Search Results (195)

This study addresses the use of porcelain polishing waste as a pyro-expansive agent in clay-based formulations for the production of lightweight aggregates, aiming to reduce the consumption of natural resources and mitigate environmental impacts. In line with circular economy principles and sustainable construction goals, this study investigates the potential use of porcelain polishing waste as a pyro-expansive agent in clay-based formulations for producing sustainable lightweight aggregates. Using the Taguchi method and ANOVA, the effects of key processing parameters were evaluated. The results demonstrated a broad range of volumetric changes, from shrinkage of 40.84% to expansion of 91.69%, depending on the formulation and processing conditions. The aggregates exhibited specific mass values ranging from 0.99 g/cm³ to 2.36 g/cm³, water absorption up to 3.29%, and mechanical strength from 4.57 MPa to 39.87 MPa. Notably, nine of the sixteen experimental conditions met the technical standards for classification as LWA, indicating suitability for applications in high-strength, structural, and non-structural lightweight concretes, as well as lightweight mortars. The performance of these materials was directly linked to the chemical and mineralogical characteristics of the precursors and the proportion of pyro-expansive waste used. Overall, the findings suggest that 50% of the produced aggregates are viable for high-performance concrete applications, offering an environmentally responsible alternative to virgin raw materials and contributing to sustainable waste valorization in the ceramic and construction industries. Full article

In Poland, renewable energy sources (RESs) are becoming increasingly significant, also in the agricultural sector. Poland has committed to EU energy policies to achieve a 21% share of RESs in gross final energy consumption until 2030. The newest data from 2023 indicates that up to that time, it was 16.56%. The situation is slightly worse in transport, where a 6% share of RESs has been achieved, compared to 14%, which is the target for 2030. The agricultural sector plays a significant role in this transition, as it offers opportunities for bioenergy production, such as biogas and biofuels, derived from agricultural waste and residues, but also by giving a place for photovoltaic panels and windmill farms. While the progress made is evident, challenges persist. This review paper presents the current status and prospects for the development of RESs with particular emphasis on the share of the agricultural sector. To do this, desk research and a literature review have been conducted. The newest statistics have been presented. A significant opportunity for the development of RESs in agriculture lies in harnessing the potential of the raw material base for biogas production, as well as leveraging funding from numerous support programs. A significant opportunity also exists for the development of agrivoltaics. Creating a legal framework for the development of agrivoltaics, as well as creating equal opportunities for all RESs to obtain funding, is a challenge. A major identified challenge that must be addressed, in order to capitalize on the potential of Polish agriculture for the development of RESs, is increasing connection capacity and expanding and modernizing the energy system. Full article

Additive manufacturing (3D printing) using Computer-Aided Design (CAD) has emerged as a cost-effective alternative to subtractive milling in restorative dentistry, offering reduced material waste and lower production costs. This study aimed to compare the physical properties, specifically water sorption, water solubility, and surface roughness, of milled and 3D-printed hybrid resin composite materials. Standardized disk-shaped samples were fabricated using a digital workflow. The additive group included 15 samples printed with a DLP printer using CROWNTEC resin at three different orientations (0°, 45°, and 90°), with five samples prepared at each printing orientation. The subtractive group consisted of specimens milled from the SHOFU DISK hybrid resin composite. Surface roughness samples were also prepared for both methods. Statistical analysis using one-way ANOVA, post hoc tests, and paired t-tests revealed significant differences among groups in all tested properties (p < 0.001). Subtractive manufacturing consistently outperformed additive techniques. Among the printed groups, orientation at 0° showed the most favorable outcomes. Moreover, polishing significantly improved surface roughness in both manufacturing methods (p < 0.001). These findings emphasize the influence of the fabrication method and printing orientation on the clinical performance of hybrid resin composites, highlighting the importance of polishing in optimizing the surface quality for 3D-printed restorations. Full article

Introduction: Digital planning and evolution of technology is allowing dentistry to be more efficient in time than before. In orthodontics the main purpose is to obtain fewer patient visits and to reduce the bonding time. For that, indirect bonding planned with CAD-CAM softwares is used to obtain a shorter treatment period, in general, and less chair-time. This waste of chair-time should also be reduced in other fields of dentistry such as endodontics, surgery, prosthodontics, and aesthetics. Methods: A total of 504 teeth were embedded into epoxy resin models mounted as a dental arch. Customized lingual multibracket appliances were bonded by a current adhesion protocol. After that, they were debonded, the polishing of cement remnants was performed with three different burs and two drills. The polishing time of each group was recorded by an iPhone 14 chronometer. Results: Descriptive and comparative statistical analyses were performed with the different study groups. Statistical differences (p < 0.005) between diamond bur and tungsten carbide and white stone burs and turbine were obtained, with the first being the slowest of them. Discussion: Enamel roughness was widely studied in orthodontics polishing protocol as the main variable for protocols establishment. However, in lingual orthodontics, due the difficulty of the access to the enamel surfaces, the protocol is not clear and efficiency should be considered. It was observed that the tungsten carbide bur is the safest bur. It was also recommended that a two-step protocol of polishing by tungsten carbide bur be followed by polishers. Conclusions: A tungsten carbide bur mounted in a turbine was the most efficient protocol for polishing after lingual bracket debonding. Full article

In the past decade, agricultural biogas plants have become one of the key tools driving the energy transition in rural areas. Nevertheless, their development in Poland still lags behind that in Western European countries, suggesting the existence of barriers that go beyond technological or regulatory issues. This study aims to examine how Polish farmers perceive the risks and expected benefits associated with investing in biogas plants and which of these perceptions influence their willingness to invest. The research was conducted in the second quarter of 2025 among farmers planning to build micro biogas plants as well as owners of existing biogas facilities. Geographic Information System (GIS) tools were also used in selecting respondents and identifying potential investment sites, helping to pinpoint areas with favorable spatial and environmental conditions. The findings show that both current and prospective biogas plant operators view complex legal requirements, social risk, and financial uncertainty as the main obstacles. However, both groups are primarily motivated by the desire for on-farm energy self-sufficiency and the environmental benefits of improved agricultural waste management. Owners of operational installations—particularly small and medium-sized ones—tend to rate all categories of risk significantly lower than prospective investors, suggesting that practical experience and knowledge-sharing can effectively alleviate perceived risks related to renewable energy investments. Full article

The aim of the current study was to determine the scale and underlying causes for the waste of raw and processed fruits and vegetables in Polish households. A survey was conducted on a representative sample of 1100 respondents. The collected empirical data were analyzed using statistical tools such as non-parametric tests, multiple regression methods, and logistic regression. This study assessed the level and determinants of waste of raw and processed fruits and vegetables, identified the reasons for this waste and their impact on its extent, and analyzed the effect of waste prevention methods (including processing) on the scale of product losses. This study showed that the scale of waste of processed fruits and vegetables in Polish consumer households is significantly lower than that of raw products. The level of waste for both raw and processed products vary depending on place of residence, education, income, household size, and, in the case of processed fruits and vegetables, also the age of respondents. The main reason for fruit and vegetable losses in households is missing the product’s expiration date. Logistic regression analysis showed that the most effective strategies for reducing the waste of raw fruits and vegetables include purchasing the right quantities and freezing them. In contrast, practices such as donating food to others or composting were linked to a statistically significant decrease in the likelihood of reducing waste. Full article

Chemically demethoxylated and Ca-cross-linked orange-peel waste was engineered as a biosorbent for Mn(II) removal from water. A three-factor Box–Behnken design (biosorbent dose 3–10 g L⁻¹, initial Mn²⁺ 100–300 mg L⁻¹, contact time 3–8 h; pH 5.5 ± 0.1, 25 °C) required only 16 runs to locate the optimum (10 g L⁻¹, 100 mg L⁻¹, 8 h), at which the material removed 94.8% ± 0.3% manganese removal under the optimized conditions (10 g L⁻¹, 100 mg L⁻¹, 8 h, pH 5.5) of dissolved manganese and reached a Langmuir capacity of 29.7 mg g⁻¹. Equilibrium data fitted the Freundlich (R² = 0.968) and Sips (R² = 0.969) models best, indicating a heterogeneous surface, whereas kinetic screening confirmed equilibrium within 6 h. FTIR and SEM–EDX verified abundant surface –COO⁻/–OH groups and showed Mn deposits that partially replaced residual Ca, supporting an ion-exchange component in the uptake mechanism. A preliminary cost analysis (<USD 10 kg⁻¹) and > 90% regeneration efficiency over three cycles highlight the economic and environmental promise of this modified agro-waste for polishing Mn-laden effluents. Full article

The processing of dimension stones for the construction sector involves transforming rock blocks into slabs via sawing and polishing. This process generates a fine-grained waste composed largely of rock powder derived from the processed rock. Several studies indicate that the rock powder produced as a processing waste can release Ca, Mg, and K. However, alongside the release of macronutrients, there is the possibility of releasing undesirable constituents, such as Na, which is also a component of the minerals forming silicate rocks. This study aimed to analyze the risk of salinization that these materials may cause to soil if applied without a thorough evaluation of their composition. Samples were analyzed in terms of physical, chemical, and mineralogical parameters; exchangeable inorganic constituents; percentage of exchangeable sodium; and sodium adsorption ratio. The data indicate that residues stored in landfills in a random and unsorted manner do not fully meet the criteria established by Brazilian regulations for soil remineralizers. However, their characteristics suggest good potential for use in the agricultural sector, although this would require blending with other agricultural inputs and/or segregating residues from certain types of rocks to comply with current regulations. Full article

The combustion of hard coal and lignite in power and combined heat and power plants generates significant amounts of coal fly ash (CFA), a waste material with variable properties. CFA naturally contains radionuclides, specifically naturally occurring radioactive materials (NORMs), which pose potential radiological risks to the environment and human health during their storage and utilization, including their incorporation into building materials. Although global research on the radionuclide content in CFA is available, there is a clear gap in detailed and current data specific to Central and Eastern Europe and notably, a lack of a systematic analysis investigating the influence of installed power plant capacity on the concentration profile of these radionuclides in the generated ash. This study aimed to fill this gap and provide crucial data for the Polish energy and environmental context. The objective was to evaluate the concentrations of selected radionuclides (²³²Th, ²²⁶Ra, and ⁴⁰K) in coal fly ash samples collected between 2020 and 2023 from 19 Polish power and combined heat and power plants with varying capacities (categorized into four groups: S1–S4) and to assess the associated radiological risk. Radionuclide concentrations were determined using gamma spectrometry, and differences between groups were analyzed using non-parametric statistical methods, including PERMANOVA. The results demonstrated that plant capacity has a statistically significant influence on the concentration profiles of thorium and potassium but not radium. Calculated radiological hazard assessment factors (Ra_eq, H_ex, H_in, IAED) revealed that although most samples fall near regulatory limits (e.g., 370 Bq kg⁻¹ for Ra_eq), some exceed these limits, particularly in groups S1 (plants with a capacity less than 300 MW) and S4 (plants with a capacity higher than 300 MW). It was also found that the frequency of exceeding the annual effective dose limits (IAEDs) showed an increasing trend with the increasing installed capacity of the facility. These findings underscore the importance of plant capacity as a key factor to consider in the radiological risk assessment associated with coal fly ash. This study’s outcomes are crucial for informing environmental risk management strategies, guiding safe waste processing practices, and shaping environmental policies within the energy sector in Central and Eastern European countries, including Poland. Full article

Brine purification is an important process unit in chlor-alkali industrial plants for the production of sodium hydroxide, chlorine, and hydrogen. The membrane cell process requires ultrapure brine, which is obtained through mechanical filtration, chemical precipitation and fine polishing, and ion exchange using polymer resins. Temperature variations can lead to the degradation of the exchange properties of these resins, primarily causing a decrease in their exchange capacity, which negatively impacts the efficiency of the brine purification. After multiple ion exchange regeneration cycles, significant quantities of spent resins may be generated. These must be managed in accordance with resource efficiency and hazardous waste management to ensure the sustainability of the industrial process. In this paper, a comparative study is conducted to characterize the long-term stability of a new commercial chelating resin used in the industrial electrolysis process. The spectroscopic methods of physicochemical characterization included: scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR). The thermal behavior of the polymer resins was evaluated using the following thermogravimetric methods: thermogravimetry (TG), derivative thermogravimetry (DTG), and differential thermal analysis (DTA), while the moisture behavior was studied using dynamic vapor sorption (DVS) analysis. To assess the energy potential, the polymer resins were analyzed to determine their calorific value and overall energy content. Full article

Over 2 million tonnes of ceramic waste are generated annually in South Africa, with the majority disposed of in landfills, contributing to environmental degradation. Meanwhile, researchers are actively seeking sustainable alternatives to Portland cement (PC), which is associated with significant environmental challenges. Ceramic waste powder (CWP) refers to finely milled ceramic waste and powder derived from the polishing and finishing stages of ceramic production. This review examines the potential of CWP as a partial replacement for PC in concrete, focusing on its effects on workability, mechanical durability, and microstructural properties. The findings indicate that moderate replacement levels (up to 20%) enhance the compressive and flexural strengths of concrete. However, these benefits are not consistently reported across all studies. Additionally, CWP improves the microstructural properties of the concrete. This is probably due to the pozzolanic reactions of CWP, which result in a denser concrete matrix and enhanced long-term durability. Notable durability benefits include reduced water absorption, increased resistance to chemical attacks, and improved thermal insulation. However, the performance of concrete with higher CWP replacement levels (above 30%) remains unclear. Some studies have reported strength reductions and increased susceptibility to durability loss at this level. Further studies should focus on clarifying its pozzolanic reactivity, durability in aggressive environments, and optimum replacement percentage. Full article

This study proposes an innovative model for animal waste utilization in the largest Polish meat utilization plant, which assumes an integrated system that processes one part of the meat waste by anaerobic digestion and the second part into meat and bone meal via the hydrothermal method. The solution is based on implementing the concept of industrial symbiosis, using a purposefully directed flow of materials, waste, and energy to create a closed recycling cycle. This study analyzes the key strategic, organizational, and technical circular economy activities that enable the transformation of waste into valuable materials and energy, thanks to the use of closed-loop materials and energy cycles. It estimates the integrated system’s investment costs and economic and environmental outcomes. The presented method allows for biogas production from the bio-fermentation of 160,000 t/y of animal waste; this would more than cover the heat requirements for obtaining 110,000 t/y of meat and bone meal using the hydrothermal method. Full article

The construction industry continues to face significant challenges related to waste on construction sites, significantly impacting cost, timelines, and the quality of project outcomes. This study aims to identify contemporary sources of construction waste, assess their variability over time using data from 2016, 2021, and 2024, and evaluate strategies for their reduction. A mixed-methods approach was adopted, combining a literature review with a survey among Polish construction contractors. A total of 34 waste factors were assessed in terms of frequency and significance. Building Information Modelling (BIM) is recommended—based on both survey results and studies in the literature—as an effective strategy to optimise construction efficiency by reducing waste and supporting sustainability objectives. The analysis also shows increasing awareness and application of Lean Principles and BIM among contractors. By 2024, BIM use increased from 8% in 2016 to 63%, indicating broader recognition, although this recognition was still insufficient given the severity of reported waste. The findings revealed design errors as the most critical source of waste, alongside execution delays, quality defects, damages to completed works, and excessive workloads. Respondents also identified additional factors, including erroneous bid assumptions, unclear investor expectations, unrealistic deadlines, equipment failures, and overdesign. These underscore the need for strategic, technology-driven waste mitigation. Full article

The high treatment costs associated with wastewater and waste solutions produced by the anodic oxidation polishing section significantly limit industry development. To address this challenge, the present study investigates the characteristics of polishing wastewater and waste solutions, employing extraction and ion exchange combined with diffusion dialysis to recover effective acids. For waste tank solutions, single and dual solvent extraction experiments were conducted to determine the optimal extraction system. Electrostatic potential and interaction region indicator (IRI) analyses were performed to provide theoretical justification. Regarding cleaning wastewater, resin adsorption was applied to selectively remove aluminium ions from waste acid solutions, facilitating effective acid recovery. Static and dynamic adsorption–desorption experiments were initially performed to identify suitable resins. Subsequently, optimised parameters—including adsorption and desorption concentrations, volumes, and flow rates—were systematically established through conditional experiments, and diffusion dialysis was applied to recover acids from the desorbed solutions. The experimental results indicate that tributyl phosphate (TBP) emerged as the optimal single extractant, achieving an effective acid extraction rate of 88.67% under a solvent ratio of 4:1 at a room temperature of 28 °C. A binary solvent system, composed of TBP with 20% sulfonated kerosene, demonstrated superior engineering feasibility due to its reduced viscosity and satisfactory extraction rate of 82.19%. Moreover, adsorption–desorption tests confirmed that the resin-based method effectively recovered acids from cleaning wastewater. Specifically, under optimal operational conditions—downstream adsorption at 0.3–0.5 bed volumes (BV) and 1.0 BV/h, coupled with counter-current desorption at 2 BV and 2.4 BV/h—the acid recovery rate reached ≥95% while removing ≥90% of aluminium ions. Additionally, employing 20% sulfuric acid solution for desorption in diffusion dialysis enabled cyclic desorption. Consequently, this study successfully achieved acid reuse and substantially lowered wastewater treatment costs, representing a promising advancement for anodic oxidation polishing processes. Full article

The article presents the results of research on the resilience of companies using management concepts such as Lean Management, Agile, and Six Sigma to the crises that companies have had to face in recent years: the COVID-19 pandemic, rising energy prices, and the war in Ukraine. The implementation of these management concepts should lead to process improvements and a reduction in the consumption of production resources, including energy. The aim of the study was to determine how these crises have affected the efficiency of companies and to determine whether the solutions used so far are sufficient or require modification. The authors used three research methods. Firstly, they analyzed the literature—scientific publications, studies, and expert reports. Secondly, they analyzed the financial results (net profits and share of Costs of Goods Sold in the value of Revenues) in the period before (2016–2019) and after the outbreak of the COVID-19 pandemic (2020–2023) of companies using Lean Management, Agile, and Six Sigma strategies and their combinations. To compare the effectiveness of these management methods, they also analyzed the financial results of international corporations and Polish companies. Third, they conducted a survey among Polish companies applying the Lean Management concept. The results of this research show that the crises of recent years, even if they caused a deterioration in financial performance, were short-lived as companies were able to adapt to the new conditions. Japanese companies using Lean Management increased their profits by an average of 55.56% between 2020 and 2023, and “Lean” American organizations even more (71.64%). Polish companies have been steadily increasing their profits for years (134.14% before the pandemic and 143.27% after the outbreak). The share of COGS will remain at a similar (high) level for many years to come. There are no significant increases in these costs due to crises in the companies’ environment (e.g., increase in energy prices), and, on the other hand, there is no tendency for them to decrease in a large proportion of companies. In the years 2020–2023, the largest decreases in the share of these costs occurred in companies combining Lean and Six Sigma (−11.85%). In companies that use the Agile strategy, there was an increase of 8.05%. However, these are average data, and the analysis of the results of companies from individual groups leads to the conclusion that it is not only the management concept that is important, but also how it is implemented in a given company. In addition, streamlining processes only by eliminating waste is not enough these days. It is necessary to use modern technologies (digital technologies, Industry 4.0). Increasing the efficiency of production or logistics processes leads to a reduction in energy consumption and external costs. However, new, specialized solutions are needed. The issue of energy efficiency is indeed gaining more and more importance in companies and is included in management concepts, e.g., in Lean Management. Full article