANOVA, non-parametric paired tests and, for benchmarking, supervised machine learning. The pooled leachate model (n = 72; 21 variables; KMO = 0.700; Bartlett χ2 = 956, p < 0.001) retained four factors by parallel analysis, explaining 61.6% of total variance; after rotation the factors accounted for 27.7%, 14.3%, 10.4%, and 9.3%. Factor 1 grouped organic load with particle-reactive metals (COD, BOD5, Fe, Ni, Cr, As, Zn), Factor 2 a reduced sulfur–fluoride–BTEX signature, Factor 3 temperature-driven nitritation, and Factor 4 a nitrate–manganese redox contrast. Crucially, paired campaign-by-campaign comparison showed no removal of the dominant pollutants along the circuit. Median COD, BOD5 and NH4-N were not lower in the sedimentation lagoon than in the collection well, while pH rose from 8.08 to 8.75 (p < 0.001); only Cu, Pb, NO3-N, and NO2-N decreased significantly. The circuit therefore homogenises and concentrates dissolved load rather than removing it. Downstream surface water was significantly enriched in electrical conductivity (+110 µS/cm), total dissolved solids, NH4-N, and NO2-N relative to upstream (Wilcoxon, p < 0.05), and groundwater showed episodic conductivity up to 12,760 µS/cm and NH4-N up to 102 mg/L. Cytotoxicity (MTT) confirmed biological relevance, with MRC-5 viability falling to 37% after 24 h exposure to 50 vol.% groundwater (Pw3) versus 60% in A549 cells. A random-forest classifier separated circuit units far better than PCA-based discrimination (76.4% versus 54.2% cross-validated accuracy) and distinguished the 2020–2021 pandemic period from 2022–2025 with 94.2% accuracy, a period effect also confirmed by PERMANOVA (R2 = 7.2%, p < 0.001). The results indicate that closed-loop recirculation without an engineered discharge barrier transfers, rather than eliminates, contaminant load, and that after-care of such systems requires mass-balance monitoring and polishing treatment.

This paper explores the possibilities of applying renewable energy sources (RES) in rural areas of the Republic of Serbia, aiming to increase energy efficiency, reduce environmental pollution, and promote sustainable development. By analyzing the characteristics of rural areas, demographic indicators, and the current state of agricultural holding, the paper identifies key potentials and challenges in the use of RES. Special attention is given to solar energy, wind energy, biomass, biogas, and geothermal energy, as well as their technical possibilities and practical applications in agriculture and households. Based on a survey on the awareness of rural populations regarding renewable energy sources, the study analyses attitudes, knowledge levels, and readiness for investment in RES. The results show significant potential for the development of renewable energy in rural areas of Serbia, emphasizing the need for greater education, institutional support, and financial incentives. This paper concludes that integrating renewable energy sources can contribute to the development of sustainable and energy-independent rural communitas.

This study assesses the water quality of the upper course of the Krivaja River in northern Serbia, part of the Tisza and Danube catchments. The analysis focuses on a 2 km stretch with the highest pollution levels, using monitoring data from 2014 to 2017 and synthetic surface water pollution indicators. A total of 96 samples were collected at 6 different surface water sampling points, 16 per site. Wastewater were collected from 4 sampling points, 16 before its inflow into the Krivaja River and 32 as effluent. Surface water sampling where taken in accordance with SRPS EN ISO 5667-3:2007, and wastewater with SRPS ISO 5667-10: 2007 methods. Analyses of metals in water samples were carried out by atomic absorption spectroscopy, and nitrogen and phosphorus compounds were measured by UV spectrophotometry. Comparison with national standards revealed extremely high pollution levels: COD exceeded limits by 43 times, BOD5 by 76 times, total nitrogen by 23 times, and N-NH3 by 211 times. Nickel concentrations also surpassed the European Union Directive 2013/39/EU limits. The Nemerow index values (27.6-102) highlighted heavily polluted discharge sources, such as animal feed production. Cluster analysis confirmed these findings. Key pollutants include organic indicators (COD, BOD5, KMnO4), nutrients (NO2 -, NO3 -, TN, N-NH3), TSS, Cl-, and Fe. Metals (Mn, Zn, Ni, Pb, Cu, Cr, Cd, As) showed minor variations, minimally impacting the overall score. Poultry wastewater exhibited significant quality fluctuations, ranging from moderately to heavily polluted (PIW = 4.05-8.20). The primary cause of poor water quality is inadequate wastewater treatment in the region. Urgent measures are needed to mitigate pollution and restore the Krivaja River's ecological integrity.

This paper explores the integration of Circular Economy (CE) principles and Industrial Ecology (IE) practices as a means to enhance sustainability and resource efficiency across various industries. The circular economy shifts away from the traditional linear model of “take, make, dispose,” promoting a closed-loop approach that minimizes waste and prolongs the lifecycle of products through reuse, recycling, and remanufacturing. Industrial ecology, on the other hand, emphasizes industrial symbiosis, where waste or by-products from one process serve as inputs for another, mimicking natural ecosystems. The study employs a qualitative methodology, analysing secondary data from industries such as automotive, energy, and electronics, revealing how CE and IE practices lead to significant reductions in resource use, waste generation, and carbon emissions. Results show that industries adopting CE and IE principles achieve improved efficiency and environmental sustainability, with specific examples of resource savings and reductions in CO2 emissions. Despite challenges in implementation, this research highlights the potential of CE and IE to foster innovation, economic growth, and environmental resilience. The paper concludes by stressing the importance of collaboration between governments, businesses, and academia to advance these concepts and address the environmental challenges of the 21st century.

Searching relevant literature sourcesit was found that the determination of fire hazard zones in warehouses is not sufficiently researched and studied. This paper aims to present a new methodological approach concerning the mentioned issue. Based on the COPRAS multi-criteria decision-making method, a new method was developed for the precise determination of potential zones where there is a risk of fire. The advantage of the described method is that it enables quick and easy determination of all orientation zones of fire risk in a quick and simple way. The method requires fewer hardware resources compared to the existing ones and enables the display of the warehouse space in the form of a 3D model with calculated fire hazard zones. The mentioned procedure represents the first step when planning the layout and arrangement in the warehouse itself. The effectiveness of the proposed method was confirmed through a suitable numerical example.

The growing negative impact of human activities increases the effect of climate change. People must adapt and change their behaviour and attitudes towards solving current environmental problems and preventing new ones. Non-formal education, such as educational workshops on environmental topics, could give results in the short term. In this research, workshops on energy efficiency and climate change were used to increase environmental knowledge and to track changes in environmental attitudes regarding generational affiliation. Workshops for pupils were held in selected primary schools in Vojvodina region in Republic of Serbia. The achievement of workshops on energy efficiency and climate change attitudes at pupils and transfer of the knowledge gained at workshops to their parents were considered through the following three attributes: perception of personal knowledge and awareness, intensity of intergenerational communication, and knowledge. Assessment of the workshops’ achievements was accomplished by preliminary and final survey, and results were compared using descriptive and inferential statistical methods. Key findings in this research revealed that there is a significant potential for changes in the attitudes by raising awareness through knowledge in pupils, but also at parents, through intergeneration communication and knowledge transfer.

Considering that the determination of fire hazard zones in warehouses is not sufficiently researched and studied, this paper aims to present a new methodological approach concerning the mentioned issue. Based on the COPRAS multi-criteria decision-making method, a new method was developed for the precise determination of potential zones where there is a risk of fire. The advantage of the described method is that it allows the quick and easy determination of all-orientation fire risk zones. The method requires fewer hardware resources compared to the existing ones and enables the display of the warehouse space in the form of a 3D model with calculated fire hazard zones. The mentioned procedure represents the first step when planning the layout and arrangement in the warehouse itself. The effectiveness of the proposed method was confirmed through a suitable numerical example.

The purpose of this paper is to show the results of Risk-Based Inspection (RBI) analysis conducted in a refinery plant in the Middle East by applying slightly modified methodology for an RBI. Due to the complexity of the refinery, a summary of identified damage mechanisms and discussion regarding barriers are shown in chosen representative units. Application of the Innovative approach in the implementation of RBI process will be presented by defining active and passive damage mechanisms, with the emphasis on damage mechanism identification for energy equipment. Finally, the main result of application of Innovative approach lies in the fact that one can setup the system that can be more useful than the traditional approach to an RBI analysis in a way that specific time frame for triggering an RBI review can be better defined. This approach was developed and successfully applied for an RBI study covering six units where over 1100 pieces of major equipment and more than 15000 pieces of piping systems were analyzed.

This work presents the results of the first Serbian monitoring campaign performed to assess the occupational exposure of petrochemical industry workers to benzene (B), toluene (T), ethylbenzene (E), and xylene (X), known collectively as BTEX. The following urinary biomarkers were investigated: phenol, hippuric acid, o-Cresol, p-Cresol, and creatinine. BTEX compounds were collected in 2014 using Casella passive samplers. Multivariate statistical analysis was performed to put in evidence the correlation between the BTEX measured in air and the concentration of urinary biomarkers. While the results indicate an elevated presence of benzene in the air in the working environment studied that surpasses the national and European Occupational Exposure Limits (OEL), the levels of the remaining (TEX) parameters measured were below the OEL. The high relative standard deviations (RSD) for the concentrations of each BTEX compound (68–161 mg m−3) point toward an intensive occupational exposure to BTEX. This was confirmed by relevant urine biomarkers, particularly by the mean values of phenol, which were ten and fourteen times higher than the ones found in the control group (14–12 mg g−1 of creatinine). On average, workers are at a higher risk of developing cancer (6.1 × 10−3), with risk levels exceeding the US EPA limits. Benzene levels should therefore be maintained under tight controls and monitored via proper urinary biomarkers.

Pyrolysis is an optimal thermochemical process for obtaining valuable products (char, oil, and gas) from waste tires. The preliminary research was done on the three groups of samples acquired by cutting the same waste tire of a passenger vehicle into cylindrical granules with a base diameter of 3, 7, and 11 mm. Each batch weighed 10 g. The heating rate was 14 °C/min, and the final pyrolysis temperature was 750 °C, with 90 s residence time. After the pyrolysis product yields were determined for all of the three sample groups, further research was performed only on 3 mm granules, with the same heating rate, but with altered final pyrolytic temperatures (400, 450, 500, 550, 600, 650, 700, and 750 °C). The results of this study show that thermochemical decomposition of the waste tire sample takes place in the temperature range of 200–500 °C, with three distinct phases of degradation. The highest yield of the pyrolytic oil was achieved at a temperature of 500 °C, but further heating of volatile matters reduced the oil yield, and simultaneously increased the yield of gas, due to the existence of secondary cracking reactions. The analysis of pyrolytic oil and char showed that these products can be used as fuel.

Landfilling as the most common type of waste disposal in low income countries causes various environmental issues due to gas emission.Since little attention was paid to air pollution from landfills, due to the lack of appropriate data, the aim of this paper is to establish a model for a landfill prioritization according to the methane risk assessment in developing countries like Serbia.Considering that the landfill methane risks (i.e.emission and atmospheric distribution and dispersion) depends on various parameters (criteria), to accomplish the objective, the authors carried out: a preliminary identification of the key criteria based on the available data, appointed criteria importance by Analytical Hierarchy Processes (AHP), established landfill impact category and proposed the final prioritization of landfills by Compromise Programing (CP) method.The proposed model was successfully tested and applied to eight landfills in South Backa District in the Republic of Serbia.Due to the lack of financial resources, the development of a model for a landfill prioritization according to the methane risk assessment presented in this paper could be a significant foundation for decision-makers in order to establish the priorities for undertaking the necessary control and remedial measures.

Serbia, as a developing country and EU accession country, faces many challenges. One of the key areas identified as the most complicated problem in the negotiation process is the issues of environmental protection and improvement, including the energy sector. Since population in Serbia is concerned because of poor living standards, high unemployment rate, and other social issues it could be questioned what is their concern and awareness about climate change since it is a realistic and visible phenomenon that is hard for someone to ignore and neglect. This paper presents some of the results of a survey conducted among adults in rural and urban parts of the Autonomous Province of Vojvodina on their perception, awareness, and knowledge about climate change issues. The research/survey also examined the specific actions that respondents would take as a personal contribution to mitigating the effects of climate problems. The results indicate that respondents have a high awareness of climate change, but the knowledge on climate change is relatively low even though the respondents graduated from faculty (about 52%).

In the oil and gas industry hydrogen is used in a large number of processes, mostly in hydroprocessing units such as hydrotreating, hydrocracking and other refining processes that increase the hydrogen-to-carbon ratio. To satisfy the need for H-2, refineries usually have a dedicated Hydrogen Production Unit (HPU). Given the wide range of processes that HPU supplies and the fact that cost of operation of this kind of unit is rather high, it stands to reason that any kind of interruption in unit operation will affect the whole refining process. From Risk Based Inspection (RBI) point of view, HPU can be a very challenging unit to deal with, primarily due to the wide range of operating processes conditions as well as different operating fluids. As a result of applying the innovative methodology for risk assessment, it is shown that significantly higher number of damage mechanisms are identified in regard to the number of damage mechanisms that would be identified by applying traditional methodology, due to the fact that both active and passive damage mechanisms are identified. Concept of barriers such as measures that are able to restrict, reduce or preferably eliminate damage mechanisms identified in HPU are introduced and discussed. Innovative methodology was successfully applied in the case of a refinery in the Middle East.

When implementing the method for quantitative risk analysis, usually based on RBI (Risk Based Inspection), conditions which directly influence the identification of damage mechanisms are defined at the beginning of the analysis. Thus, conducted analysis applies to the exact parameters and very specific combinations of conditions and damage mechanisms. The question arises as to whether such an analysis and its results may represent initial data for some subsequent analysis that can be carried out in the following period, regardless of the reasons for the implementation. The extension of the methodology from the one shown in the ASME PCC 3 standard is to identify both active and passive/potential damage mechanisms and the conditions under which passive can be activated. This addition to the methodology is successfully applied in case of a Middle East refinery, and as a representative example, a typical amine regeneration unit present in all modern gas or oil refineries, specifically the part of the unit with lean amine, is shown.

Implementation of the methodology for quantitative risk analysis, usually based on RBI (Risk Based Inspection), is heavily influenced with the methods for damage mechanisms identification. Same analysis may give various results depending on the adopted operating parameters in a given time. The question arises as to whether such an analysis and the results of the analysis may represent initial data for some subsequent analysis that can be carried out in the following period, regardless of the reasons for the implementation. The aim of this paper is to demonstrate application of a modified methodology for damage mechanism identification. The extension of well-known methodology shown in ASME PCC 3 standard is in the manner in which the damage mechanisms are identified: distinction will be made from active and passive (potential) damage mechanisms, and as well as documentation of conditions under which passive damage mechanisms can become active. Concept of barriers will be also presented.

Waste disposal is a common practice in Serbia. Landfills are largely unregulated and most commonly, waste is disposed without pre-selection so it represents an uncontrolled methane source of emission. Methane is a greenhouse gas which is estimated to have 20 times higher potential for global warming than carbon dioxide. In this paper, based on the available data on the level of emissions from the landfill, the modeling of methane dispersion after emission was performed for the periods of the dominant meteorological conditions whereby the quantification and characterization of the methane behaviour and its dispersion into the ambient air was carried out. Analysis of the modelled methane concentrations showed that maximum concentration of 7478.9 μg/m3 was reached at the distance of 466.6 m from the landfill itself, with no significant influence on the nearest settlements.

This paper outlines the approach that can assist decision makers to have first preliminary insights regarding costs of complying with requested European Union municipal waste management goals in transition and developing countries. Serbia, as a joining member of European Union, must confront itself with the challenges resulting from European Union waste management directives. Implementation of waste separation units and the construction of sanitary landfills is already in place in Serbia. However, new waste management practice will need additional transformation and will require implementation of waste treatment technologies for additional management of generated waste. Implementation of analyzed best available technology/techniques for waste treatment can support the country’s effort in reaching the policy goals. However, the question here is how much will the implementation of additional waste treatments influence the overall waste management costs? Results of the scenario’s financial viability show that composting and sanitary landfill are the most viable solutions regarding the costs, even under increasing discount rates. Although different discount rates influence the overall gate fees and net present values, the level of affordability for different scenarios remains the same.