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The paper presents the possibility of evaluation of using apple pomace as an alternative solid fuel. Taking into account the high initial moisture content of the raw material, preliminary drying using a highly efficient filtration drying method is proposed. Based on the experimental data, the following were determined: generalized dependencies describing the change in the moisture content of raw materials and the drying duration; dependence of hydraulic resistance on the stationary layer height of the material during the filtration drying process; technologically feasible parameters of filtration drying (layer height of the dried material 120 mm, temperature of the thermal agent 90 °C, velocity of the thermal agent 1.76 m/sec); energy consumption for the removal of 1 kg of moisture under these process parameters is 21990.02 kJ/kg H2O or 6.11 kW h/kg H2O. An estimated calculation of the industrial drying of apple pomace from a moisture content of 83 % wt. to 14 % wt. by the filtration method in terms of drying ≈ 1000 kg of raw materials established the total energy consumption for removing 1 kg of moisture of 6.36 kW h/kg H2O, and the total amount of energy required for the drying process of 92977.11 kJ/kg dry mat. For comparison, an estimated calculation of apple pomace drying in a rotary dryer was performed, which showed the advantage of the filtration method. The samples of briquetted solid fuel from dried apple pomace were made and their main characteristics were investigated: higher calorific value (≈ 19438 kJ/kg), residual moisture content (< 1 % wt.), ash content (≈ 0.55 % wt.). The compliance of the created briquettes characteristics with the requirements of existing European standards for solid fuels is shown. With rational preliminary preparation of secondary raw materials of plant origin, their use as solid fuels can become an alternative to slowly renewable or non-renewable fuel sources, solve the problem of accumulation of industrial waste with a limited shelf life, and generally improve the environmental situation.

Pursuing enhanced nutritional value in bakery products through technological advancements and new recipes is a promising facet of the food industry. This study focuses on incorporating rice and buckwheat brans, additional raw materials rich in biologically active substances, into bakery products. Utilizing a second-order rotatable plan, optimal ratios were determined—5% rice bran and 10% buckwheat bran. The application of these brans influenced dough and bread quality, reducing sugar content by 5% in dry form and 29% in the fermented brew, potentially aiding in diabetes prevention and cholesterol control. Introducing brans, especially in fermented brew, positively impacted microbiological stability, reducing the risk of mold and potato disease. The developed bread technology using rice and buckwheat brans in fermented brew significantly increased nutritional value, satisfying adult daily protein needs by 31.2%, fats by 15%, and dietary fibers by 18.4%. This innovative approach ensures a sufficient intake of essential vitamins and minerals, showcasing a promising avenue for creating healthier and more nutritious bakery products. [ABSTRACT FROM AUTHOR]

Calculations and experimental methods are used to study the collective and individual effect of Zn, Mg, Fe, and Si additions on the phase composition and structure of cast and cold-rolled aluminum alloys containing 2% Cu and 1.5% Mn. The combined additions of these elements of more than 3% to the base alloy were found to allow the mechanical properties of cold-rolled alloys to be kept at a level of properties of deformed base alloy despite the substantial complication of the phase composition. This largely is due to the completely fixing iron into the eutectic inclusions of the Al15(Fe,Mn)3Si2 phase. From this, it follows the fundamental possibility of using a variety of secondary raw materials for the preparation of this alloy, which does not require homogenizing and quenching. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Almaty Technological University is the property of Almaty Technological University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study was to evaluate the effect of extruded preparations on the bioactive and nutritional properties, vitamin B content, volatile compound profile, and quality of whole wheat bread. Extruded preparations based on stale bread (secondary raw materials) and apple pomace (byproducts) were used as bread additives. It was found that the preparations did not enrich the bread in protein but in health-promoting compounds, especially gallic acid, protocatechuic acid, caffeic acid, p-coumaric acid, rutin, quercetin, and B vitamins. Extruded preparations had a positive effect on the quality of the bread produced, such as yield and cohesiveness, and gave it a pleasant aroma. It was shown that among all the examined bread samples with added extruded preparations of stale bread, the cornmeal and apple pomace bread samples with 15% extruded preparation (containing 55% cornmeal, 30% stale bread, and 15% apple pomace) had sufficient nutritional value, the highest amounts of gallic acid, protocatechuic acid, p-coumaric acid, caffeic acid, rutin, and quercetin; medium amounts of ellagic acid; high antioxidant activity determined in vitro using four methods (by DPPH, ABTS, power (FRAP), and Fe(II) chelating assays); adequate quality; and significant amounts of vitamins, especially B1, B2, and B3. This type of extruded preparation should utilize apple pomace, which is a byproduct, and stale bread, which is a secondary waste. Such a combination is an excellent low-cost, easy, and prospective solution for the baking industry that could be applied to obtain bread with elevated nutritional value and enhanced health potential, as proven in this publication. [ABSTRACT FROM AUTHOR]

The shift from the current extractive linear production and consumption system to a circular economy (CE) has been heralded as a way to reduce the negative environmental and social impacts of human economic activity. The European Union (EU) has committed to leading the way to a worldwide CE, with the development of an international market of recyclable raw materials (RRM) as one of the main pillars of its strategy. However, there is extensive evidence regarding the unequal distribution of the economic benefits and environmental damages related to international trade. Therefore, the objective of a global fair transition to a CE may be undermined if the related markets continue to reproduce the prevailing patterns of ecologically unequal exchange. In order to test whether or not this is the case, this research studies the physical trade balance and the terms of trade on the recent RRM trade flows from, to and between the EU27 member states. [ABSTRACT FROM AUTHOR]

Recycling and reusing phosphorus in agriculture can reduce the consumption of natural phosphorus resources, which are continuing to shrink. Phosphorus fertilizers made from renewable raw materials (sewage sludge ash, animal bones, dried animal blood) and activated with phosphorus solubilizing microorganisms (Bacillus megaterium, Acidithiobacillus ferrooxidans) offer an alternative to conventional fertilizers. These products should meet consumer and environmental safety standards. In this paper, based on field experiments conducted in northeast Poland, the effects of waste-derived biofertilizers on selected parameters of wheat yield quality are discussed. The study focuses on the technological properties of the grain (hectoliter weight, hardness index, Zeleny index, starch, wet gluten, and protein content), the content of proteogenic amino acids, macro- and micronutrients, and selected toxic elements in the grain. The quality parameters of wheat grain were not affected by the tested biofertilizers applied in P doses up to 35.2 kg ha−1, nor by conventional fertilizers. [ABSTRACT FROM AUTHOR]

In many countries around the world, the thermal treatment of waste plays an important role in the waste-management system. As a result, electricity and heat are produced. However, solid residues are produced in the form of bottom ash, fly ash (FA) and air pollution control (APC) residues. Alternative raw material resources are currently being sought, one of which may be anthropogenic materials from waste thermal treatment processes. This paper presents the results of a study on the trace element content of FA and APC residues from three different installations: municipal solid waste incineration (grate boiler), sewage sludge (fluidized bed boiler) and hazardous waste (rotary kiln). Research methods such as ICP-MS (inductively coupled plasma mass spectrometry), ICP-AES (inductively coupled plasma/atomic emission spectroscopy) and XRD (X-ray diffraction) were used. The results obtained indicate that the chemical composition of FA and APC residues depends mainly on the type of waste being converted, the thermal process and the flue gas treatment method. Ash from sewage sludge incineration in particular contains significant amounts of P and Sb - elements classified as critical raw materials (CRM). In addition, they also contain other valuable metals such as Ag and Zn, in amounts far exceeding the average crustal abundance. In addition, residues from the incineration of hazardous waste may pose a potential risk to the environment due to the presence of significant amounts of heavy metals such as Pb, Cd and Hg. [ABSTRACT FROM AUTHOR]

Bread and bakery products are one of the main food products, and their quality does not always meet the requirements of modern nutrition science. One of the directions of solving this problem is the creation of new safe varieties of bakery products of functional purpose to correct the nutrition of the population. The article considers the causes of microbial spoilage, the negative influence of mold fungi and spore-forming bacteria of the genus Bacillus on the safety of bread with the use of secondary raw materials of grain crops processing. The main objects of research were bakery products with the use of rice and buckwheat brans, prepared by the traditional method and on complex sourdough starter. Studies on the influence of the method of rice and buckwheat brans application on resistance to mold and potato disease infection were conducted. [ABSTRACT FROM AUTHOR]

The research investigates the patterns of rare earth elements (REE) extraction from ash-slag waste of thermal power plants using sintering processes. The aim of the study was to determine the optimal parameters for the process: the composition of the flux, the ratio of the sintering flux to the waste, and the sintering temperature. It has been shown that the change in the type of sintering reagent, its ratio to the waste, and the process temperature significantly affect the degree of REE extraction from the insoluble form in ash-slag to the soluble form in sinter. The optimal sintering temperatures (300-4500C) for the extraction of REE from ashslag waste have been determined. The influence of various sintering reagents on the process of REE extraction from ash-slag waste has been investigated. It has been shown that the use of sodium hydroxide as a sintering reagent allows increasing the degree of REE extraction from waste up to 100%. Based on the analysis of the obtained experimental data, the main technological parameters of REE extraction in sinter have been determined. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Almaty Technological University is the property of Almaty Technological University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

An effective air-impact method for mechanochemical processes of activation of secondary raw materials in the production of building materials has been proposed. In order to increase the specific surface area of the binder and accelerate the strength gain of fast-hardening concrete mixtures, a model for calculating aeroactivators has been created on the basis of new technological equipment for activating cement, sand, and production waste. The proposed model establishes the dependence of the destruction rate of the contaminating shell of particles on the mechanical impact of the blows and physical–mechanical characteristics of the materials. To improve the performance characteristics of the aeroactivator, experimental studies have been carried out, the results of which made it possible to determine rational parameters of the improved installation and confirm the correctness of the developed design. [ABSTRACT FROM AUTHOR]

The main objective of this manuscript is to collect, classify, and compile all available data about secondary mineral sources of REEs in the South-Eastern Europe (SEE). The material is generated from the extracting and processing sector, that might be possibly transformed in the business process becoming an important raw material for another industry. The management inventory guide will strengthen communication and dissemination efforts and simultaneously contribute to Europe's self-sufficiency and support transitioning to green and digital technology. Identification of the knowledge gaps associated with secondary sources of REEs in SEE will contribute to connections between all partners being involved at the beginning, during the lifetime of products and at the end of the life cycle, represented with deposit owners, technology developers and potential processors, producers, and potential users. At the investigated area it was found 1835 individual landfills, most of them belonging to waste rocks. The total quantity of all material in SRM is about 3.2 billion tons on an area of about 100 km2. The largest 95 individual landfills were selected as potential prospective landfills, containing about 1600 million tons of material. The estimated total potential of REEs (ΣREE) is more than 200 Kt. The largest quantities are found in landfills for coal fly ash and Cu flotation, which correspond to more than 80% of the ΣREE. Most of the promising sites are located in Serbia and North Macedonia. It has been calculated that the valorisation potential and perspectivity of REE2O3 is about 32.5 billion USD (prices from December 2022). According to the average concentrations of REEs, the most prospective are the red mud dams but their total volume is limited compared to massive amounts of coal fly ash landfills. The REEs content in all type of investigated materials, especially in coal fly ash in North Macedonia is twice as high as in other countries. [ABSTRACT FROM AUTHOR]

This geospatial dataset provides a compilation of findings from an evidence-based review of site-specific resource assessments of mining and metallurgical residues. Information pertaining to location, target material, geological knowledge, extractability, resource classification and stakeholder perspectives was collected from publicly available reports, articles, academic theses, and databases. The datasetincludes 44 relevant data attributes from 64 mining and metallurgical sites in 27 countries. Resource classification is available for 38 sites. The dataset can be used by evaluators of recovery projects, authorities that provide permits, as well as by decision makers in support of developing regulatory policies. The dataset facilitates future addition of sites by the research community and can be further used as a starting point to bridge the estimates on recoverable quantities to the United Nations Framework Classification (UNFC). The UNFC is a universally applicable scheme for the sustainable management of all energy, primary and secondary mineral resources. Its use is stimulated by the European Commission and is intended to be adopted by geological surveys to harmonize the data on the availability of primary and secondary raw materials in Europe in future.

Purpose. This paper aims to analyze and classify construction and demolition waste. It is necessary that this classification not only reflects statistical data on waste generation, but also serves as an information basis for the integrated waste management system (IWMS). The main task of this system is to maximize the involvement of waste in economic recycling and to objectively reflect the technological capabilities of its processing. This is extremely important in the context of the implementation of European waste management principles and the implementation of the National Waste Management Strategy in Ukraine until 2030. Methodology. The article considers the problems of construction waste management within the framework of the National Waste Management Strategy in Ukraine until 2030, which provides for the implementation of measures and principles of waste management, including construction waste. The author analyzes the management problems in the field of construction and demolition waste, which substantiates the need to classify construction waste with the simultaneous harmonization of processing methods and technologies. Construction activities are inextricably linked to the management of various types of resources, among which secondary materials play a key role in the implementation of construction processes. The ability to effectively manage the flows of these secondary resources is critical to ensuring the sustainability and efficiency of construction production. In this context, the study of the importance of managing the flows of secondary resources becomes an integral part of strategies for optimizing construction processes. Findings. Construction waste from the demolition of buildings and structures is unique due to its size and the need to prepare it for primary crushing. This is especially true in the context of implementing the concept of renovation of the outdated housing stock. Various static and dynamic methods of destruction of building materials, in particular, impact and vibration, have been investigated, with dynamic methods being characterized by lower energy consumption. Originality. The work reflects the formation of theoretical and methodological directions based on the use of recycled materials in construction, as well as a comparative characterization of various methods of destruction of building materials. Practical value. The possibilities of recycling construction waste, in particular, their maximum involvement in recycling, which meets the goals of the Strategy of Ukraine, provides 50% of waste recycling.

At the EU level, the transition to a more circular economy by reducing the demand for primary resources and energy has the potential to increase resilience, reduce dependence on energy and material imports, while contributing to the transition to clean energy. Thus, increasing the use and supply of secondary raw materials as essential production factors for a wide range of activity sectors within the EU economy will facilitate the achievement of sustainable development targets in the future. In this sense, the aim of the paper was to study the structure and the dynamics of the Romania’s trade, both import and export, in recyclable raw materials as a member state of the European Union. The analysis sought to highlight the main structural and quantitative changes occurring in the period 2004-2021, as well as Romania's position both in relation to the other member states and the EU average, taking into account the fact that the transition to the circular economy differs from one country to another.

Pursuing enhanced nutritional value in bakery products through technological advancements and new recipes is a promising facet of the food industry. This study focuses on incorporating rice and buckwheat brans, additional raw materials rich in biologically active substances, into bakery products. Utilizing a second-order rotatable plan, optimal ratios were determined—5% rice bran and 10% buckwheat bran. The application of these brans influenced dough and bread quality, reducing sugar content by 5% in dry form and 29% in the fermented brew, potentially aiding in diabetes prevention and cholesterol control. Introducing brans, especially in fermented brew, positively impacted microbiological stability, reducing the risk of mold and potato disease. The developed bread technology using rice and buckwheat brans in fermented brew significantly increased nutritional value, satisfying adult daily protein needs by 31.2%, fats by 15%, and dietary fibers by 18.4%. This innovative approach ensures a sufficient intake of essential vitamins and minerals, showcasing a promising avenue for creating healthier and more nutritious bakery products.

The particulates from recycled construction material tend to generate dust, because of a wide particle size distribution. This dust release in gaseous environment is in most cases an unintended side effect. It is a loss of resources, a negative impact on people and the environment. In the context of this work, various mineral materials with different size distribution and identical moisture content were investigated for the tendency to dust. [ABSTRACT FROM AUTHOR]

Although most people agree that recycling materials is a good thing to do, not many of them know how materials are recycled. Wood is a prime example. It is highly likely that many people who are reading this have never thought in detail about how wood is recycled. This paper discusses the need for recycling, the current wood recycling practices, the challenges currently facing the wood recycling sector and how these challenges are being addressed. [ABSTRACT FROM AUTHOR]

Urban areas comprise less than 1% of the Earth's land surface, yet they host more than half the global population and are responsible for the majority of global energy use and related CO2 emissions. Urbanization is increasing the speed and local intensity of water cycle exploitation, with a large number of cities suffering from water shortage problems globally. Wastewater (used water) contains considerable amounts of embedded energy and recoverable materials. Studies and applications have demonstrated that recovering or re-capturing water, energy, and materials from wastewater is a viable endeavor, with several notable examples worldwide. Reclaiming all these resources through more widespread application of effective technological approaches could be feasible and potentially profitable, although challenging from several points of view. This paper reviews the possibilities and technical opportunities applicable to the mining of resources within the urban water cycle and discusses emerging technologies and issues pertaining to resource recovery and reuse applications. The present and future sustainability of approaches is also discussed. Since sewage management issues are not "one size fits all", local conditions must be carefully considered when designing optimal local resource recovery solutions, which are influenced not just by technology but also by multiple economic, geographical, and social factors. [ABSTRACT FROM AUTHOR]

In recent years, the world has witnessed one of the most severe raw material crises ever recorded, with serious repercussions for maintaining its agri-food supply chain. This crisis risks dramatically impacting the poorest areas of the planet and poses profound reflections on global food security. In this complex geopolitical context, the recovery and recycling of renewable resources have become an obligatory path and, today, more than ever, essential in the fertiliser industry. To achieve these objectives, TIMAC AGRO Italia S.p.A. has undertaken a research activity to review the formulation of fertilisers by diversifying the raw materials used and introducing recycled raw materials. This article carried out a life cycle assessment (LCA) on four fertilisers to identify and quantify whether the changes influenced the environmental impacts, highlighting how applying the circular economy within industrial processes can reduce the pressure on natural resources. The results demonstrate that the global warming potential (GWP) impacts of the different reformulated fertilisers show a considerable variation of 4.4–9.2% due to the various raw materials used, the nitrogen content, and related emissions deriving from environmental dispersion. This study shows the importance of the LCA methodology to analyse and quantify the impact categories generated on the life cycle of fertiliser production and to identify the optimal by-products and end-of-waste for the fertiliser industry to find a synergy between environmental and agronomic performance. It also highlights the relevance of the transition to circular production and consumption systems to reduce environmental pressures and their effects on communities and ecosystems without compromising yields. Finally, the positive results encourage accelerating the circular transition and finding alternatives to virgin-mined raw materials. [ABSTRACT FROM AUTHOR]

The article substantiates the effect of the concentration of polymer thickener on such basic properties of the plastic lubricant as dripping temperature (td.p., ℃) and adhesive properties (ADG). It was defined that, unlike (td.p., ℃), the ADG indicator is more informative for defining the optimal concentration of the polymer thickener in plastic lubricants produced from secondary raw materials. Determination of the ADG indicator was performed in a laboratory centrifuge, based on the amount of plastic lubricant that remained on the metal plate after the study. This amount should be at the level of 50 % of the initial value. Experimental studies have shown that the optimal concentration in the composition of the lubricant is: in the case of HDPE, 5.0 % for SAE15W-40 oil, 4.3 % for SAE 75W-90 oil, 6.3 % for BP Energol CS68 and HLP-46 oil; in the case of LDPE, this concentration is equal to 7.0 % for SAE15W-40 oil, 5.2 % for SAE 75W-90 oil, 7.4 % for BP Energol CS68 and HLP-46 oil; in the case of PP, this concentration is equal to 7.5 % for SAE15W-40 oil, 6.2 % for SAE 75W-90 oil, 8.0 % for BP Energol CS68 and HLP-46 oil. [ABSTRACT FROM AUTHOR]

The relevance of the work is caused by the need to study the problems of quite volatile world market of tungsten raw materials. Objective: to study the state of the world mineral resource base of tungsten and its extraction, to assess the criticality of the tungsten raw material world supply. Methods: content analysis of information collected from open sources on the dynamics of mining tungsten raw materials, as well as information on its reserves and resources. Results. 3,9 million tons of tungsten were mined in the world from 1913 to 2020. World production volumes increased from 4 to 7 thousand tons/year in 1913–1915 to 75 to 90 thousand tons/year in 2011–2020. China is the leader in the production of tungsten products, which supplied 25–35 % of the world production of tungsten raw materials until the 1980s, and since 1983 has occupied a dominant position in the supply of tungsten products (75–85 %). Russia supplies 5–10 % of the world supply of tungsten concentrates. New countries-suppliers of tungsten raw materials: Vietnam (up to 6,5 % of the world supply), Mongolia, Rwanda, Zimbabwe, have emerged. In the XXI century, in the conditions of high prices for tungsten products, there has been a tendency to revive old tungsten production facilities in Britain, Spain, Bolivia, Australia, Canada, Myanmar. A project of resumption of operation of the Tyrnauz Mining in Russia is under consideration. The world's existing reserves (3,66 million tons W) and resources (10,92 million tons W) of tungsten raw materials are enough for more than 70 years at the current level of consumption. 32,7 % of these reserves and 57,5 % of potential resources fall on China. Five of ten largest tungsten deposits in the world are located in China. Russia, Kazakhstan, Canada and Bolivia have significant reserves and forecast resources of tungsten. New deposits may be discovered in the little-explored territories of Myanmar, Mongolia and India in Asia, Congo, Rwanda, Burundi and Zimbabwe in Africa. Due to the significant share of tungsten raw material world production and a very high share of world trade in tungsten products from their production in one country – China, both tungsten raw materials and other commercial tungsten products will continue to be critical goods in industrialized countries in the foreseeable future.

The aim of this study was to evaluate the effect of extruded preparations on the bioactive and nutritional properties, vitamin B content, volatile compound profile, and quality of whole wheat bread. Extruded preparations based on stale bread (secondary raw materials) and apple pomace (byproducts) were used as bread additives. It was found that the preparations did not enrich the bread in protein but in health-promoting compounds, especially gallic acid, protocatechuic acid, caffeic acid, p-coumaric acid, rutin, quercetin, and B vitamins. Extruded preparations had a positive effect on the quality of the bread produced, such as yield and cohesiveness, and gave it a pleasant aroma. It was shown that among all the examined bread samples with added extruded preparations of stale bread, the cornmeal and apple pomace bread samples with 15% extruded preparation (containing 55% cornmeal, 30% stale bread, and 15% apple pomace) had sufficient nutritional value, the highest amounts of gallic acid, protocatechuic acid, p-coumaric acid, caffeic acid, rutin, and quercetin; medium amounts of ellagic acid; high antioxidant activity determined in vitro using four methods (by DPPH, ABTS, power (FRAP), and Fe(II) chelating assays); adequate quality; and significant amounts of vitamins, especially B1, B2, and B3. This type of extruded preparation should utilize apple pomace, which is a byproduct, and stale bread, which is a secondary waste. Such a combination is an excellent low-cost, easy, and prospective solution for the baking industry that could be applied to obtain bread with elevated nutritional value and enhanced health potential, as proven in this publication.

Recycling and reusing phosphorus in agriculture can reduce the consumption of natural phosphorus resources, which are continuing to shrink. Phosphorus fertilizers made from renewable raw materials (sewage sludge ash, animal bones, dried animal blood) and activated with phosphorus solubilizing microorganisms (Bacillus megaterium, Acidithiobacillus ferrooxidans) offer an alternative to conventional fertilizers. These products should meet consumer and environmental safety standards. In this paper, based on field experiments conducted in northeast Poland, the effects of waste-derived biofertilizers on selected parameters of wheat yield quality are discussed. The study focuses on the technological properties of the grain (hectoliter weight, hardness index, Zeleny index, starch, wet gluten, and protein content), the content of proteogenic amino acids, macro- and micronutrients, and selected toxic elements in the grain. The quality parameters of wheat grain were not affected by the tested biofertilizers applied in P doses up to 35.2 kg ha−1, nor by conventional fertilizers.

Sewage sludge is a type of waste that has high health and environmental risks associated with its reuse. Moreover, sludge has been neglected in global circular economy targets because it is generated in considerably lower quantities than municipal solid waste. At the same time, European Union's transition towards circular economy has set the need to reduce the amount of waste and to promote the production of secondary raw materials. Many countries have developed national strategies for sludge management to reach their sustainability goals. In Latvia, the current sludge management approaches include land application, composting and anaerobic digestion which all utilize sludge as an organic fertilizer. As an alternative to current management practices, resource recovery is put forward as a solution that is in agreement with EU policy. Carbohydrates (including cellulose), proteins and lipids were selected as candidates for energy and materials recovery from sludge. For the first time, this study demonstrates a comprehensive assessment of Latvian municipal sewage sludge composition and offers the theoretical yields of secondary resources on a yearly basis. Primary, secondary, and anaerobically digested sludge from 13 wastewater treatment plants (WWTPs) in Latvia was characterized in this study. The most abundant sludge type – secondary sludge – contained 18.5% proteins, 9.8% lipids and 2.6% cellulose per TS. On a yearly basis, secondary sludge from all Latvian WWTPs could provide 2530 t proteins, corresponding to 750 t protein-based fertilizer. Primary sludge contained 23.9% proteins, 9.1% lipids and 7.1% cellulose per TS. Primary sludge could provide 763 t/a carbohydrates, including 545 t/a cellulose. The currently available secondary and digested sludge would yield 727 t bioethanol, corresponding to 4.0% of the national biofuel consumption. This work applies the concept of resource recovery to the Latvian wastewater sector and shows the potential of simultaneously addressing waste and wastewater management issues.

The recycling of photovoltaic modules has been a topic of increasing interest over the last years. At industrial scale, delamination of the module structure, which represents the first step in the recycling process, is currently achieved by multi-stage crushing. However, the quality of the outputs obtained through subsequent processing is low and offers room for improvement. Milling was investigated as an alternative physical delamination method. Lab-scale experiments were conducted to evaluate the applicability of the technology in general, as well as comparing a process by which all non-glass layers are removed at the same time (one-step) with one where the backsheet is removed as a separate fraction (two-step). Furthermore, a qualitative and quantitative analysis of the resulting outputs in each case was performed. Results show effective delamination by the milling process. Advantages in comparison to the currently used delamination techniques are identified in regard to the quality of the recovered glass, which is separated directly during delamination as well as the fact that the subsequent processing can therefore be focused on the polymers, metals and silicon contained within the removed materials. Some possibly problematic aspects in regard to upscaling have also been identified and discussed. While the two-step process enables the recovery of more homogenous outputs, it is also associated with a higher effort regarding input characterization and the milling process itself. In order to reach a conclusion about which process option is more feasible, additional investigations concerning the milling process, the input material and the output fractions are needed. [ABSTRACT FROM AUTHOR]

This article is dedicated to the possibilities of using new alternative raw materials in the structure of aerated autoclaved concrete. Primary sources of raw materials are exhaustible and their price is increasing. According to the ecological requirements of the European Union, it is necessary to find many more ecological ways how to produce building materials. Production of aerated autoclaved concrete is for such utilization potentially suitable. It is well known, that the partial replacement of siliceous constituents is possible. This article is focused on the use of dispersed siliceous waste material with fiber‐like grains (e.g., waste fibers from the production of reinforcement fabrics and glass). The input raw materials are standard aerated autoclaved concrete based (cement, lime, silica sand). As an aerating agent was the aluminum powder. This article is dedicated to the determination of basic physical‐mechanical properties and a suitable amount of filler determination. The amount was determined on the basis of the constructive quality coefficient. It seems that partial replacement of the siliceous constituent by fiber‐like materials leads to improvement of properties. [ABSTRACT FROM AUTHOR]

Red mud (RM) is the main residue produced by the alkaline extraction of alumina (Al2O3) from bauxite, and it contains valuable metals such as iron (Fe), aluminium (Al), titanium (Ti), magnesium (Mg), manganese (Mn), rare earth elements, etc. This research aimed to investigate the biologically induced leaching of some valuable elements from raw RM without preliminary biomass enrichment and inoculum, simultaneously reducing RM polluting potential and extracting metals for their subsequent recovery within a circular economy-based approach. In addition to the missing inoculum, such an approach is challenging since high RM alkalinity and pH, as well as the absence of any sulphides, constrain the use of the most common biohydrometallurgical techniques. Red Muds from two European locations were tested (RM-I and RM-II, respectively). Bioleaching tests were performed at different temperatures (T = 22 °C and 28 °C; and also 15 °C for RM-II) and solid-to-liquid ratios (S/L = 2%, 5%). A sudden drop in pH from alkaline to constant neutral/acidic values was observed in almost all tests, and such results were attributed to biological activity since abiotic tests did not show any pH decrease. The best results in terms of extraction were achieved with RM-II, in particular for Al, Mg and Mn (17%, 42% and 47%, respectively). At 2% S/L, the highest temperature allowed for a better metal release, while at 5% S/L, the highest extraction of Al, Mg and Ti was observed at 22 °C. As expected, iron was less available to leach at the achieved pH values, as it was mostly present as hematite in both RMs. Finally, the first microbiological characterisation of the autochthonous biomass selected during the bioleaching treatment of RM was provided. [ABSTRACT FROM AUTHOR]

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Copyright of Scientific Bulletin of National Mining University is the property of National Mining University, State Higher Educational Institution and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose. The research purpose is to study the physical-chemical properties of ash and slag waste generated during the coal combustion at the Ekibastuz field in Kazakhstan, to determine the possibility of using waste as a secondary resource to reduce the negative human impact on the environment. Methods. The research uses the methods of X-ray phase and differential thermal analysis, as well as chemical analysis. The X-ray phase analysis makes it possible to determine the phase composition and structure of ash and slag wastes, while differential thermal analysis is used to study their behavior with temperature changes. A chemical analysis is performed to determine the composition of ash and slag. Findings. The chemical and granulometric composition of ash and slag waste from the Ekibastuz field coal combustion has been determined. Analysis of the ash chemical composition showed that its main components are silicon and aluminum oxides, as well as a significant amount of iron oxide. The results obtained confirm the possibility of using ash and slag waste as a secondary raw material to reduce the negative impact on the environment. Originality. It has been revealed that the thermal conductivity, ultimate strength and water-absorption of ceramic brick samples depend on the amount of ash added and the firing temperature. The possibility of obtaining building materials with minimum cement content has also been substantiated, which is a new and promising approach, given the high cost of cement as the main building material. Practical implications. The practical value of the research is in solving environmental problems associated with the use of ash and slag waste. Using these wastes as a secondary raw material, it is possible to reduce the anthropogenic burden on the environment, as well as the volume of ash dumps. In addition, vacant land previously occupied by ash and slag mixtures can be used for economic purposes. [ABSTRACT FROM AUTHOR]

This work considers the possibilities of complex processing of ash and slag waste of thermal power plants. The work contains technological data of acid, alkaline and fluoride processing of ash slag. The chemical composition of ash and slag waste of the Dnipropetrovsk region was established. It was established that when using acid technology of processing with mineral acids, preliminary magnetic separation is a mandatory condition. Leaching of the obtained magnetic and non-magnetic fractions is carried out at 105°C for 2 hours. At the same time, a more complete extraction is observed from the magnetic fraction. In addition, it is possible to remove liquid and scattered elements. It has been established that a wide range of sodium-based alkaline compounds can be used in alkaline processing technology. At the same time, scandium, gallium and alumina can be extracted. The process temperature is 50°C for 2 hours. It was established that for more complete processing of waste, the sintering process is carried out at 1400-1500°C. The residue from alkaline processing is used in construction. It has been established that when using the fluoride technology of ash slag processing, aluminosilicate compounds can be processed more fully due to the extraction of silicon, which makes it possible to gradually obtain aluminum and iron from the waste. [ABSTRACT FROM AUTHOR]

The construction sector contributes significantly to waste generation and resource depletion. Identifying potential household waste for reuse and recycling as secondary raw materials has emerged as a key technique for addressing these environmental concerns. This study uses the Colombo municipality in Sri Lanka to identify and evaluate household waste products having the potential to be reused as secondary raw materials in the construction sector. The study employs a mixed method for data collection and analysis. First, a questionnaire survey of industry experts was conducted to identify and assess the requirements for household waste that may be utilized in the construction sector, followed by a complete literature analysis to determine the reuse applications of potential household waste. The findings of this study will be useful in identifying and evaluating household waste items that may be recycled as secondary raw materials in the construction sector. It would also help to establish sustainable waste management techniques and circular economy practices in Sri Lanka. The study’s findings can help policymakers, waste management authorities, and stakeholders in the construction industry to implement effective waste management practices and promote the use of recycled materials in construction projects, reducing environmental impact and conserving natural resources.

The environmental agenda for the development of economic systems necessitates the formation of a market for secondary petrochemical products. A comparative analysis of the policies of sustainable development of petrochemical companies showed that the policy of sustainable development of individual budinesses is currently focused on the use of the following tools: development of the product portfolio, participation in international initiatives, partnerships and forums; voluntary industry initiatives and private projects to implement the first steps towards the collective goals of sustainable development. Among the main solutions of the reviewed organisations are products made of renewable raw materials and recyclable products. At the same time, the implementation of the responsible production and consumption by petrochemical companies is limited by the production and technological solutions of manufacturers of consumer goods. Environmentally unsustainable use of polymers by such enterprises makes their recycling difficult and limits the implementation of the concept of circular economy in petrochemicals. The article identifies key problems in the management and use of secondary resources: underdeveloped waste market conditions; uneven scale and geography of waste; inconsistent and inefficient (unsystematic) measures of waste market regulation, difficulties in forecasting prices for key raw materials and building a pricing mechanism in key markets, which are represented by polyethylene terephthalates, high density polyethylene, low density polyethylene and polypropylene. The introduction of chemolysis into the well-established technological processes of oil and gas chemical companies to work with secondary polymers requires an assessment of the acceptable level of risk. The needs of the market on the part of customers are not fully formed, so the dynamic changes, creating difficulties for petrochemical companies. Most of the highlighted problems are typical for both Russian and global markets of secondary petrochemicals. At the same time, the features of state regulation and logistics services for secondary petrochemical products are regional in nature, therefore, they are considered in the work for the conditions of the Russian Federation.