Search Results (60)

Urban leaf litter represents an underutilized biomass resource with potential applications in sustainable building materials. This study investigates the suitability of dried, comminuted leaves collected from municipal green areas as a loose-fill thermal insulation material. The material was characterized in terms of thermal conductivity, settlement behavior, fire reaction, resistance to mold growth, water vapor diffusion, hygroscopic sorption, and short-term water absorption. Tests were conducted following relevant DIN and ISO standards, with both untreated and flame-retardant-treated samples examined. Results indicate that the thermal conductivity of leaf-based insulation (λ = 0.041–0.046 W/m·K) is comparable to other bio-based loose-fill materials such as cellulose and wood fiber. Optimal performance was achieved for particles sized 2–16 mm, showing settlement below 1%. All variants, including untreated material, fulfilled the fire resistance requirements of class E, while selected treatments further improved fire resistance. The material exhibited moderate vapor permeability (μ ≈ 4–5), low water absorption, and moisture buffering behavior similar to that of other bio-based insulation materials. Resistance to mold growth was satisfactory under standardized conditions. Overall, the results demonstrate that leaf litter can serve as an effective and environmentally favorable loose-fill insulation material, offering an innovative recycling pathway for urban green waste. Full article

Wildfires are increasingly recognized as a climatological hazard, able to threaten industrial and critical infrastructure safety and operations and lead to Natech disasters. Future projections of exacerbated fire regimes increase the likelihood of Natech disasters, therefore increasing expected direct damage costs, clean-up costs, and long-term economic losses due to business interruption and environmental remediation. While large industrial complexes, such as oil, gas, and chemical facilities have sufficient resources for the implementation of effective prevention and mitigation plans, small-to-medium-sized industrial hubs are particularly vulnerable due to their scattered distribution and limited resources for investing in comprehensive fire prevention systems. This study targets the vulnerability of these communities by proposing the deployment of Wireless Sensor Networks (WSNs) as cost-effective Early Wildfire Detection Systems (EWDSs) to safeguard wildland and industrial domains. The proposed approach leverages wildland–industrial interface (WII) geospatial data, simulated wildfire dynamics data, and mathematical optimization to maximize detection efficiency at minimal cost. The WII delimits the boundary where the presence of wildland fires impacts industrial activity, thus representing a proxy for potential Natech disasters. The methodology is tested in Cocentaina, Spain, a municipality characterized by a highly flammable Mediterranean landscape and medium-scale industrial parks. Results reveal the complex trade-offs between detection characteristics and the degree of protection in the combined wildland and WII areas, enabling stakeholders to make informed decisions. This methodology is easily replicable for any municipality and industrial installation, or for generic wildland–human interface (WHI) scenarios, provided there is access to wildfire dynamics data and geospatial boundaries delimiting the areas to protect. Full article

This case study evaluates the economic and energy efficiency of retrofitting a hospital heating system in Krakow, Poland, by transitioning from a district-heating-only model to a bivalent hybrid system. The analyzed configuration integrates air-to-water heat pumps (HP), a 180 kWp photovoltaic (PV) installation, and a 120 kWh battery energy storage (ES) unit, while retaining the municipal district heating network as a peak load and backup source. Utilizing high-resolution quasi-steady-state simulations in Ebsilon Professional (10 min time step) and projected 2025 market data, the study compares three modernization scenarios differing in heat pump capacity (20, 40, and 60 kW). The assessment focuses on key performance indicators, including Net Present Value (NPV), Levelized Cost of Heating (LCOH), and Simple Payback Time (SPBT). The results identify the bivalent system with 40 kW thermal capacity (Variant 2) as the economic optimum, delivering the highest NPV (EUR 121,021), the lowest LCOH (0.0908 EUR/kWh), and a payback period of 11.94 years. Furthermore, the study quantitatively demonstrates the law of diminishing returns in the oversized scenario (60 kW), confirming that optimal sizing is critical for maximizing the efficiency of bivalent systems in public healthcare facilities. This work provides a detailed methodology and data that can form a basis for making investment decisions in similar public utility buildings in Central and Eastern Europe. Full article

A large number of state-owned companies were privatized in the Czech Republic after the end of the communist regime, mostly through their transformation into joint-stock companies. The water management sector was no exception from this process. The ownership of infrastructure networks was transferred to individual municipalities, which are legally obliged to provide their inhabitants with water supply and sewerage disposal. Subsequently, the municipalities joined together in joint-stock companies to enhance their capacity to provide sufficient financial resources for the rehabilitation and development of water infrastructure and also to enable the implementation of sustainable water management strategies, which are key to environmental protection. Assets contributed to joint-stock companies in the form of non-monetary contributions serve as a basis for a proportionate allocation of shares, representing the shareholder’s share of participation in the company’s management. An analysis of the asset performance within these companies indicates the necessity of developing an optimized methodology for determining the number of shares allocated for such non-monetary contributions. This need arises from significant disparities in both profitability and cost-efficiency among municipalities, depending on factors such as population size (revenues) and the length and technical characteristics of the infrastructure networks (costs) contributed to the joint-stock companies. The authors of the article present the research project results, aimed at developing a methodological procedure for determining the price (value) of municipal infrastructure assets contributed as non-monetary capital to a joint-stock company that owns and operates water management networks, from which the secondary objective of determining the fair value of a municipality’s water management infrastructure assets based on the developed methodology is derived. The proposed methodological procedure is primarily based on establishing the ratio between the fixed and variable costs of the municipality. Full article

As critical national energy arteries, long-distance large-scale cross-regional gas transmission networks are characterized by high operating pressures, extensive spatial coverage, and complex topological structures. Thus, the multi-hazard profiles threatening its safety and reliability operation differ significantly from those of local urban gas distribution networks. This research develops a resilience assessment framework capable of quantifying resistance, adaptation, and recovery capacities of such energy systems. The framework establishes performance indicator systems based on design parameters, installation environments, and construction methods for long-distance trunk pipelines and key facilities such as storage facilities. Furthermore, based on complex network theory, the size of the largest connected component and global efficiency of the transmission network are selected as core topological metrics to characterize functional scale retention and transmission efficiency under disturbances, respectively, with corresponding quantification methods proposed. A cross-regional pipeline transmission network within a representative municipal-level administrative region in China is used as a case for empirical analysis. The quantitative assessment results of pipeline and network resilience are analyzed. The research indicates that trunk pipeline resilience is significantly affected by characteristic parameters, the laying environment, and installation methods. It is notably observed that installation methods like jacking and directional drilling, used for road or river crossings, offer greater resistance than direct burial but considerably lower restoration capacity due to the complexity of both the environment and the repair processes, which increases time and cost. Moreover, simulation-based comparison of recovery strategies demonstrates that, in this case, a repair-time-prioritized strategy more effectively enhances overall adaptive capacity and restoration efficiency than a node-degree-prioritized strategy. The findings provide quantitative analytical tools and decision-support references for resilience assessment and optimization of cross-regional energy transmission networks. Full article

Pyrolysis, as an efficient thermochemical conversion technology, demonstrates substantial advantages in achieving reduction and resource recovery of landfill sludge (LS). This work systematically examined the effects of pyrolysis temperature, residence time, and sludge type on the yield and compositional transformation of pyrolysis gases, as well as the yield and structural characteristics of the derived biochar, using LS and four other types of sludge as subjects. The research results indicate that as the pyrolysis temperature increased from 300 to 900 °C, the total gas yield of the LS sample rose markedly from 11.0 to 139.8 L/kg. The biochar obtained at 600 °C possessed the highest specific surface area (26.327 m²/g), with pore sizes primarily concentrated in the range of 10–20 nm. Extending the residence time facilitated the continuous release of gaseous products but exerted minimal influence on the yield of the solid-phase products. The pyrolysis responses varied considerably among different sludge types. Municipal sludge (MS) exhibited the highest gas production yield (197.5 L/kg), whereas LS demonstrated a greater carbon retention rate (73.7%). This work, based on a systematic analysis of product conversion behaviors, elucidated the correlation mechanism between parameter regulation and product performance during the pyrolysis process, thereby offering theoretical foundations and data support for optimizing LS pyrolysis conditions and enhancing product utilization efficiency. Full article

While community energy initiatives and pilot projects have demonstrated technical feasibility and economic benefits, their site-specific nature limits transferability to systematic, scalable investment models. This study addresses this gap by proposing a modular framework for Renewable Energy Valleys (REVs), developed from real-world Community Energy Lab (CEL) demonstrations in Crete, Greece, which is an island with pronounced seasonal demand fluctuation, strong renewable potential, and ongoing hydrogen valley initiatives. Four modular business schemes are defined, each representing different sectoral contexts by combining a baseline of 50 residential units with one representative large consumer (hotel, rural households with thermal loads, municipal swimming pool, or hydrogen bus). For each scheme, a mixed-integer linear programming model is applied to optimally size and operate integrated solar PV, wind, battery (BAT) energy storage, and hydrogen systems across three renewable energy penetration (REP) targets: 90%, 95%, and 99.9%. The framework incorporates stochastic demand modeling, sector coupling, and hierarchical dispatch schemes. Results highlight optimal technology configurations that minimize dependency on external sources and curtailment while enhancing reliability and sustainability under Mediterranean conditions. Results demonstrate significant variation in optimal configurations across sectors and targets, with PV capacity ranging from 217 kW to 2840 kW, battery storage from 624 kWh to 2822 kWh, and hydrogen systems scaling from 65.2 kg to 192 kg storage capacity. The modular design of the framework enables replication beyond the specific context of Crete, supporting the scalable development of Renewable Energy Valleys that can adapt to diverse sectoral mixes and regional conditions. Full article

The aging of the Portuguese population is a multifaceted challenge that requires a coordinated and comprehensive response from society. In this context, social service institutions play a fundamental role in providing aid and support to the elderly, ensuring that they can enjoy a dignified and fulfilling life even in the face of the challenges of aging. This research proposes a Balanced Multiple Traveling Salesman Problem based on the Ant Colony Optimization algorithm (ACO-BmTSP) to solve a distribution of meals problem in the municipality of Mogadouro, Portugal. The Multiple Traveling Salesman Problem (mTSP) is an NP-complete problem where m salesmen perform a shortest tour between different cities, visiting each only once. The primary purpose is to minimize the sum of all distance traveled by all salesmen keeping the tours balanced. This paper shows the results of computing obtained for three, four, and five agents with this new approach and their comparison with other approaches like the standard Particle Swarm Optimization and Ant Colony Optimization algorithms. As can be seen, the ACO-BmTSP, in addition to obtaining much more equitable paths, also achieves better results in lower total costs. In conclusion, some benchmark problems were used to evaluate the efficiency of ACO-BmTSP, and the results clearly indicate that this algorithm represents a strong alternative to be considered when the problem size involves fewer than one hundred locations. Full article

Urban development is the planned growth of cities that takes into account ecological issues, the needs of urban life, social and technical equipment standards, and quality of life. However, as a result of policies implemented by decision-makers and users, both planned and unplanned, urban space is expanding spatially outwards from the city, while also experiencing densification in vacant areas within the city and functional transformations in land use. This process, known as urban sprawl, has been intensely debated over the past century. Making the negative effects of urban sprawl measurable and understandable from a scientific perspective is critically important for sustainable urban planning and management. Transportation surfaces hold a significant share in the land use patterns of expanding cities in physical space, and accessibility is one of the main driving forces behind land use change. Therefore, the most significant consequence of urban sprawl is the increase in urban mobility, which is shaped by the needs of urban residents to access urban functions. This increase poses risk factors for the planning period in terms of time, cost, and especially environmental impact. Urban space has a dynamic and complex structure. Planning is based on being able to guess how this structure will change over time. At first, geometric models were used to study cities, but as time went on and the network of relationships became more complicated, more modern and technological methods were needed. Artificial Neural Networks, Support Vector Machines, Agent-Based Models, Markov Chain Models, and Cellular Automata, developed using computer-aided design technologies, can be cited as examples of these approaches. In this study, the temporal change in urban sprawl and its relationship with influencing factors will be revealed using the SLEUTH model, which is one of the cellular automata-based urban simulation models. Erzurum, one of the medium-sized metropolitan cities that gained importance after the conversion of provincial borders into municipal borders with the Metropolitan Law No. 6360, has been selected as the case study area for this research. The urban sprawl process and determining factors of Erzurum will be analyzed using the SLEUTH model. By creating a simulation model of the current situation within the specified time periods and generating future scenarios, the aim is to develop planning decisions with sustainable, ecological, and optimal size and density values. Full article

The integrity of urban water supply pipelines, an essential element of municipal infrastructure, is frequently undermined by internal defects such as corrosion, tuberculation, and foreign matter. Traditional inspection methods relying on CCTV are time-consuming, labor-intensive, and prone to subjective interpretation, which hinders the timely and accurate assessment of pipeline conditions. This study proposes YOLOv8-VSW, a systematically optimized and lightweight model based on YOLOv8 for automated defect detection in in-service pipelines. The framework is twofold: First, to overcome data limitations, a specialized defect dataset was constructed and augmented using photometric transformation, affine transformation, and noise injection. Second, the model architecture was improved on three levels: a VanillaNet backbone was adopted for lightweighting, a C2f-Star module was introduced to enhance multi-scale feature fusion, and the WIoUv3 dynamic loss function was employed to improve robustness under complex imaging conditions. Experimental results demonstrate the superior performance of the proposed YOLOv8-VSW model. This study validates the framework on a curated, real-world image dataset, where YOLOv8-VSW achieved mAP@50 of 83.5%, a 4.0% improvement over the baseline. Concurrently, GFLOPs were reduced by approximately 38.9%, while the inference speed was increased to 603.8 FPS. The findings validate the effectiveness of the proposed method, delivering a solution that effectively balances detection accuracy, computational efficiency, and model size. The results establish a strong technical basis for the intelligent and automated control of safety in urban water supply systems. Full article

Porous carbon from renewable resources like biomass is a key material utilized in many applications ranging from environmental remediation to energy storage. There are limited reports in the literature on the effects of biomass pretreatment, production process parameters, and downstream processing on the final product properties. This is the first study aimed at closing the latter research gap. Six different types of underutilized biomass were examined: eastern red cedar wood, pecan shells, hazelnut shells, algal biomass, miscanthus, and sludge produced at municipal wastewater treatment facilities. Although pretreatment of biomass with KOH or ZnCl₂ enhanced formation of micro- and mesopores, carbon yield was lower (15.3–32.5%) than that obtained via non-catalytic pyrolysis (28.3–48%). An optimization study performed using response surface methodology and cedar wood has shown the significant effects (p < 0.05) of temperature and catalyst/biomass ratio on total BET pore volume and surface area. Additionally, catalyst/biomass ratio had a significant effect on the crystal structure and pore size distribution in the carbon produced by pyrolysis. Hence, optimization of process temperature, hold time, and activation ratio is capable of yielding porous carbon from cedar wood pyrolysis with desirable properties. Full article

Mechanical–biological treatment plants face challenges in effectively separating organic fractions from residual municipal solid waste for biological treatment. This study investigates the optimization measures carried out at the Erbenschwang MBT facility, which transitioned from solely aerobic treatment to integrated anaerobic digestion using a screw press. This study focused on evaluating the efficiency of each mechanical pretreatment step by investigating the composition of the residual waste, organic fraction recovery rate, and screw press performance in recovering organic material and biogas to press water. The results showed that 92% of the organic material from the residual waste was recovered into fine fractions after shredding and trommel screening. The pressing experiments produced high-quality press water with less than 3% inert material (0.063–4 mm size). Mass balance analysis revealed that 47% of the input fresh mass was separated into press water, corresponding to 24% of the volatile solids recovered. Biogas yield tests showed that the press water had a biogas potential of 416 m³/ton VS, recovering 38% of the total biogas potential. In simple terms, the screw press produced 32 m³ of biogas per ton of mechanically separated fine fractions and 20 m³ per ton of input residual waste. This low-pressure, single-step screw press efficiently and cost-effectively prepares anaerobic digestion feedstock, making it a promising optimization for both existing and new facilities. The operational configuration of the screw press remains an underexplored area in current research. Therefore, further studies are needed to systematically evaluate key parameters such as screw press pressure (bar), liquid-to-waste (L/ton), and feed rate (ton/h). Full article

This study presented an investigation into the role of ceramsite pore structures in optimizing DNBFs for nitrate-contaminated water treatment. Through systematic comparison of three ceramsite media (CE1, CE2, CE3) with distinct pore structures, we elucidated the microbial mechanisms underlying nitrate removal efficiency by analyzing denitrification performance, biomass accumulation, EPS, microbial community structure, and nitrogen metabolic function. Results demonstrated that the CE2 medium, characterized by an effective porosity (pore size > 0.5 μm) of 55.8% and an optimal porosity (pore size 0.5–25 μm) percentage of 83.1%, achieved superior nitrate removal efficiency (87.8%) with an R_vd of 0.82 kg TN/(m³·d) at HRT = 1.5 h, outperforming CE1 (0.74 kg TN/(m³·d)) and CE3 (0.68 kg TN/(m³·d)). Enhanced performance was mechanistically linked to CE2’s higher biomass accumulation (8.5 vs. 7.8 mg/m² in CE1 and 6.9 mg/m² in CE3) and greater EPS production (48.5 vs. 44.7 in CE1 and 35.4 mg/g in CE3), which facilitated biofilm resilience under hydraulic stress. Microbial analysis revealed CE2’s unique enrichment of a higher relative abundance of Proteobacteria (90.1% vs. 67.2% in CE1 and 47.4% in CE3) and denitrifying taxa (unclassified_f_Comamonadaceae: 42.7%, unclassified_f_Enterobacteriaceae: 35.3%). PICRUST2 showed 1.2- and 1.4-fold higher abundance of denitrification genes (narGHI, nosZ) compared to CE1 and CE3, respectively. These findings establish that optimizing ceramsite pore structure, particularly increasing the optimal porosity ratio (pore size 0.5–25 μm) can enhance denitrification efficiency, offering a scalable strategy for cost-effective groundwater remediation. This work provides actionable criteria for designing high-performance DNBFs, with immediate relevance to industrial and municipal wastewater treatment systems facing stringent nitrate discharge limits. Full article

This article analyzes population movement patterns in the Vysočina Region, Czechia, using mobile network geolocation data. Geolocation data provide new insights into population movement and structure, capturing real-time fluctuations in population size at different times of day and days of the week. The article aims to contribute to a better understanding of spatiotemporal population dynamics and identify links between movement patterns and different types of areas. Key mobility trends, such as work commuting, seasonal migration related to second homes and tourism, and the influence of urbanization on movement patterns, are identified. A scaling approach for categorizing municipalities based on their characteristics is proposed and tested in a case study of Vysočina Region municipalities. Furthermore, a case study of various municipality types demonstrates the practical application of geolocation data in spatial planning. The results highlight the value of these data for spatial planning, enabling a better understanding of population needs and optimization of public services and infrastructure. Full article

Driven by the path of ecological transition, municipal solid waste management is now more than ever at the center of debates on the most efficient delivery methods. Although competition policy advocates subdivision into lots to facilitate medium-sized enterprise participation, in some cases—notably when substantial investments are required to achieve circular economy and sustainable development goals—a single-operator model may prove more efficient. Using a mixed research approach that integrates empirical evidence and market analysis, this study examines the relevance of cost curves, transaction costs, and market structure in determining the optimal service delivery model. The findings indicate that for large cities, consolidating MSW management services under a single contract yields significant cost advantages due to economies of scale and scope and is better suited to supporting the investments necessary for circular economy objectives. Practical implications for local policymakers highlight the need to assess utility sector policies carefully. Decisions at the local level should account for the interplay between the economic environment and the role of industrialization and economies of scale in fostering sustainable development. We suggest policymakers design policies that balance market efficiency with equitable access to services while also considering the scale of service provision, as it influences sustainability and economic resilience. Full article