Pawan Chapagaee, Sandesh Thapa, Sushil Shrestha
et al.
Organic waste accumulation poses a significant environmental challenge, necessitating effective waste management strategies. The black soldier fly serves as a beneficial insect, aiding in waste reduction and animal feed production, while its frass contributes to sustainable soil improvement. Therefore, this study is aimed to investigate the bioconversion efficiency, growth performance, longevity, waste reduction, and nutritional composition of Hermetia illucens (Black soldier fly; BSF) larvae reared on five different urban organic wastes: restaurant waste, vegetable waste, fruit waste, kitchen waste, and butchery chicken waste following completely randomized design (CRD) with five urban waste treatment and four replications. The results revealed the highest larval growth rate and bioconversion found on restaurant waste 12.02 ± 0.47 mg/day and 6.97 ± 0.15 % respectively. Larva reared on butchery chicken waste showed highest larval mortality (76.02 ± 0.42 %) and life cycle duration (57 days). Also, the highest decomposition rate of waste was found on kitchen waste (0.73 ± 0.02) and fruit waste (0.72 ± 0.009). The highest waste reduction rate was found on kitchen waste (73.66 ± 2.70 %) and restaurant waste (62 ± 0.94 %). Larvae reared on restaurant waste exhibited highest crude protein content (37 ± 0.44 %DM), whereas highest crude fat was found on larva reared on butchery chicken waste (47.4 ± 0.64 %DM). The study highlights how BSF can efficiently decrease waste quantities and transform nutrient-balanced urban organic wastes into high-value biomass. The most promising substrates for large-scale BSF rearing and circular bio economy applications in developing nations like Nepal were found to be kitchen and restaurant wastes.
Kassé Jean Hugues Angbé, Dennis Krüger, Volker Lenz
et al.
West Africa is a key player in cocoa cultivation, accounting for approximately 70% of world cocoa bean production. However, cocoa pod husk (CPH), an important by-product, remains largely underutilized. Therefore, this study provides the first comprehensive, multi-country assessment of CPH generation across seven major West African cocoa-producing countries namely Côte d'Ivoire, Ghana, Nigeria, Sierra Leone, Liberia, Guinea, and Togo over a 20-year period. It further assesses current management pathways and their environmental implications, with an evaluation of biochar as valorization approach. The data used in this study was gathered through field surveys and quantitative secondary data from FAOSTAT. Methane (CH4) emissions from decomposition of CPH were estimated based on IPCC methodologies, while biochar potential and carbon sequestration capacity were determined using established equations. The results showed that in 20 years, a total of 578 million tonnes of CPH were produced, with Côte d'Ivoire contributing the largest share with 331 million tonnes, followed by Ghana with 160 million tonnes. At present, on-farm abandonment remains the predominant management practice, emitting an estimated 17 million tonnes of carbon dioxide equivalent (CO2-eq) annually representing about 3% of Africa’s agricultural CH4 emissions. Conversion of this biomass into biochar represents a significant mitigation opportunity. The estimated annual production potential of CPH-biochar is 869 thousand tonnes, capable of sequestering about 1.59 million tonnes of CO2-eq per year. Adopting this approach could reduce greenhouse gas (GHG) emissions more than 18 million tonnes of CO2-eq, including avoided emissions and carbon sequestration. These findings highlight the importance of CPH-biochar production as a promising strategy for sustainable waste management.
The increasing demand for sustainable radiation shielding solutions has prompted a transition from traditional materials such as lead and cement-based concrete towards environmentally friendly alternatives. Despite their effectiveness in radiation shielding, traditional shielding concrete faces challenges such as toxicity, high cost and environmental degradation. This literature review examines the potential of agricultural waste materials (AWMs) as partial substitutes in cement-based concrete composites for radiation shielding applications. Agricultural residues such as rice husk, sugarcane bagasse and coconut shell exhibit pozzolanic properties and offer mechanical benefits, improved durability and enhanced radiation attenuation capabilities. The article examines the key physical and chemical properties of various AWMs, highlighting their potential to improve concrete strength and shielding performance against gamma and neutron radiation. In addition to mechanical and shielding characteristics, the environmental and economic ramifications of AWM reuse are evaluated, including reductions in carbon footprint and waste management benefits. The article also identifies challenges like standardization issues and the requirements for long-term durability data, highlighting how AWM-integrated concrete can be a feasible, cost-effective and sustainable solution for contemporary radiation shielding, supporting the objectives of the circular economy and green building.
Municipal solid waste incineration (MSWI) fly ash contains high levels of soluble chlorides and exhibits strong heavy-metal leachability; therefore, conventional treatment routes rely on pre-washing. This study proposes an integrated pathway combining no-wash chlorine retention, staged thermal recovery of heavy metals, and ambient-cooled vitrification, coordinated through a network-breaking index (NBI). This approach eliminates the need for washing, thereby reducing water consumption and simplifying the treatment of chlorine-containing solid waste. Blends of municipal and coal fly ash (C30-C50, where Cx denotes x wt.% coal fly ash) were heated to 1200 °C for 1 h and cooled under ambient air. X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and BCR sequential extraction were performed to resolve the relationships among phase evolution, glass-network structure, and environmental performance. The results show that a mid-range NBI (0.67-0.97) provides both low-temperature fusibility and robust network formation. C40-C45 achieved near-complete vitrification (∼99.9%). Under identical conditions, metal volatilization followed the order Pb/Cd > Cu > Zn > Cr. Mechanistically, thin NaCl/KCl salt films first lowered the mass-transfer barriers, and a continuous melt subsequently developed and polymerized. FTIR revealed depolymerization from C35-C40, followed by re-polymerization from C40-C45, which strongly correlated with K/Na release, indicating shared composition-process controls. These findings guided a temperature-zoned recovery strategy-800-900 °C for Pb/Cd, 900-1100 °C for Cu, and 1150-1200 °C for Zn-followed by vitrification at 1200 °C and ambient cooling to immobilize low-volatility species (e.g., Cr). This method minimizes preprocessing, reduces secondary pollution, and offers a promising route for Ca- and Cl-rich hazardous fly ash.
This systematic review examines food waste management in Malaysian private healthcare, investigating the complex intersection of operational inefficiencies and deeply rooted cultural practices. Traditional quantification methods inadequately address cultural drivers such as kenduri hospitality traditions and halal compliance requirements, creating systematic gaps in management approaches within Malaysian healthcare contexts. A systematic review of 34 studies was conducted examining food waste quantification, cultural factors, and technological solutions in Malaysian private hospitals. This review synthesized evidence from 1832 initial records, achieving high methodological rigour with 85% of studies meeting quality standards. Data extraction focused on waste rates, cultural drivers, and regional management strategies from ASEAN countries, analyzed through socio-technical systems theory. Oncology wards demonstrated highest waste rates at 59.3% due to cultural-therapeutic diet mismatches. Kenduri traditions contributed to 62% systematic overproduction, while 41% of halal-compliant surplus became ineligible for redistribution due to improper segregation. Artificial intelligence (AI)-driven portion control achieved 89% prediction accuracy but faced implementation resistance. Regional analysis revealed Thailand's stream-specific audits achieved 37% waste reduction through cultural-operational categorization, complemented by Indonesia's halal-compliant composting approaches. Study limitations include English-language restriction and reliance on secondary data. Malaysian private healthcare requires culturally-adaptive waste management frameworks integrating traditional values with operational efficiency. Technology integration combining AI portion control with blockchain halal traceability offers scalable solutions when implemented alongside stakeholder-driven standardization. These findings provide the first comprehensive framework for culturally-adaptive waste management in Islamic healthcare contexts.
ABSTRACT The rapid urbanization and industrialization in China have significantly increased municipal solid waste (MSW) generation, with incineration emerging as the dominant treatment method. However, this process produces substantial quantities of MSW incineration fly ash (MSWI-FA) and bottom ash (BA), posing environmental risks due to heavy metals, dioxins, and soluble salts. This review consolidates recent advancements in recycling these byproducts into construction materials, addressing technical feasibility, environmental impacts, and policy challenges. A systematic literature analysis (2000–2024) was conducted using Web of Science and China National Knowledge Infrastructure, supplemented by bibliometric analysis via CiteSpace. MSWI-FA is classified as hazardous waste, requiring stabilization via chemical agents (e.g. Na2HPO4/Na2S) or thermal treatments (e.g. vitrification at 1000–1500°C) to immobilize contaminants. In contrast, BA, which is generally classified as non-hazardous, is evaluated as a direct replacement for both fine and coarse natural aggregates in construction, with its geotechnical properties making it suitable for applications in concrete (≤50% substitution), road bases, and as a raw material in ceramics (20–50% substitution). Key applications include cement kiln co-processing, microcrystalline glass production, and geopolymer-stabilized road bases. Despite progress, challenges persist: compositional variability, high pretreatment costs (1,500–3,500 CNY/ton for vitrification), and insufficient long-term leaching data ( > 10 years). Policy gaps, such as outdated leaching standards (GB 5085.3-2007) and limited economic incentives, further hinder scalability. The review underscores the dual benefits of reducing landfill reliance and conserving natural resources, aligning with China’s circular economy goals. Future efforts should prioritize hybrid stabilization technologies, lifecycle assessments, and standardized protocols to enhance industrial adoption. By addressing these barriers, MSWI-FA and BA can transition from environmental liabilities to sustainable construction resources, supporting China’s waste management and decarbonization targets. Implications: Municipal solid waste incineration (MSWI) fly ash (FA) and bottom ash (BA) are environmental liabilities with resource potential in construction. Hazardous FA requires rigorous stabilization to immobilize heavy metals and dioxins, while non-hazardous BA is a viable substitute for natural aggregates. Widespread adoption is hindered by compositional variability, high pre-treatment costs (1,500–3,500 CNY/ton for FA vitrification), insufficient long-term leaching data, and outdated standards (GB 5085.3-2007). Developing hybrid stabilization technologies and lifecycle-based policies is crucial to transform these ashes into sustainable construction materials, aligning with circular economy and decarbonization goals.
Background: The construction sector significantly contributes to global CO₂ emissions, primarily from Portland cement production, accounting for about 8% of total emissions. This study explores the environmental, economic, and social potential of industrial waste-based geopolymers as a sustainable alternative to conventional concrete, supporting the Net Zero Emission 2050 target. Methods: This research adopts a qualitative literature review approach, collecting and analyzing recent studies concerning the utilization of fly ash, slag, silica fume, and waste glass as binding precursors in geopolymer synthesis. Furthermore, a comparative analysis was conducted to assess the potential for CO₂ emission reduction and cost efficiency based on several implemented projects. Findings: The findings indicate that geopolymer concrete can reduce CO₂ emissions by approximately 18%–64% and production costs by up to 30%, while maintaining comparable mechanical performance and durability to Portland cement-based concrete. Large-scale applications in several countries have demonstrated the material’s practical feasibility. From an environmental perspective, geopolymer technology substantially decreases embodied carbon; economically, it lowers maintenance expenses; and socially, it promotes green employment opportunities and enhances public awareness of sustainable construction practices. Nevertheless, the lack of standardized regulations and limited policy support remain key barriers to its broader implementation. Conclusion: Geopolymer technology demonstrates significant potential in achieving sustainable and low-carbon construction, thereby contributing to the realization of the Net Zero Emission 2050 goal. Novelty/originality of this article: The novelty of this study lies in its comprehensive integration of various industrial waste materials to holistically assess their environmental, economic, and social benefits as a unified approach toward sustainable construction.
Efficient thermal conversion of municipal solid waste (MSW) requires a mechanistic understanding of real, heterogeneous waste, yet most mechanistic studies rely on simplified or simulated MSW, leaving the molecular-level impacts of real heterogeneity insufficiently understood. This study aims to systematically characterize pyrolysis of real MSW fractions and evaluate the influence of sample- and temporal-scale heterogeneity. Two MSW samples were collected from an incineration plant on the same day (morning vs. afternoon), classified and cryogenically milled to assess achievable laboratory homogeneity and temporal heterogeneity. Pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) was conducted based on thermogravimetric profiles. Principal component analysis (PCA) was applied on the results to jointly distinguish MSW fractions and quantify heterogeneity effect via distances in principal-component space. PCA revealed a distance pattern of technical replicates < inter-batch < inter-fraction, confirming sufficient homogenization by cryogenic milling and detectable temporal variability in real MSW. Real MSW predominantly produced hydroxyacetaldehyde and levoglucosan from biomass-based fractions (Paper, Cloth, Wood, Kitchen Waste) and styrene from Resin. These differed from those reported for simulated MSW, e.g., acetic acid (sawdust), D-allose (cotton clothes), acetic acid (vegetables), underscoring the importance of using real MSW in mechanistic investigations. Increasing temperature shifted biomass volatiles from anhydrosugars toward carbonyls and gases, while Resin evolved from benzene and straight-chain compounds to cyclic species. The PCA-based distance framework in this study provides a methodological approach for quantifying heterogeneity, assessing representativeness, and improving the reliability of lab micro-scale analyses of real MSW.
Addressing the dual challenges of food waste management and sustainable protein production requires circular economy solutions. This study demonstrates a sustainable approach to convert restaurant food waste (FW) into a protein-rich feed ingredient using black soldier fly (BSF) larvae. The nutritional profile of the FW-derived BSF meal was evaluated and compared to soybean meal (SBM). BSF meal had higher digestible (20.08 MJ/kg) and metabolizable (18.74 MJ/kg) energy than SBM (P < 0.01). The standardized ileal digestibility of amino acids in BSF meal (78.90%-85.12%) was comparable to or better than that of SBM. In the subsequent experiment, 72 pigs were assigned to either a control diet (Ctrl) or an experimental diet (BSF) with 20% SBM replaced by BSF meal. Throughout the trial, the BSF group showed a 5.80% higher average daily gain (P = 0.06) and a 4.29% higher average daily feed intake (P < 0.05). BSF meal increased shoulder backfat thickness and muscle decanoic acid content by 26.68% and 83.33%, respectively (P < 0.05). Furthermore, BSF meal improved lipid metabolism and antioxidant status, as characterized by reduced serum total cholesterol and malondialdehyde levels, and up-regulation of myosin heavy chain I expression (P < 0.05). BSF meal modulated the gut microbiota by enriching taxa linked to improved meat quality and health, including Clostridium_sensu_stricto_1 (1.97-fold) and Clostridiaceae (1.94-fold) (P < 0.05). In conclusion, BSF-based bioconversion effectively transformed FW into a sustainable, high-performance feed ingredient that enhanced pig productivity and meat quality, thereby contributing to a more circular and resilient food system.
The rhizosphere microbiome, as the ‘second genome’ of plants, greatly extends the ability of plants to cope with various biotic and abiotic stresses. Organic amendments have also been demonstrated to elevate the tolerance of plants to salt-stress. However, the interlinking between rhizosphere microbiome, plant tolerance to salt-stress, and organic amendments remains unclear. Herein, two halotolerant microbial consortia (H1 and H2) expedited the composting process without affecting the quality of the resulting composts. Interestingly, both bio-composts (C-H1 and C-H2), especially C-H1, greatly improved the growth and photosynthetic ability of tomato under salt-stress by 25.63 % to 56.0 %. The levels of superoxide dismutase, peroxidase and catalase activities, and the content of malondialdehyde in tomato by C-H1 were 67.6 %, 76.9 %, 137.4 %, and 276.3 % higher, respectively, than those by the control compost (C). The 16S rRNA profiling analysis revealed that compost fertilization shifted the microbial community in the tomato rhizosphere, leading to a consistent enrichment of Luteimonas and a transient enrichment of Conexibacter, Solirubrobacter, Lactobacillus, and Ureibacillus, especially C-H1. In vitro analysis further confirmed that a Luteimonas bacterium which was over-represent in the rhizosphere of bio-compost-fertilized tomatoes promoted the growth of root by 29.9 % and 15.8 % at 0.4 % and 0.8 % NaCl, respectively. In conclusion, bio-compost could improve salt tolerance of tomato by stimulating the expression of salt-tolerance-related enzymes and recruiting beneficial Luteimonas spp.
The ever-increasing abundance and expanding affordances of plastics have come to instantiate modernity through their successes and failures in usage and beyond. Materially, plastics have a capacity to stubbornly endure yet simultaneously to fracture. Grounded in ethnographic fieldwork on an Indian Ocean island, this article will explore the heritage of plastic objects in their shattering and dispersal. The novel presence and ubiquity of plastics have caused some scholars to propose that the presence of plastics could constitute a possible marker of the Anthropocene. Yet plastics won’t stay in their own epoch. Microplastics can migrate and infuse sedimentary layers from previous eras, shimmying down to earlier stratigraphic layers and complicating the very knowability of the past. This paper will look at the temporal vertiginousness of the current epoch through the recalcitrance of human-made materials, arguing that, even in their material remnants, plastics radically complicate the delineation and understanding of geological time.
Municipal refuse. Solid wastes, Standardization. Simplification. Waste
Akshata Pattanshetti, Vidhya Jadhav, Amruta Koli
et al.
The efficient CO2 capture requires engineering a low-cost, highly efficient adsorbent. Herein, the upcycling of waste floral foam into chemically activated nanoporous carbon (CANC) is reported. The implications of the impregnation ratio of KOH on the porosity, surface functionality of CANC, and its role in CO2 capture are examined and discussed. The optimized sample, CANC-2 (SSA 1043 m2/g), with a large ultra-micropore volume and higher oxygen and nitrogen content, demonstrates 3.71 mmol/g CO2 capture capacity at 15 ℃ and 1 atm. The framework provided here offers a technique for tuning the attributes of nanoporous carbon favorable for CO2 capture. Ultimately, the pollution control of solid polymeric waste can be done by upcycling it into value-added products which further utilized in environmental applications.
Numerous studies have reported the presence of microplastics (MPs) in waste collection and disposal systems. However, current scientific studies on measuring MP occurrence in a waste management context are not comparable due to a lack of standardized methodologies. Consequently, the impact of MPs on ecosystems and human health remains largely unclear. To address the inconsistencies, present in published studies, this review thoroughly examines sample preparation techniques for transfer stations, landfill leachate, recycling, compost, and incineration ash samples. Furthermore, various analytical approaches such as flotation, filtration, and organic matter digestion, as well as morphological categorization, identification, and quantification, are subsequently rigorously assessed. The benefits and limitations of each methodology are evaluated to facilitate the development of accurate and effective methods for detecting and characterizing nanoplastics. Recent research suggests that plastic recycling and composting facilities are the primary environmental sources of microplastic pollution among different waste treatment methods. The most prevalent microplastic types discovered in waste management were polyethylene (PE) and polypropylene (PP), with fragment and fiber being the most frequently reported morphologies. The review highlights a number of tactics that could be integrated into the methodology development for detecting microplastics in waste management systems (WMS), ultimately leading to better consistency and reliability of data across different studies. In essence, this will advance our comprehension of potential risks associated with microplastics.
ABSTRACT Efficient solid waste management is crucial for urban health and welfare in the midst of fast industrialization and urbanization. In this changing environment, government authorities have a significant role in addressing and reducing the effects of solid waste. While waste separation at the source simplifies processes, manual sorting is a consequence of ignorance in numerous regions, which endangers the health of waste pickers. This study addresses the challenges by introducing the MSW-Net model, a hierarchical stacking model designed for the automated classification of municipal solid waste (MSW). Customized Convolutional Neural Network (custom CNN) and Bayesian-Optimized MobileNet models serve as the base models, with Gradient Boosting employed as the meta-classifier. The MSW-Net model, as proposed, exhibits exceptional performance, attaining 99%, 95%, and 96.43% accuracy rates over training, validation, and testing, respectively. Additionally, the model achieves precision, recall, and F1 scores of 96.42%, 96.43%, and 96.42% during the testing phase. Therefore, the proposed MSW-Net model performs better than the other existing models in sorting the waste. This could also aid the municipal authorities in classifying the waste with minimal human intervention. Implications: The MSW-Net model, featuring a hierarchical stacking approach with custom CNN and Bayesian-Optimized MobileNet base models, and Gradient Boosting as the meta-classifier, achieves remarkable accuracy in automated municipal solid waste classification. With performance metrics of 99% accuracy in training, 95% in validation, and 96.43% in testing, alongside precision, recall, and F1 scores around 96.42%, the MSW-Net model significantly outperforms existing models. This advancement promises to aid municipal authorities in efficient waste management, reducing reliance on manual sorting and thereby improving the health and safety of waste pickers.
A material recovery facility (MRF) can transform municipal solid waste (MSW) into a valued commodity called refuse-derived fuel (RDF) as a promising solution to waste-to-energy conversion. The quality of the produced RDF significantly relies on the composition of in-feed waste and waste characterization method applied for auditing purposes, a process that is both time-consuming and fraught with potential hazards. This study focuses to enhance the workflow of the waste characterization process at an MRF. A solution named Smart Sight is proposed to detect and classify waste based on videos recorded after processing MSW through a mechanical sorting line consisting of bag breakers and trommel screens. A comprehensive dataset is created encompassing thirteen mixed waste classes from single and multi-family streams. The dataset is preprocessed with motion compensation techniques and frame differencing methods to extract and refine valuable frames. A one-stage YOLO detector model is then trained over the dataset. The experimental results show that the proposed method works efficiently at detecting and classifying waste objects in indoor MRF environments. Accuracy, precision, recall, and F1 score related to the proposed solution are found to be 0.70, 0.762, 0.69 and 0.72, respectively, with a mAP@0.5 of 0.716. The proposed approach is validated using data collected from local MRF by comparing the estimated waste composition values of the proposed solution with laboratory results obtained through current standardized industrial practices. Comparison reveals that waste characterization estimation obtained is consistent with the laboratory results, inferring that Smart-Sight is a viable tool for estimating waste composition.
AbstractThis study explores the effects of a policy intervention designed to simplify the standards for plastic waste separation on collection volume and the quality of recyclables. We employ a causal impact analysis based on a Bayesian structural time-series approach to estimate the effects of simplifying the municipal solid waste-separation process for plastic waste in Japan. We find that simplifying plastic waste-separation standards increases plastic packaging waste-collection volume. This effect seems to be largely driven by behavioral changes such as decreased time spent on waste separation. We also find that simplifying home separation increases the percentage of contaminated plastic packaging waste collected for recycling and other materials not subject to collection in the post-collection period. Several robustness and falsification tests corroborated these results. Our results highlight the importance of considering the trade-off between the quantity and quality of recyclables when designing plastic waste recycling policies.