Mycelium-based materials are emerging as promising bio-derived alternatives to animal and synthetic leather. However, their practical implementation is limited by insufficient mechanical strength and high surface hydrophilicity, which compromise dimensional stability and durability under humid conditions. This study investigates post-processing strategies aimed at enhancing structural integrity and improving surface hydrophobicity – an essential parameter to increase water resistance and extend service life – of Trametes versicolor mats produced through liquid-state surface fermentation (LSSF). A preliminary assessment showed that hot pressing increased the ultimate stress of glycerol-treated sheets from 0.31 ± 0.06 to 0.45 ± 0.06 MPa, confirming its suitability as a standard consolidation step. Subsequently, sorbitol- and citric acid-treated mats were coated with seven bio -based formulations, including proteins, polysaccharides, shellac, and wax–oil blends, and evaluated through static water contact angle (WCA) measurements. The uncoated mat exhibited the highest hydrophobicity (99.8 ± 15.0)°, while coated samples showed WCAs ranging from 65.1° (corn zein) to 95.3° (wax–oil balm). Coatings rich in hydrophobic long-chain molecules yielded the best water repellence, whereas protein- and polysaccharide-based films primarily altered surface texture without enhancing wettability. These results highlight the importance of formulation chemistry – particularly plasticizer content – in determining surface hydrophobicity, and provide a foundation for the development of scalable, fully bio-based surface finishing treatments for fungal leather-like materials.
Biomass diversification in district heating is driven by resource constraints and sustainability requirements under European Union policy, yet variability in fuel properties complicates procurement and operational planning. This study evaluates nine biomass fuels available on the local market, including wood chips, residues from intensified forest harvesting, and alternative biomass blends, to link fuel quality with economic and environmental performance. Fuels were characterized by proximate and ultimate analysis, calorific value, ash melting temperature, and chemical composition, and ash utilization potential was assessed through oxide mapping and heavy-metal analysis. Combustion tests were conducted in a large-scale moving-grate boiler under real operating conditions, with flue-gas measurements used to calculate efficiency and heat losses. WC3 achieved the highest net calorific value due to low moisture, also the highest combustion efficiency and lowest particulate matter concentration in flue gas, while WM3 and WM4 showed severe CO peaks and combustion efficiency losses under tested conditions. WM3 had the highest ash content and lowest melting point, while WM4 contained a large fines fraction, raising dust and segregation concerns. Heavy-metal concentrations were lowest in WC3 and highest in WR2.
The dairy sector faces increasing pressure to reduce environmental impacts while maintaining nutritional quality and product diversity. Cheese production is particularly complex, as it involves a wide range of processing technologies and energy demands, from fresh cheeses to long-ripened products. This study presents an evaluation based on Environmental Product Declarations and Life Cycle Assessment applied to fourteen dairy and plant-based products, including milk, fresh products, cheese, and plant-based alternatives. Environmental impacts are expressed as Global Warming Potential (GWP, kg CO(2)eq/kg product) and disaggregated across upstream, core, and downstream phases. For studies with limited system boundaries, downstream proxy values, covering distribution, household refrigeration, and packaging end-of-life, were estimated using a harmonized set of assumptions to ensure cross-product comparability. To move beyond mass-based functional units, impacts are also expressed relative to a Nutrient Density Unit (NDU) encompassing energy, protein, fat, carbohydrates, and calcium, key nutrients in which dairy products excel. Further analyses examine the influence of post-farm processing efficiency through five decarbonization scenarios, including energy efficiency improvements and industrial heat pump electrification under varying electricity mixes, applied to four representative products and address the robustness of the nutritional metric through a simplified Nutrient Rich Food index in which fat is treated as a nutrient to limit. Results show that while mass-based GWP favours minimally processed and plant-based products (0.72-1.6 kg CO(2)eq/kg) over longripened cheeses (9-20 kg CO(2)eq/kg), nutritional normalization substantially narrows, and in some cases reverses, this gap: mean GWP/NDU values are 39 for milk, 34 for fresh dairy, 30 for cheese, and 12 for plant-based alternatives, reducing the category-level difference from approximately thirteen-fold to roughly two-and-a-half-fold. Processing decarbonization reduces GWP/NDU by 4-24 % depending on product type, with UHT milk showing the strongest response and long-ripened cheeses the most limited, given the dominance of upstream agricultural emissions. The NRF-based robustness check confirms that relative product rankings remain broadly stable under alternative nutritional metrics. This framework supports transparent sustainability communication, product benchmarking, and evidence-based decision-making in the food sector.
The problems of climate change, especially the greenhouse effect caused by transport exhaust gas emissions, make the issue of finding alternatives to fossil fuels increasingly urgent. One such alternative is biodiesel. The valorisation of industrial biomass based by-products such as soapstock, generated during vegetable oil refining, supports both waste reduction and sustainable biodiesel production. This study investigates the acidulation of rapeseed soapstock to obtain acid oil - a mixture of free fatty acids and glycerides suitable for advanced biodiesel synthesis. The effects of acid type (concentrated sulphuric acid, 50 % sulphuric acid, 25 % citric acid), pH (2-7), and temperature (20, 45, 70 degrees C) on purified acid oil yield and phospholipid removal were examined under controlled laboratory conditions. Rapeseed soapstock was acidified till defined pH using chosen acid at set temperature. Then extraction with cyclohexane followed by purification with cold acetone yielded acid oil. The optimal acidulation parameters were achieved with concentrated sulphuric acid at pH 5 and initial soapstock temperature around 20 degrees C, producing 34.7 % of purified acid oil. These results demonstrate that optimized acidulation of rapeseed soapstock provides a cost-effective route for converting industrial waste into a viable feedstock for biodiesel synthesis, contributing to circular bioeconomy principles and the reduction of fossil fuel dependence.
The maritime sector faces increasing regulatory and economic pressure to reduce greenhouse gas emissions, requiring region-specific evaluation of alternative marine fuels. This study examines the short-term (10-15 years) usefulness of alternative fuels in the Baltic Sea Region through an integrated assessment combining literature review, regional trade analysis using Eurostat and HELCOM data, vessel segmentation, infrastructure readiness analysis, and techno-economic modelling. A GT-LOA conversion formula is derived from ship databases to improve vessel-based fuel demand estimation and support infrastructure compatibility analysis. The results identify e-LPG, e-LNG, green methanol, ammonia, and biofuels as the most viable fuels for the transition period, emphasizing the role of infrastructure availability, regulatory cost mechanisms, and vessel size distribution in shaping adoption pathways. The findings indicate that the Baltic Sea Region is entering a critical transitional phase in which alternative fuels can be deployed through phased implementation strategies combining transitional and zero-carbon options. The study provides decision support for policymakers, port authorities, and industry stakeholders regarding fuel investment planning, infrastructure development, and emerging maritime energy business opportunities.
Low-quality biomass (LQB) is an abundant feedstock for small-scale heat generation, but its variable composition often leads to unstable combustion and elevated emissions in domestic boilers. This study assesses the combustion behaviour of 18 pelletized LQB feedstocks using a 25-kW boiler operated under controlled conditions. The fuels exhibited wide performance differences, reflected in broad emission ranges and noticeable variation in thermal efficiency. To support predictive evaluation, statistical models were established that link key fuel characteristics with CO, NOx, PM and efficiency, enabling quantitative estimation of combustion performance across heterogeneous feedstocks. To clarify ash-related effects, ten representative ashes were characterized using ICP-OES and XRD. Their chemical and phase compositions were assigned to the main Vassilev classes, which corresponded to distinct ash-forming mineral groups. Ca-rich ashes were dominated by carbonate and phosphate phases suitable for neutralization or construction applications. K-rich ashes contained soluble sulphate and chloride species relevant for nutrient-recovery routes, while Si-rich ashes consisted mainly of quartz or amorphous matrices with low reactivity. The combined combustion and ash elemental and phase analysis results demonstrate clear links between LQB composition, emission behaviour and ash transformation mechanisms, providing a practical basis for evaluating the suitability of alternative biomass pellets for small-scale heat production.
This study explores how exposure conditions affect the carbonation process of cementitious materials that include incinerated sewage sludge ash (ISSA), to evaluate ISSA's potential as a sustainable additive in cement-based construction materials and its role in CO2 sequestration. Hardened cement pastes with different amounts of ISSA (0 %, 20 %, 25 %, 30 %, and 35 %) were subjected to two carbonation experiments: indoor and outdoor in a natural environment. The carbonation process was tracked using phenolphthalein tests, scanning electron microscopy (SEM-EDS), X-ray diffraction (XRD), and calcium carbonate content measurement. Results show that ISSA-modified cement pastes have increased carbonation potential, especially at 20-25 % ISSA, with a rise in CaCO3 formation and diverse calcite morphologies. However, higher ISSA levels (>30 %) led to decreased carbonation efficiency. The outdoor experiment revealed the significant influence of temperature and humidity changes on carbonation rates, resulting in slower CO2 absorption compared to laboratory conditions.
The distribution of products formed during biomass pyrolysis depends strongly on the physical and chemical properties of the feedstock, yet quantitative comparisons across studies remain limited. This work compiles experimental and modelling data from literature to examine how five commonly reported biomass characteristics (moisture content, lignin content, ash content, higher heating value, and particle size) influence bio-oil yield. Pairwise trends highlight substantial variability in the explanatory strength of these parameters, with higher heating value showing the most consistent positive association with yield. A multivariate regression approach was then applied to assess the combined effects of all variables within a single analytical framework. The resulting model identifies higher heating value as the most informative predictor across the heterogeneous dataset, while the influence of other parameters is more dependent on interactions and covariation among biomass properties. Predicted yields for locally analysed biomass samples align with general tendencies reported in the literature, though these estimates remain provisional due to the limited size and heterogeneity of the compiled data. The study provides an integrative perspective on feedstock quality factors relevant to bio-oil production and underscores the need for experimental validation and expanded datasets to support more robust predictive modelling.
The issue of climate change has become a global concern, prompting extensive research across various disciplines, including government science. This study presents a bibliometric analysis of role of public institutions in climate change research, examining trends in publication, influential authors, leading institutions, and critical themes within this field. CiteSpace and Biblioshiny were used to analyse 1436 publications published between 2005 and 2025 using the Scopus database. The results indicate an increasing trend in publications over the last decade, highlighting the growing interest in integrating climate change mitigation and adaptation strategies within public policy and governance frameworks. Key themes identified include environmental policy, adaptive management, and sustainable development, with the United States, China, and Australia emerging as the most active countries in this research area. This study provides a comprehensive overview of the current research landscape and identifies future research directions for strengthening the role of public institutions in addressing climate change challenges, especially for the local government.
Scientists state that in recent years, the level of soil contamination worldwide has significantly increased, due to atmospheric deposits, floods, agricultural, industrial activities, and mining. Soil contamination is a widespread issue that negatively impacts the functions and processes of soil microorganisms. Heavy metals are significant factors of soil pollution, posing a threat to ecosystem functions due to their toxicity, persistence, and ability to bioaccumulate. The soil hosts diverse communities of microorganisms with specific metabolic capacities. Some microorganisms contribute to the decomposition of organic matter by interacting with toxic metals, while others participate in the formation of natural nanoparticles, thereby reducing the toxicity of heavy metals. Microorganisms can be used to immobilize heavy metals, but their effectiveness depends on various parameters such as soil type, chemical composition, pH, temperature, and moisture. Although microorganisms can be used in bioremediation, their activity is influenced by soil parameters. Understanding microorganisms‘ properties and operational parameters is essential for their successful application in soil bioremediation processes. To support further experimental studies, the Visual MINTEQ computer program was applied as a modelling tool to evaluate the behaviour and distribution of cadmium, lead, and copper in soil under different environmental conditions such as pH and temperature. These simulations do not replace microbial research but provide essential baseline information, helping to identify potentially hazardous soil conditions and to design more effective experiments on microorganisms in bioremediation could become one of the main solutions for combating soil contamination and achieving environmental sustainability.
This study applies a Social Life Cycle Assessment (S-LCA) to evaluate the social impacts of Furcellaria lumbricalis red macroalgae production through wild harvesting (WH) and offshore cultivation (OC) in the Baltic Sea Region. As macroalgae gain interest in food, feed, and biorefinery applications, understanding the social sustainability of different production systems becomes increasingly important. The assessment follows UNEP/SETAC (2020) guidelines and the ISO 14075:2024 framework, adopting a cradle-to-gate system boundary. The Social Hotspot Database (SHDB) was used to assess 30 social indicators under two scenarios: (1) WH, the predominant method in Estonia, and (2) a hypothetical OC system. The functional unit was defined as 1 USD generated over an 8-hour working day, and Monte Carlo simulations were conducted to address uncertainty. Results show that WH presents lower social risks (432.85 Pt) than OC (719.51 Pt). In WH, the main risks were linked to occupational hazards and potential forced labour during harvesting activities. In OC, boat maintenance contributed the highest share of impacts due to extended operational requirements. Key risks across both scenarios included injuries and fatalities, forced labour, and discrimination. The findings suggest that WH is the more socially sustainable option, supporting traditional employment and local communities. However, improvements in occupational health and safety remain necessary. OC, despite its potential scalability, poses higher social risks that call for strengthened labour standards and governance. Future research should incorporate site-specific data and stakeholder engagement to enhance the robustness and relevance of S-LCA in macroalgae value chains.
This paper presents a literature based comparative analysis of the heat transfer performance of heat exchanger systems operating with nanofluids. The study synthesizes and compares the results reported in published experimental and numerical works for different types of heat exchangers: shell and tube and plate heat exchangers. The comparison is based on key parameters including exergy efficiency eta ex, overall heat transfer coefficient U, and effectiveness epsilon. The results are presented as functions of the Reynolds number for laminar, transitional, and turbulent flow regimes, and for different types of nanofluids, including both mono and hybrid suspensions. The analysis shows that WC/DI nanofluids provide the highest overall heat transfer coefficient in plate heat exchangers with U = 1110 W/(m2K) at Re = 525, while 0.1 % Graphene/DI nanofluids achieve the best thermal performance in shell and tube heat exchangers exceeding U values of 0.4 % Fe3O4/DI:EG and 0.4 % ND/DI:EG by 85 W/(m2K) at Re = 3000. For plate heat exchangers 0.4 % ND/DI nanofluid demonstrate the highest effectiveness with epsilon equals to 62 % at Re = 570, whereas in shell and tube designs the best performance is obtained for 0.1 % GNP nanofluid with effectiveness reaching approximately 97.5 % at Re = 500. Furthermore, the Cu:ZnO/DI hybrid nanofluid achieved the highest exergy efficiency 66 % while other hybrid nanofluids exhibits exergy efficiencies lower by 31-34 % at a comparable Reynolds number. The results confirm the significant influence of nanofluid composition and Reynolds number in optimizing heat transfer efficiency.
Ports are essential to global trade, yet their high volume of ship traffic significantly contributes to greenhouse gas emissions, necessitating urgent strategies for climate neutrality. This study focuses on medium-sized ports where climate neutrality has not yet become a priority and explores how they can achieve this through a systems thinking approach and sustainable development practices, referencing leading ports like Rotterdam and Hamburg. Using a combination of systems thinking, comparative case studies, and qualitative analysis, the study examines various decarbonization scenarios for port infrastructure. Causal loop diagrams (CLDs) are utilized to map the interactions among environmental, economic, and operational factors affecting port sustainability. Three scenarios - baseline, moderate transition, and ambitious transition - are developed and evaluated based on greenhouse gas emissions reduction, energy efficiency, infrastructure investment, alignment with the United Nations' Sustainable Development Goals (UN SDG), and resilience enhancement. The findings demonstrate that port operations are influenced by reinforcing and balancing feedback loops, where economic growth and customer satisfaction may face challenges from regulatory pressures and climate-related operational costs. The study highlights essential areas for improvement in achieving climate neutrality in medium-sized ports. Key decarbonization techniques identified include electrification, alternative fuels, renewable energy integration, and enhancements to existing infrastructure like automated mooring systems and onshore power supply. Ultimately, the research provides insights into developing a decarbonization strategy for small and medium-sized ports, fostering sustainable development aligned with the UN SDGs and the European Green Deal.
This paper examines the dynamic relationship between electricity consumption (ELE), foreign direct investment (FDI), and carbon dioxide (CO2) emissions in 88 developing countries from 1985 to 2024. While electricity demand is widely recognized as a primary driver of CO2 emissions, the moderating role of FDI remains contested, oscillating between the “Pollution Haven” and “Pollution Halo” hypotheses. Employing the Difference Generalized Method of Moments estimation and Granger causality tests, this study provides empirical evidence of three critical patterns. First, electricity consumption exerts a significantly positive effect on CO2 emissions, reflecting the persistent reliance on fossil fuels in the energy mix. Second, FDI mitigates CO2 emissions, consistent with the “Pollution Halo” hypothesis. Third, the positive moderating effect of FDI in the ELE-CO2 nexus shows an interesting inference. The FDI targets energy-intensive sectors, creates scale effects to offset efficiency gains (mitigating CO2 emissions), and leads to expanding CO2 emissions. These results highlight integrated policy design. Decarbonizing electricity systems and strategically regulating FDI toward low-carbon sectors offer developing countries a coherent pathway to establish economic sustainability.
This paper explores sustainable integration solutions for biomethane production and injection into Latvia’s natural gas network, addressing the increasing importance of renewable energy in achieving energy independence and climate neutrality. The research investigates Latvia’s biomethane potential, current infrastructure limitations, and feasible integration pathways, drawing comparisons with leading European practices. A multicriteria methodology combining technical, environmental, and economic analyses is employed to evaluate biogas upgrading technologies, grid connection strategies, and regional implementation scenarios. The study identifies membrane separation as a highly efficient biogas upgrading method and highlights centralized biomethane injection points as an optimal integration model, particularly suited for Latvia’s geographically dispersed biogas production sites. Results suggest that biomethane could replace up to 50 % of Latvia’s current natural gas consumption, provided that adequate policy support and infrastructure investment are in place. The study concludes with recommendations to strengthen regulatory frameworks, modernize gas infrastructure, and promote regional cooperation to support a scalable and sustainable transition to biomethane. These findings offer a strategic roadmap for Latvia’s energy sector, aligned with the European Green Deal and national climate targets.
The sustainable valorization of marine biomass is central to advancing a circular bioeconomy. This study delivers the first integrated Life Cycle Sustainability Assessment (LCSA) of a cascade biorefinery for the red macroalga Furcellaria lumbricalis, evaluating environmental, economic, and, crucially, social impacts. Addressing the limited attention to social dimensions in macroalgae research, a Social Life Cycle Assessment (S-LCA) was performed using the Reference Scale Approach aligned with ISO 14075:2024 and UNEP guidelines. Stakeholder and expert evaluations were applied to two process phases: harvesting and processing. The S-LCA identified notable social benefits, including strengthened local economic development and improved worker social security, alongside moderate risks in occupational health and safety, as well as wealth distribution. These results were integrated with environmental and economic indicators using a multicriteria decision-making method (TOPSIS), comparing the cascade biorefinery (PrAp) with two alternatives: a single-product system (AAp1) and a three-line extraction system (AAp2). The cascade configuration emerged as the most sustainable option, achieving the highest closeness coefficient (0.776) and demonstrating advantages in product recovery, economic performance, and social co-benefits. Sensitivity analyses confirmed the stability of these rankings under varied weighting assumptions. Overall, this research highlights the value of multi-product valorization strategies and provides new insights to guide sustainable blue bioeconomy development, especially regarding underexplored social aspects.
According to the waste hierarchy, waste recovery is prioritized over landfilling. However, in Georgia, over 90 % of waste is landfilled, causing social, economic, and environmental issues. To ensure sustainable waste management, Waste-to-Energy should complement recycling and reuse efforts. The amount of municipal waste disposed of in landfills has significantly increased. The National Statistics Office of Georgia reports that landfill waste rose from 774.4 thousand tons in 2015 to 1184 thousand tons in 2024. The calorific value of municipal waste in Georgia is crucial for energy recovery. For efficient energy use, waste should have a minimum lower calorific value of 7 MJ/kg. Plastic, paper, and textiles have the highest calorific values. Notably, municipal waste in Georgia contains 13-14 % plastic, 10-11 % paper and cardboard, and over 4 % textiles. However, these materials are essential for recycling, which conserves natural resources and should remain a priority. This paper aims to examine the possibilities for implementing Waste-to-Energy approaches at the municipal level in Georgia. It should be noted that the composition of municipal waste has not been sufficiently studied. The existence of such data is essential for assessing the potential for Waste-to-Energy systems, as well as for improving the effectiveness of planning and implementing municipal waste management. At present, Georgia also faces a lack of experience and technical expertise needed for the introduction of Waste-to-Energy approaches.
Considering Europe's green agenda and established climate goals, discussions often center around energy efficiency and the responsible use of energy. Building renovation is recognized as a crucial step towards achieving these objectives. While most renovation discussions focus on residential buildings, the non-residential sector is frequently overlooked. In Riga, non-residential properties account for 25 % of the heat demand in buildings connected to the district heating system. This brings forth the concern that the contribution of non-residential buildings to reduce heat demand and the necessity for renovation is not adequately evaluated. This research utilizes available statistical data and system dynamics modelling to address this issue. The results show that the total annual heat demand may decrease by 27 %, while the alternative heating may be increasing by 5 % in 2050 relative to 2023. Using the currently available financial funds, renovating up to 89 % of municipal buildings and 91 % of educational institutions in state facilities is possible.
This study evaluates the environmental and economic performance of alternative reconversion strategies for drained peatlands following industrial extraction, using a real case study from Latvia. In alignment with the EU Nature Restoration Law, three main restoration pathways were analysed (i.e., renaturalization, afforestation, and blueberry cultivation), each modelled through a 100-year Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) framework. The LCA focused on greenhouse-gas (GHG) emissions, while the economic assessment included implementation costs, revenues, and the monetary value of ecosystem services. Results show that maintaining drained peatlands is the most unsustainable option (756.65 t CO2 eq ha(-)(1)). Renaturalization and blueberry cultivation reduce emissions by 225.49 t CO2 eq ha(-)(1) and 258.45 t CO2 eq ha(-)(1), respectively, whereas afforestation demonstrates the highest mitigation potential, achieving carbon neutrality after 67 years and a net GHG uptake of 310.09 t CO2 eq ha(-)(1) by year 100. Integrating renewable-energy systems further enhances performance, with afforestation combined with solar or wind installations yielding additional avoided emissions exceeding 500 t CO2 eq ha(-)(1). Economically, blueberry cultivation provides the largest direct revenues, while afforestation yields the highest carbon-credit value. However, when ecosystem services are monetized, renaturalization becomes the most beneficial strategy, reaching a cumulative value of 31.2 million ha(-)(1). Overall, the study highlights that combining LCA and LCC provides robust decision support for sustainable peatland management, demonstrating that rewetting and afforestation can effectively balance climate-mitigation goals with socio-economic viability. Furthermore, the economic outcomes are strongly influenced by the ecosystem-service monetisation methodology used; the assumptions and limitations of this approach are now fully clarified in the Methods and discussed as a source of uncertainty. Given the limited availability of long-term field data, the analysis is based on deterministic scenarios without explicit uncertainty ranges, variability estimates, or sensitivity analyses. Likewise, N2O fluxes could not be included due to the lack of robust, site-specific emission factors for restored peatlands.
The geometric form of a building strongly influences its material use, heat losses, and energy efficiency. This paper presents an analytical optimization of L-shaped residential buildings aimed at minimizing the external surface area for a prescribed volume. Both symmetric and asymmetric configurations are examined under realistic design constraints, including fixed or bounded wing aspect ratios and fixed building height. Using explicit optimization methods and Karush-Kuhn-Tucker conditions, closed-form expressions for the optimal geometric parameters and minimal envelope area are derived. The results show that unconstrained optimization leads to degenerate cuboid shapes, highlighting the importance of geometric constraints to preserve the L-shaped form. The obtained results provide practical design guidelines for architects and engineers, supporting informed early stage decisions that balance functional requirements, regulatory constraints, architectural intent, and energy performance. Case studies of existing houses demonstrate that the proposed approach can reduce external surface area or confirm near-optimality of practical designs, supporting energy-efficient early-stage architectural decisions.
