Waste Components Research Articles

How Indonesia’s Cities Are Grappling with Plastic Waste: An Integrated Approach towards Sustainable Plastic Waste Management

In Indonesia, plastic constitutes the second largest component of municipal solid waste; however, 58% remains uncollected. Most plastic recycling depends on informal sectors, accounting for only 10% of the total, leaving the remainder to potentially harm the environment. This paper analyzes how cities in Indonesia have tackled their plastic waste problems from the perspective of the integrated sustainable waste management framework. This study focuses on plastic waste management (PWM) in three cities: Bandung, Yogyakarta, and Magelang. Data were collected from 41 semi-structured interviews, a plastic waste composition data analysis, and site visits. The research outcomes include a comprehensive analysis of stakeholder roles, plastic waste flow, plastic waste composition data, and various challenges in PWM. This study identifies three main stakeholders in collecting plastic wastes: the Department of Environment as the main local government body, community-based waste banks, and private waste management companies. Most recyclable plastic waste is recovered through waste banks and private collection services. In 2022, the predominant types of plastic waste in Bandung, Yogyakarta, and Magelang City were soft plastics, thick plastics, and hard plastics, respectively. The challenges for the PWM stem from various aspects in political, legal, and institutional; environmental; financial and technical; and socio-cultural spheres. Positive trends towards an integrated system are observed, although full integration has not yet been achieved. The research recommends a multi-stakeholder cooperative approach involving municipal authorities, waste banks, and private collectors, responsive to local conditions and emphasizing sustainability aspects throughout waste management stages for a sustainable resource recycling in developing countries.

Comprehensive insights into the effects of acidogenic off-gas utilization on successive biogas production, microbial community structure and metabolite distribution during two-stage anaerobic digestion

Although two-stage anaerobic digestion (TSAD) technology has been investigated, the mechanisms regarding the impact of acidogenic off-gas (AOG) on successive methane production have not been well addressed. In this study, a novel TSAD system was designed. Food waste, as the main substrate, was co-digested with chicken manure and corn straw. The acidogenic gas beyond atmospheric pressure was introduced into the bottom of the methanogenesis reactor through a stainless steel diffuser. Results showed the addition of AOG increased the methane yield from 435.2 to 597.1 mL/g VSin in successive methanogenesis stage, improved by 37.2 %, and increased the energy yield from 9.0 to 11.3 kJ/g VSsubstrate. However, the theoretical contribution of hydrogenotrophic methanogenesis using H2 contained in AOG was only 15.2 % of the increased methane yield. After the addition of AOG, the decreased levels of ammonia nitrogen and butyrate indicate that the stability of the AD system was improved. The electron transfer system and co-enzyme F420 activity were enhanced; however, the decrease in acetate kinase activity indicates aceticlastic methanogenesis may have been weakened. The microbial diversity and species richness were improved by the added AOG. Methanosarcina was more competitive than Methanothermobacter, enhancing the syntrophic effect. The relative abundance of protein degradation bacteria norank_f_Anaerolineaceae and lipid degradation bacteria Syntrophomonas was increased. Metabolite analysis confirmed that the addition of AOG promoted amino acid metabolism, the biosynthesis of other secondary metabolism and lipid metabolism. The improved degradation of recalcitrant organic components (lipids and proteins) in food waste was responsible for the increased methane yield. This study provides an in-depth understanding of the impact of AOG utilization on successive methane production and has practical implications for the treatment of food waste.

Strengthening bio-circularity by reinforcing waste derived triphasic calcium phosphate to fabricate alumina toughened zirconia biocomposite with enhanced bioactivity

Animal waste bone (AWB) is a significant component of food waste, generating millions of metric tons annually and posing environmental and economic challenges due to improper management. Despite its rich bioactive compound content, AWB is underutilized. To address these issues, we propose incorporating waste-derived calcium phosphate phases from AWB into an alumina toughened zirconia (ATZ) composite, forming a Hydroxyapatite/Tricalcium Phosphate/Whitlockite-ATZ biocomposite. The high-temperature treatment during ATZ consolidation promotes Hydroxyapatite (HAp) formation and decomposition of HAp to Tricalcium phosphate (TCP) phases. Trace amounts of magnesium in AWB aid in Whitlockite (Wk) formation. This triphasic material exhibits excellent biocompatibility and osteoconduction, suitable for bone regeneration. ATZ ensures mechanical stability and counters degradation of calcium phosphate phases. Although AWB incorporation reduces mechanical properties, the resulting ATZ-AWB biocomposite meets acceptable biomaterial standards. The present ATZ-AWB biocomposite possess bulk density, apparent porosity, hardness, and bending strength in the range of 3.7–5.2 g/cm3, 3.6–17%, 2–9 GPa and 620–1000 MPa respectively. AWB incorporation enhances bioactivity, as demonstrated by increased apatite layer formation in simulated body fluid (SBF). By fostering bioactivity, this approach not only tackles biocircularity but also offers economically accessible biomaterials, thereby advancing environmental sustainability and socioeconomic progress.

Modification of the incinerator to prevent the emission of toxic air pollutant in biomedical waste incineration process at Base Hospital Udugama

Modification of the incinerator to prevent the emission of toxic air pollutant in biomedical waste incineration process at Base Hospital Udugama

Advancing in Cesium Retention: Application of Magnesium Phosphate Cement Composites.

A serious risk that harms the safe use of water and affects aquatic ecosystems is water pollution. This occurs when the water's natural equilibrium is disrupted by an excessive amount of substances, both naturally occurring and as a byproduct of human activities, that have varied degrees of toxicity. Radiation from Cs isotopes, which are common components of radioactive waste and are known for their long half-lives (30 years), which are longer than the natural decay processes, is a major source of contamination. Adsorption is a commonly used technique for reducing this kind of contamination, and zeolite chabazite has been chosen as the best adsorbent for cesium in this particular situation. The purpose of this research is to investigate a composite material based on magnesium phosphate cement (MPC). Magnesium oxide (MgO), potassium dihydrogen phosphate (KH2PO4), and properly selected retarders are used to create the MPC. The optimal conditions for this composite material are investigated through the utilization of X-ray diffraction, scanning electron microscopy, BET surface area analysis, and atomic absorption spectroscopy. The principal aim is to enable innovations in the elimination of radioactive waste-contaminated water using effective cesium removal. The most promising results were obtained by using KH2PO4 as an acid, and MgO as a base, and aiming for an M/P ratio of two or four. Furthermore, we chose zeolite chabazite as a crucial component. The best adsorption abilities for Cs were found at Qads = 106.997 mg/g for S2 and Qads = 122.108 mg/g for S1. As a result, zeolite is an eco-friendly material that is a potential usage option, with many benefits, such as low prices, stability, and ease of regeneration and use.

Distribution and survival of pathogens from different waste components and bioaerosol traceability analysis in household garbage room

Household garbage rooms release abundant bioaerosols and are an important source of pathogens; however, information on the distribution and survival patterns of pathogens in different waste components is limited. In this study, a culture method and 16S rRNA high-throughput sequencing were used to determine bacterial communities, culturable pathogens, and human bacterial pathogens (HBPs). The results showed that abundant culturable bacteria were detected in all waste types, and a large number of S. aureus was detected on the surface of recyclable wastes, whereas S. aureus, total coliforms, Salmonella, Enterococcus, and hemolytic bacteria were detected in food waste and other waste. The activities of these detected pathogenic bacteria decreased after 24 h of storage but re-activated within one week. Factors affecting the emergence of pathogens varied with different waste components. Sequencing results showed that Pseudomonas, Acinetobacter, and Burkholderia were abundant in the waste samples, whereas Achromobacter, Exiguobacteriums, Bordetella, and Corynebacterium were the primary pathogens in the bioaerosol and wall attachment. The results of traceability analysis showed that bioaerosol microbes were mainly derived from raw kitchen waste (5.98%) and plastic and paper contaminated with food waste (19.93%) in garbage rooms. In addition, bioaerosols were the main source of microflora in the wall attachment, which possessed high HBP diversity and required more attention. These findings will help in understanding the microbial hazards in different waste components and provide guidance for the control and risk reduction of bioaerosols during waste management and recycling.

Food waste to hydrochar: A potential approach towards the Sustainable Development Goals, carbon neutrality, and circular economy

Food waste is a common organic solid waste generated worldwide in significant quantities, and its proper treatment and management practices are hindered by high moisture content. However, hydrothermal carbonization (HTC) technique uses food waste moisture as the reaction medium and converts it into an environmentally friendly coal-like product, i.e. hydrochar. Food waste conversion to hydrochar via HTC has many benefits but a complex mechanism because each component of food waste has its own structural and chemical properties and interacts with the other components/chemical species during the process involving heterogeneous reactions, which significantly impacts the physio-chemical properties of food waste hydrochar (FWH). Due to high surface area, stability, carbon content, and regeneration capability, FWH is an attractive choice for numerous environmental applications, helps to achieve various Sustainable Development Goals (SDGs), and supports carbon neutrality and a circular economy. Given the importance of this topic, this review provides a comprehensive analysis of the advancements in HTC technology for producing hydrochar from food waste, as well as the carbonization mechanism of each constituent of food waste. The study also highlights the significance of different modification and activation methods used to enhance the primary drawback of FWH. We primarily intend to assess the application of FWH in accomplishing several SDGs, i.e., SDG 6.3 (pollutant removal from wastewater), SDG 7 (generate clean energy), SDG 13 (combat climate change, i.e., CO2 sequestration), SDG 15.3 (land and soil restoration). Our primary focus is to evaluate the future perspective of FWH via CO2 emission assessment, life cycle assessment, and techno-economic assessment, along with challenges in commercializing FWH, and propose significant avenues for future research. These insights are essential for determining the economic viability and environmental advantages of FWH as a valuable resource to accomplish several SDGs, achieve carbon neutrality, and promote a circular economy.

Modeling and evaluating costs and greenhouse gas emissions in solid waste management based on system dynamics in a mega-city: The case of Xi'an

With the escalating generation of municipal solid waste (MSW) and the increasing utilization of collection and transportation (C&T) vehicles within the MSW classification system, the associated costs and greenhouse gas (GHG) emissions from waste drop-off, as well as the C&T processes, have risen sharply. However, the mesoscopic view of the waste drop-off and C&T system is limited. Therefore, we divided the waste classification management (WCM) system into three subsystems: generation and drop-off, C&T, and disposal. Based on system dynamics theory, the logical relationships between relevant parameters in each subsystem were established. A WCM system dynamics model, which focused mainly on the drop-off and C&T processes, was constructed using Anylogic software. Using sensitivity, scenario, and uncertainty analyses, the economic impact and GHG emissions of the WCM system were analyzed in detail. The results showed that the waste drop-off and C&T processes accounted for 54.29–57.87% ($47.31 per ton) and 24.54–26.83% ($21.39–21.93 per ton) of the total cost in the whole waste management chain, respectively. GHG emissions were mainly generated in disposal facilities (116.84–257.86 kg CO2-eq/t), followed by C&T (19.02–20.55 kg CO2-eq/t) and drop-off processes (12.68–18.78 kg CO2-eq/t). The system cost and GHG emissions were significantly influenced by the components of the source-separated waste and operational parameters of the applied C&T vehicles. This study not only provides a basis for WCM policy formulation but also a tool for the design and optimization of waste C&T systems.

Tomato seed extract promotes health of the gut microbiota and demonstrates a potential new way to valorize tomato waste.

The current effort to valorize waste byproducts to increase sustainability and reduce agricultural loss has stimulated interest in potential utilization of waste components as health-promoting supplements. Tomato seeds are often discarded in tomato pomace, a byproduct of tomato processing, yet these seeds are known to contain an array of compounds with biological activity and prebiotic potential. Here, extract from tomato seeds (TSE), acquired from pomace, was evaluated for their ability to effect changes on the gut microbiota using an ex vivo strategy. The results found that TSE significantly increased levels of the beneficial taxa Bifidobacteriaceae in a donor-independent manner, from a range of 18.6-24.0% to 27.0-51.6% relative abundance following treatment, yet the specific strain of Bifidobacteriaceae enhanced was inter-individually variable. These structural changes corresponded with a significant increase in total short-chain fatty acids, specifically acetate and propionate, from an average of 13.3 to 22.8 mmol/L and 4.6 to 7.4 mmol/L, respectively. Together, these results demonstrated that TSE has prebiotic potential by shaping the gut microbiota in a donor-independent manner that may be beneficial to human health. These findings provide a novel application for TSE harvested from tomato pomace and demonstrate the potential to further valorize tomato waste products.

The avocado peel as a source of catechins: A comparison between extraction technologies and the influence of fruit variety

The bioactive components in agro-industrial wastes can be extracted to obtain compounds of industrial interest. The present study is focused on analyzing the composition of avocado peel extracts obtained by solvent extraction, ultrasound, and supercritical fluids by two varieties of avocado. As a result, differences in the composition of avocado peels and the yields presented in the extraction processes are evidenced. The solvent in the extractions strongly affected the active constituents' content and their antioxidant activities. The highest recovery of catechins is presented with ethanol at 50% v/v. Extraction with supercritical fluids increased the extraction yield to 17.14% w/w for the Hass variety and 14.20% w/w for the Lorena variety. However, in the case of the Lorena variety, supercritical fluids decreased the concentration of catechins. For the Lorena variety, ultrasound favored the extraction of catechins. The highest catechin concentrations corresponded to 151.96 mg of epicatechin and 60.77 mg of catechin per 100 g of Hass variety. The conditions that improved the extraction were 60 °C, 60 min, 0.2 mg/L (mg avocado peel per liter of solvent), and a frequency of 30 kHz. Avocado peel variety Lorena presented the highest concentrations of catechins under the same conditions (269.37 mg of epicatechin and 119.88 mg of catechin per 100 g of peel). The economic study showed better economic indicators for the Hass variety than the Lorena variety by the difference in extraction yields. The minimum production cost of the extract was 8.21 USD/kg using solvent extraction. From a technical point of view, this work made it possible to demonstrate the potential of avocado peels to obtain catechins, especially when ultrasound extractions are used. However, from an economic point of view, conventional techniques such as solvent extraction are recommended to extract flavonoids such as catechins.

New Jersey Leaves No Bite Behind: A Climate Change and Food Waste Curriculum Intervention for Adolescents in the United States.

Food waste is a major contributor to climate change. Schools offer a unique opportunity to educate on this issue while also reducing food waste generation; however, few climate-change education curricula that include a food waste component have been developed and tested with fidelity. Thus, the purpose of this cluster randomized controlled study was to assess the effectiveness of a climate change and food waste education program called NJ Leaves No Bite Behind (NJLNBB) among fifth-grade students. Lessons on food waste and sustainable food behaviors were developed that aligned with NJ Student Learning Standards for Climate Change and Next-Generation Science Standards. Participants (n = 162) completed pre- and post-test surveys that assessed knowledge, attitudes, self-efficacy, and behaviors. Post-test, the experimental group (n = 102) had significantly (p < 0.05) higher mean scores in knowledge, social norms, behavioral intentions, and perceived behavioral control compared to the control group (n = 60), with medium effect sizes, as determined by partial eta-squared. There were no significant between-group differences in mean score attitudes, self-efficacy, motivation to comply, or climate-friendly behaviors post-test. Almost three-quarters of participants who received the program agreed or strongly agreed the lessons were fun (75.5%), liked the card games (72.5), and learned a lot (78.4%). These findings are promising in terms of teaching adolescents the impacts of food waste on the climate.

Construction Waste from Perspective of the Disperse Systems Stabilisation Theory

Introduction. Every year, the scale of construction of buildings and structures in the large cities increases, thus leading to generation and accumulation of a considerable amount of a wide range of different sort of construction waste in various aggregate states. At the same time, each type of waste is characterised by a certain set of properties with the parameters that determine the possibility of its future reuse, therefore there arise the urgent problems to be solved by society not only concerning the reduction of the environmental pollution, but also disposal, and at best recycling the waste.The data on the specifications of the construction waste properties, which determine its behaviour in the environment, is extremely important for solving these problems.In the works of the native and foreign scientists on solving the construction waste management problems, the features of its behaviour in the environment were hardly ever studied, nor was the relationship between the distinctive features of its components and the environment characteristics enough revealed, and the boundary conditions referring to this relationship were not fully taken into account.That is why the authors present the results of the research on the classification of the distinctive features of the construction waste by grouping the parameters of their properties based on the theory of disperse systems stabilisation. Besides, the parameters of the construction waste properties have been investigated both for the dispersed phase and the dispersion medium, whereas the physical entity of the processes and phenomena observed in the construction waste has been chosen as the main classification criteria.Thus, the research aims to analyse and systematise the construction waste properties, based on the theory of disperse systems stabilisation in terms of extending the scope of the waste reuse in various sectors of economy.Materials and Methods. The object of the study is the construction waste generated in a result of the technological processes at the enterprises of the construction industry. Construction waste and its properties are investigated from perspective of the theory of disperse systems stabilisation. The classification of the parameters of the construction waste properties is carried out on the basis of the physical processes and phenomena that are characteristic for a particular type of waste. The construction waste properties and the parameters describing them are presented both for the dispersed phase and the dispersion medium.Results. As a result of the conducted research, the generalised parameters of the construction waste properties have been systematised based on the theory of disperse systems stabilisation in terms of extending the scope of the waste reuse in the business activities that leads to reducing the environmental pollution.Discussion and Conclusions. The proposed classification of the construction waste parameters will make it possible: – to change the behaviour of the waste in the environment aiming to reduce the environmental pollution and to extract the waste components from the environment for their further reuse in the business activity after pre-treatment resulting in the necessary property parameters;– to decrease waste stability, i.e. its ability to resist the external impacts, and thereby also ensure the reduction of the environmental pollution at the final stage of the waste life cycle.

Thermal Analysis of Combustible Components of Municipal Solid Waste

The use of municipal solid waste as a raw material for alternative fuel is a promising direction for waste recycling and substitution of solid fossil fuels. Therefore, selecting of fuel composition and studying of its properties is an urgent task. The aim of this work is thermal characteristics analysis of the combustible components of municipal solid waste, which are the most common in Ukraine, for further selection of a fuel composition that will satisfy the consumer's requirements. The goal is achieved by studying the thermal destruction of samples by thermogravimetry and differential thermal analysis when materials are heated to 1000 ºС in the presence of air oxygen. Paper, cardboard, plastic, biodegradable film, textiles, leather, wood were investigated in this work. The most important results are the received data on the characteristic temperatures of destruction stages, content of water, organic and mineral substances, ash, as well as the calculated values of rate and conditional thermal effect of decomposition of organic substances. Strong formation of gaseous substances was registered for samples of polyethylene and biodegradable film, polyethylene terephthalate and cotton fabric. These features should be considered in the technologies of production and combustion of fuel. The significance of the results also lies in the fact that it is recommended to use data on the thermal stability of materials in order to prevent their ignition during drying when developing fuel production technology. In addition, the calculated values of the conditional thermal effect made it possible to evaluate the thermal characteristics of the studied materials as components of solid alternative fuels.

A Review on Recycling of Waste Lead-Acid Batteries

Lead-acid batteries (LABs) have become an integral part of modern society due to their advantages of low cost, simple production, excellent stability, and high safety performance, which have found widespread application in various fields, including the automotive industry, power storage systems, uninterruptible power supply, electric bicycles, and backup power supplies. Hence, the use of LABs has greatly benefited human society and contributed to advancements in science and technology. However, the extensive use of LABs unavoidably leads to the generation of a significant amount of LABs waste. On one hand, if these waste LABs are not handled properly, any leakage can cause devastating damage to the natural environment and human health. On the other hand, waste LABs represent an important secondary resource for lead, with approximately 64.57% of global lead resources derived from recycled lead, making them a major source of lead worldwide. Moreover, approximately 85% of global lead resources are currently utilized for manufacturing LABs, and the recycling of waste LABs brings favourable prospects for the sustainable development of the energy storage industry. Therefore, the recycling of waste LABs is necessary and inevitable. In this paper, we have comprehensively reviewed the methods of recycling waste LABs. Particularly, we focused on the valuable component of waste lead paste and critically evaluated the pyrometallurgical and hydrometallurgical techniques associated with it. By categorizing and summarizing the characteristics of different methods, we have conducted a detailed comparison of these technologies, aiming to provide a comprehensive assessment of the advantages, disadvantages, status, and trends in LABs recycling technology. Additionally, the paper explores the necessity and impacts of recycling waste LABs from the perspectives of resource, energy, economy, environment, and society. It discusses the challenges faced by waste LABs recycling and presents the development prospects from both technical and non-technical point of views.

The Effect of Adding Coconut Coir Fiber on Compressive Strength, Tensile Strength, and Concrete Flexural Strength in Eco-Friendly Tetrapod Planning in Coastal Areas of IKN Supporting Cities

Beaches often experience erosion or abrasion problems caused by various factors, such as climate change which triggers rising sea levels, high waves, human activities such as beach reclamation, and infrastructure construction that is not environmentally friendly, triggering erosion on the coast. In the coastal area of the city that supports IKN, which is located in the Balikpapan area, Manggar Beach, also experiences abrasion which causes land to narrow in that area. The abrasion that occurs erodes the coastal area around 7-8 meters every year. To produce environmentally friendly infrastructure, this research carried out the addition of coconut fiber waste components to tetrapod concrete used for breakwater construction. In this research, variations in the addition of coir used were 0%, 1%, 2%, 3%, 4% and 5%. The aim was to find out how much influence the addition of coconut coir waste to the concrete mixture had on the compressive strength, tensile strength and flexural strength of the concrete in tetrapods. and produce concrete that uses coconut fiber waste as an alternative material for tetrapod concrete as breakwater armor. Based on the analysis results, the quality of the concrete was 23 Mpa. This value was determined based on wave generation analysis. In addition, it is known that variations in coconut fiber affect the slump, compressive strength, flexural and split tensile test values of concrete. Based on the slump test results, it was found that the greater the variation of coconut fiber in the concrete, the lower the resulting slump test value. In testing the compressive, flexural and split tensile strength, it was found that the optimal composition for adding coconut fiber was 3%, in this composition the amount of coconut fiber fiber was able to improve the mechanical properties of tetrapod concrete compared to other compositions.

Extraction processes of high added value molecules from wood waste: overview and comparison of processes for an eco-friendly recovery from paper industry by-product

The work aims to optimize an industrial greener extraction process of chemical components in wood waste from the paper industry. Extracts from a mixture of two species (Picea abies and Abies alba) were studied. Several parameters were found to play a key role in the extraction yield: to the conventional parameters such as the chemical composition of the extracting medium or the temperature, a key criterion was the choice of a process procedure in order to take into account the absorption of the solvent by the wood. The implementation of several operating modes, namely solid-liquid single-batch extraction, countercurrent extraction, percolation extraction, near supercritical, and supercritical fluid extraction is discussed in terms of yield and ease of implementation when scaling up.

Municipal Waste Characterization and Reduction Potential in Singaraja City

The Bengkala Landfill serves as the sole waste disposal site in the Buleleng Regency, and its current waste accumulation has exceeded the landfill's capacity. The local government has endeavoured to reduce the influx of waste to the landfill by establishing a Recycling Centre (RC) for waste processing. This research aims to analyse the generation and characteristics of waste in Singaraja City, as well as its recycling potential, to support RC planning. The study's method is to look at how much waste is made and what kinds of things are made from it by using measurements made by the local government of Buleleng Regency in line with the Indonesian National Standard (SNI) 19-3964-1994. The analysis reveals that Singaraja City produces approximately 606.23 kg/day of waste, with a density of 0.244 kg/L. Organic waste dominates, constituting 66.31% of the total waste composition. Food waste and foliage are the highest components of organic waste, underscoring the significance of food waste reduction, including composting. Paper, wood, and plastic contribute 8.23%, 1.41%, and 14.57% of the waste, respectively. The study of waste composition in Singaraja City reveals both opportunities and challenges in waste management and sustainability. Singaraja City can benefit from initiatives such as plastic reduction programmes, glass recycling, and hazardous waste management to achieve sustainable waste practices. Achieving these goals necessitates public education, policy interventions, recycling infrastructure development, and stakeholder collaboration.

Changes in coal waste DOM chemodiversity and Fe/Al oxides during weathering drive the fraction conversion of heavy metals

The long-term accumulation of coal waste on the surface during natural weathering leads to the inevitable migration of heavy metals contained in the coal waste, which increases the likelihood of environmental contamination and health risks. Dissolved organic matter (DOM) and Fe/Al oxides play crucial roles in the transformation and bioavailability of heavy metals. Thus, we analyzed the Fe/Al oxide content and DOM molecular composition in coal waste with different degrees of weathering and explored the influence of DOM chemical diversity and Fe/Al oxides on the potential mobility of heavy metals. Results showed that weathering-driven decrease in Fe oxides (Fed, FeO, and Fep decreased from 82.4, 37.5, and 3.6 mg∙L−1 to 41.3, 24.7, and 2.3 mg∙L−1, respectively) led to decreases in the reducible fractions of V and Cr. The potential environmental risks of more toxic metals of Cd and As, also increased as a result of the residual fractions decreased to 32.6 % and 41.3 %, respectively. Weathering caused an increase in oxygen-to‑carbon ratio, double-bond equivalent, modified aromaticity index, nominal oxidation state of carbon, and molecular diversity and a decrease in (m/z)w and (H/C)w, suggesting that the DOM of highly weathered coal waste possessed high unsaturation, aromatic structures, hydrophilicity, and strong oxidative characteristics. Additionally, although VMF and CrMF showed significant negative correlations with O/C ratio, polyphenolic, carbohydrates, and condensed aromatics, pH remained a key environmental factor determining the potential environmental risks of V and Cr by changing the residual fractions. The mobilities of Cd and As were significantly negatively correlated with those of Fe/Al oxides, particularly Fed, FeO, Fep, and Alp. Our findings contribute to the understanding of the impact of weathering on the geochemical cycling of different coal waste components, providing priority options for environmental risk prevention and control in coal mining areas.

Thermoviscosimetric characteristics of borosilicate glasses with regard to the promising area of low-melting compositions currently being developed for the removable small-scale melter designed by Mayak Production Association

Relevance. The need to obtain experimental data on dependence of thermoviscosimetric properties of the examined borosilicate glasses on temperature, in order to solve the problem of developing a low-melting composition of borosilicate glass for a small-scale melter designed by Mayak Production Association. Aim. To get the most complete characterization of the glasses under study using thermoviscometric measurements. Methods. Mathematical modelling, simplex-lattice design. Results and conclusions. One of the most effective methods of experiment planning, which allows, with a relatively small number of experiments, obtaining a mathematical model reflecting the dependence of the studied property of the mixture on the content of components in it, is the simplex experiment planning method. To simplify the solution of such a task, a group or groups of components are usually distinguished, in which the ratio of the mass fraction of the components does not change. In this article, three groups of components are taken – simulators of high-level radioactive waste, sodium and boron oxides, and glass frit. The authors have identified the most promising area, where the mass fraction of glass frit is from 67.5 to 75%, the mass fraction of sodium and boron is from 25 to 32.5% and the mass fraction of high-level waste components is from 0 to 20%. The paper presents the results of thermoviscometric measurements of 15 melts of low-melting borosilicate glasses of different compositions at temperatures ranging from 700 to 1,200°C. Using simplex-based mathematical models of experiment planning, domains of dependence of thermoviscosimetric characteristics of glass melts on their compositions were created. The authors identified the compositions of glass melts that are found within the viscosity limits determined as allowable for glass melt discharge during operation of the removable small-scale melter of Mayak Production Association design.

Nickel induces mitochondrial damage in renal cells in vitro and in vivo through its effects on mitochondrial biogenesis, fusion, and fission

Nickel (Ni) and its compounds are common, widely distributed components of hazardous waste in the chemical industry. Excessive exposure to Ni can cause kidney damage in humans and animals. We investigated the impact of Ni on renal mitochondria using in vivo and in vitro models of Ni nephrotoxicity, and explored the Ni nephrotoxic mechanism. We showed that nickel chloride (NiCl2) damaged the renal mitochondria, causing mitochondrial swelling, breakage of the mitochondrial cristae, increased levels of mitochondrial reactive oxygen species (mt-ROS), and depolarization of the mitochondrial membrane potential (MMP). The levels of the mitochondrial respiratory chain complexes I–IV were reduced in the kidneys of mice treated with NiCl2. In addition, NiCl2 treatment inhibited mitochondrial biogenesis in renal cells by down-regulating mRNA and the protein expression of TFAM, PGC-1α, and NRF1. Moreover, NiCl2 reduced the levels of the proteins involved in mitochondrial fusion, including Mfn1 and Mfn2, while significantly augmenting the levels of the proteins Fis1 and Drip1 involved in mitochondrial fission in renal cells. Taken together, these results suggested that NiCl2 inhibited mitochondrial biogenesis, suppressed mitochondrial fusion, and promoted mitochondrial fission, resulting in mitochondrial dysfunction in renal cells, ultimately causing renal injury. This study provided novel insights into the mechanisms of nephrotoxicity of Ni and new ideas for the development of targeted treatments for Ni-induced kidney injury.