Waste Recovery Research Articles

Real-time gas phase monitoring of regulated emissions from a waste recovery center by terahertz rotational spectroscopy

This research proposes a practical method for extracting zinc from leaching residues at ALZINC Ghazaouet - Tlemcen (Algeria), which can improve the yield of waste recovery during the wet treatment of zinc ore. The quality of the blende and calcine (grilled) in terms of elemental chemical composition was identified using X-ray fluorescence (XRF) and residues containing 20.02 wt% Zn and 20.24 wt% Fe were determined by volumetric analysis. The experimental protocol was established in two successive stages in order to optimise the operating conditions of the ammonium salt-based jarosite process. The best process yield with 17.02% zinc recovery from residues was obtained under operating conditions of pH 1.5 (190g/L H2SO4), a temperature of 90°C, 800mg of (NH4)2SO4 and a reaction time of 300min. The microstructure and elemental distribution of the materials studied were examined using a scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS) and mapping. A qualitative analysis of the samples was performed using X-ray diffraction (XRD). This analysis, combined with Rietveld refinement, confirmed the effectiveness of the treatment thanks to the quality of the obtained product (Zinc), with a purity of 99.995% and an estimated average grain size of 11μm.

This study aims to evaluate the environmental performance of G7 countries using the Environmental Performance Index. To do this, we introduce a novel ranking multi-criteria method, Alternative Prioritization and Assessment System, for the first time in the literature. It offers a useful contribution to the multi-criteria decision-making field by tackling several ranking problems, such as low interpretability, a lack of dual evaluation metrics, and limited flexibility in data-driven scenarios. Moreover, three advanced multi-criteria decision-making weighting methods are used to assign weights to the environmental performance criteria. Therefore, the proposed Alternative Prioritization and Assessment System-based methodology evaluates the environmental performance of G7 countries in reaching sustainable development goals. The results show that the waste recovery rate is the paramount indicator, while unsafe drinking water has the least significance. Germany is ranked as the top-performing country, while Japan is ranked lowest. The key contribution of this research lies in the development and implementation of the Alternative Prioritization and Assessment System method, offering enhanced ranking stability, transparency, and dual-perspective evaluation. The use of the Environmental Performance Index further supports replicability and policy relevance. The proposed model can guide environmental policy formulation and benchmarking efforts among industrialized nations. It also provides a robust framework for cross-national sustainability comparisons in future research.

The shift from linear to circular economy systems is critical for sustainable water and nutrient management, particularly in developing countries such as Ghana. This paper explores governance models shaping the implementation of circular economy principles, state-regulated, collaborative, public-private, community-based, and adaptive, through a systematic review of peer-reviewed literature published between 2018 and 2025. The review was conducted using databases such as Scopus, Web of Science, and Google Scholar, applying inclusion criteria focused on governance frameworks in circular economy transitions. Findings reveal that state-regulated frameworks, including Ghana’s National Plastics Management Policy and Circular Economy Roadmap, provide essential direction but face weak enforcement and limited financing. Collaborative platforms like the Waste Recovery Platform and Circular Bio-Economy Innovation Hub foster innovation but require long-term financial sustainability. Public-private partnerships mobilize investment but risk political interference and limited transparency, while community-led initiatives enhance legitimacy but often lack safety and technical integration with formal systems. Adaptive governance emerges as the most promising model, offering flexibility through integrated tools and monitoring mechanisms. The paper concludes that Ghana’s transition to a circular economy will require stronger state enforcement, sustainable financing mechanisms for collaborative platforms, transparent regulatory safeguards for public-private projects, formal recognition and training for community actors, and the adoption of adaptive monitoring frameworks. These targeted recommendations strengthen the policy and institutional pathways for sustainable resource management in Ghana.

This study examines the environmental and economic benefits of waste recovery in steel plants using life cycle assessment (LCA), metallurgical analysis, and economic feasibility studies. The LCA, conducted with GaBi software, indicates that recycled steel reduces carbon dioxide emissions by 80%, energy consumption by 70%, and water usage by 60% compared to virgin steel. Waste recovery assessment identified key recyclable fractions from steel melting shops, blooming mills, and rolling mills. A comparative analysis with virgin steel, aluminium, and copper indicates that recycled steel has the lowest carbon footprint and exhibits superior recycling efficiency, particularly in well-managed industrial processes using electric arc furnace technology. The techno-economic study demonstrated 40% cost savings in material procurement, with a return on investment under two years and an internal rate of return of 35%. Long-term durability studies confirmed that recycled T22-grade steel maintains its structural integrity, fatigue strength, and corrosion resistance over time. These findings support global sustainability targets, including the Paris Agreement and India’s National Steel Policy, and highlight the role of artificial intelligence, blockchain, and predictive analytics in optimising waste recovery. This study reinforces the potential of sustainable steel manufacturing to enhance cost efficiency, reduce emissions, and promote circular economy practices.

Breaking the calcium paradigm: Sodium-mediated thermochemical synergy for low-temperature melting and enhanced metal solidification.

Effectiveness and mechanism of in situ sludge biochar carrier enhancing salt-tolerant bacteria for pyrazolone degradation in high-salinity pharmaceutical wastewater.

Effective recovery of materials from construction and demolition waste (CDW) remains a major problem and a real challenge in terms of implementing the circular economy. In many countries, this waste is landfilled due to the lack of modern technological lines for its recovery and recycling, including the sorting of materials suitable for reuse. Understanding the environmental impact of the CDW treatment process is important as it constitutes the final stage of building life cycle assessment and the basis for eco-design of construction processes. In addition, the recovered materials can be used as raw materials for construction, thereby closing the waste loop and aligning with the circular economy concept. The purpose of this study is to compare the environmental impact of three different CDW recovery technologies in order to identify the optimal option. The analysis was performed using the life cycle assessment (LCA) methodology, SimaPro 8.1 software, and the Ecoinvent v3.8 database. 1 Mg of processed CDW was adopted as the functional unit. It was found that the process of recovering materials from CDW allows for sorting over 13% of materials for recycling and approx. 40% of raw materials for reuse (stone aggregates). The conducted analyses showed that all three installations exert a negative impact on the environment. Solution No. 2 had the lowest total environmental impact (15.96 Pt) under the assumptions and datasets used in this study, presenting average electricity and fuel consumption and average weight of sorted materials for recycling. Installation No. 3, which sorts the largest volume of materials for recycling, also used the most electricity; therefore, it could not be considered as the solution with the minimal overall environmental impact. The research revealed that the treatment of CDW in a crusher, applied at all installations, is the process stage resulting in the greatest environmental pressure (16.92 Pt). The high level of sorted recyclable waste enabled a relatively low carbon footprint for processes No. 2 and No. 3, 18.7 and 17.6 kg CO2 eq, respectively (more than four times lower than for installation No. 1). Future analyses should focus on optimizing the CDW recovery process by avoiding the use of impact crushers, as adding more waste sorting equipment does not significantly enhance environmental benefits.

ABSTRACTA methodology for the radiological characterization of organic radioactive liquid wastes (OLRWS) adsorbed into soils, generated in the 80s and 1990s is developed to define their management. The methodology is based on the recovery of radioactive organic liquids from their solid matrix using a solvent and their subsequent quantification. It is established on the basis of controlled tests with samples prepared with radioactive scintillation liquids mixed with soil, using different scintillation liquids, solvents, radionuclides and process types (percolation or batch). Thinner is selected as the extraction agent because it is inexpensive, easily accessible and offers good performance in the removal of radioactive organic liquids from soil. The recovery of the scintillation liquids depends mainly on their miscibility with the solvent and the affinity of the radionuclides to the soil. The method was applied to OLRWS containing only H‐3 with average activities of 39 Bq g−1 and can therefore be released from regulatory control.

Purpose This study was conducted to investigate the influence of school characteristics and meal policies on share table eligible (STE) milk waste (i.e. unopened cartons of milk waste) and estimate the environmental and economic benefits of utilizing share tables (STs) to recover milk waste. Design/methodology/approach Data from the School Nutrition and Meal Cost Study (SNMCS) on student plate waste in 170 schools were used. Tobit regression models were applied to estimate the drivers of STE milk waste and predict annual STE milk waste in the National School Lunch Program (NSLP). Greenhouse gas (GHG) emissions, water footprint, and food cost associated with STE milk waste were also estimated. Findings Universal free lunch, open campus, students being allowed to leave the cafeteria early for recess, lunch participation rate, and school location (urban vs. rural) were significant drivers of STE milk waste in the NSLP. Should STs be enforced nationwide, NSLP participating schools could recover over 13% of milk servings or 620 million cartons of milk, reduce GHG emissions by 187 thousand MT of CO2-eq, reduce water footprint by 13 billion liters, and save up to US$118 million in meal expenditures per year. Practical implications This study supports the growing evidence that STs can help school meal programs reduce environmental degradation, address high and rising meal debts, and fight food insecurity. Originality/value This is the first study to examine the drivers of STE milk waste and estimate the environmental and economic impacts of STE milk waste.

Sulfur modification enhances promotion of carbon-iron composites on carbon chain elongation.

Hyperspectral imaging for real-time waste materials characterization and recovery using endmember extraction and abundance detection

Enhancing sorting efficiency in cluttered construction and demolition waste streams via boundary-guided grasp detection.

Short-acidification process for lithium extraction from lepidolite with near-zero waste and full-component recovery

Carbon-based and iron-based materials have been widely reported as effective promoters in biogas fermentation due to the promotion of electron transport. However, the effect of these materials, especially in combination, on short-chain fatty acids (SCFAs) production has been scarcely reported. In this study, the production of short-chain fatty acids (SCFAs) from green cabbage waste was promoted by adding biochar (BC) and biochar-supported zero-valent iron (BC@ZVI). The underlying mechanisms, focusing on metabolic pathways and electron transport, were subsequently investigated through metagenomic analysis. The optimal SCFAs yields were achieved with BC (5 g·L⁻1) and BC@ZVI (15 g·L⁻1). While BC notably enhanced n-butyrate production (89.4-fold), BC@ZVI balancedly promoted acetate and n-butyrate. Metagenomics revealed that BC@ZVI's superiority stemmed from its enhanced ability to enrich functional microbes and facilitate electron transfer. Metagenomic analysis revealed that BC@ZVI enriched Sphaerochaeta and Herbinix, which could participate in the direct interspecies electron transfer process. The abundance of almost all functional enzymes involved in carbohydrate hydrolysis and the synthesis of acetate and n-butyrate were remarkably increased by BC@ZVI. BC and BC@ZVI lead to a notable enrichment of conductive pili genes, including pilB, pilC, and pilM. BC@ZVI enriched both conductive pili and c-type cytochromes, which could be considered a more effective selection than BC. Notably, BC@ZVI was more effective than BC in stimulating n-butyrate-type fermentation, significantly shortening the lag phase and the overall fermentation cycle, thereby exhibiting better comprehensive performance, enhancing pH buffering capacity, and strengthening electron transfer and substrate hydrolysis. The results proved the potential of BC@ZVI in SCFAs fermentation and deciphered the underlying mechanisms, which provided a new perspective to promote resource recovery of organic waste by anaerobic system.

The research method is a comprehensive assessment of the environmental performance of transnational corporations in 2020–2024 through the prism of a reduction in greenhouse gas emissions and an increase in resource efficiency, close attention to the spheres of recovery of recovered energy, repeated water recovery and recycling of waste. Particular attention is paid to identifying the dynamics of change in corporate strategic approaches to managing the carbon footprint and integrating the principles of steel development and the circular economy. The methodological basis for the investigation is a thorough and clear analysis of the corporate non-financial information of leading transnational corporations. Vicorista methods: regular analysis – to assess the dynamics of key environmental indicators (Scope 1, Scope 2, Scope 3, water recycling, waste recycling, energy recovery); structural-dynamic analysis – to identify trends and patterns in changes in indicators; an indicative approach – to determine the level of environmental performance of other corporations and the leveling of their strategies; system approach - to integrate the results into a single model for assessing environmental performance. The article presents a systematic analysis of the environmental responsibility of leading multinational corporations in 2020–2024 using an integrated approach to assessing greenhouse gas emissions, sustainable resource use, and the integration of circular economy principles. Direct (Scope 1), indirect, related to the consumption of purchased energy (Scope 2 – location-based and market-based), as well as indirect emissions in value chains (Scope 3) were investigated. Particular attention is paid to key environmental indicators: the share of renewable energy, the volume of water reuse, and the level of waste recycling, which allows assessing the comprehensive effectiveness of the corporate environmental strategy. Based on the analysis of data from 11 international corporations (Apple Inc., Nvidia Corp., Microsoft Corp., Cisco Systems Inc., Procter & Gamble, Johnson & Johnson, Pfizer Inc., Amgen Inc., Ecolab Inc., Caterpillar Inc., CRH.), both progressive practices of decarbonization and resource management were identified, as well as problematic aspects, including high indirect emissions, unstable water use and fluctuations in waste recycling rates. The study demonstrates the relationship between scientifically based climate goal setting and their implementation in corporate practice, identifies leaders in environmental efficiency and provides an empirical basis for developing strategies to reduce carbon footprint, integrate circular approaches and increase the resilience of business processes. The results obtained have practical significance for the formation of corporate sustainable development policies and the alignment of corporate strategies with global climate initiatives.

Regional industrial symbiosis networks for waste minimisation: a case study from Italy.

Food waste has the potential for transformation into value-added products as a sustainable strategy for diverting waste from landfills in South Africa. This study uses a social cost–benefit framework to evaluate various waste conversion technologies, including anaerobic digestion, aerobic composting, vermicomposting, and black soldier fly larvae, within South Africa's unique socio-economic and environmental landscape. Quantitative waste composition analyses are combined with technology evaluations, revealing significant costs for landfilling, the current status quo, and underscoring the economic and environmental urgency of strategic food waste diversion. Highlighting gate fees’ critical role, the findings advocate adjusting these fees to reflect true environmental costs and incentivise alternatives. Notably, black soldier fly larvae and vermicomposting technologies emerge as dual-benefit strategies for waste reduction and resource recovery. Policy and infrastructure advancements are recommended to enable the broad adoption of these technologies, emphasising their importance in achieving sustainability and economic objectives.

Frass-the main by-product of insect rearing for animal feed-is emerging as a promising soil amendment and plant growth promoter. However, basic agronomic information is lacking and prevents frass' widespread use as a biofertilizer. This study assessed impacts of black soldier fly (Hermetia illucens L. [Diptera: Stratiomyidae]) frass on soil fertility, crop growth, and quality compared to poultry litter (PL). Irrigated and non-irrigated soybean (Glycine max L. Merr.) and non-irrigated switchgrass (Panicum virgatum L.) plots received either PL (5.6 Mg ha-1), low frass rate (LF; 5.6 Mg ha-1), high frass rate (HF; 11.2 Mg ha-1), besides the unamended control (CT). In general, soil nutrients and enzymes at the soil surface (0-15cm) were unaffected by soil amendments. Irrigated-HF soybean had 7% higher grain P concentration than non-irrigated-HF, and 13% greater P concentration than the non-irrigated CT. Additionally, HF increased K concentration in switchgrass by 25% relative to the CT. HF reduced soybean leaf damage by 35% and 48% relative to the non-irrigated CT and PL-irrigated plots, illustrating for the first time frass' potential to enhance plant resistance to herbivory, likely owing to the presence of chitin. LF had 2-4 times greater nutrient use efficiency than HF and PL in organic soybean and switchgrass systems, reflective of similar yields despite lower nutrient inputs. These findings provide foundational knowledge for frass utilization as an organic fertilizer and biostimulant, closing nutrient loops through waste recovery during insect rearing, and supporting the development of an emerging sustainable industry.

The use of highly flammable materials such as foams, resins, and plastics has led to an increase in the frequency and severity of urban fires worldwide. To address this issue, this study developed a high-specific-surface-area mesoporous metal-organic framework (Fe-MOFs) with heat trapping and smoke adsorption. The Fe-MOFs, zinc tailings (ZTs), piperazine pyrophosphate (PAPP), and sodium lignosulfonate (LS) were used to modify rigid polyurethane foam (RPUF). Cone calorimeter combustion experiments showed that Fe-MOFs significantly reduced the heat release and smoke emission of RPUF through heat trapping and smoke adsorption. Compared to pure RPUF, the peak heat release rate (p-HRR) and total heat release rate (THR) of Fe-2 decreased by 64.5% and 68.6%, respectively, and the total smoke production (TSP) of Fe-5 decreased by 55.6%. Vertical combustion experiments showed that all RPUF achieved UL-94 V-0 rating. Thermogravimetric analysis, pyrolysis kinetics, and thermogravimetry-infrared indicated that Fe-MOFs protected RPUF during the main decomposition stage (301-446 °C) and enhanced its thermal stability by accelerating the decomposition of PAPP and LS. Residual carbon analysis revealed that the appropriate amount of Fe-MOFs helped form the solid, dense, continuous, and stable carbon layer. This carbon layer hindered flame and heat transfer and limited heat and smoke release. Physical property tests showed that Fe-MOFs affected the foaming process of RPUF. This led to increased density and compressive strength of RPUF. Compared to pure RPUF, the compressive strength of Fe-2 increased from 0.147 to 0.281 MPa. These results indicated that Fe-MOFs help to enhance the performance of RPUF. This study provides an efficient solution for the recovery of solid waste and the development of fire-resistant polymer composites.