From perception to action: Waste management challenges in Kassena Nankana East Municipality.

This study examines the perceptions and behaviours related to waste management (WM) among residents of the Kassena Nankana East Municipality in Ghana. A mixed-method approach was used to garner data from 394 household respondents, and the data was analysed using SPSS software. The findings reveal a weak correlation between educational attainment and effective waste management practices and a mildly positive correlation between waste awareness and the effectiveness of policies and legislation. Notably, a significant proportion of respondents preferred open burning (42.1 %) and dumping (18.8 %) as disposal methods, indicating critical areas for intervention. The study introduces a novel comprehensive analysis by integrating attitude formation, collective action, and institutional and rational choice theories to understand WM behaviours. This theoretical integration significantly contributes to the field, providing a heterogeneous understanding of the factors influencing WM practices. Furthermore, the research identifies key gaps in WM infrastructure and public engagement, offering innovative recommendations to address these challenges. This study's significant outputs include identifying specific community behaviours towards waste disposal and evaluating the effectiveness of existing WM policies. These findings provide actionable insights for policymakers and stakeholders to develop targeted interventions that promote sustainable WM practices. The study's contributions and recommendations are crucial for advancing environmental sustainability efforts in similar contexts, aligning with the Sustainable Development Goals.

Innovative Strategies for Upcycling Agricultural Residues and Their Various Pharmaceutical Applications.

This review investigates innovative strategies for upcycling agricultural residues into valuable pharmaceutical compounds. The improper disposal of agricultural residues contributes to significant environmental issues, including increased greenhouse gas emissions and ecosystem degradation. Upcycling offers a sustainable solution, transforming these residues into high-value bioproducts (antioxidants, antitumor agents, antidiabetic compounds, anti-inflammatory agents, and antiviral drugs). Nanotechnology and microbial biotechnology have a crucial role in enhancing bioavailability and targeted delivery of bioactive compounds. Advanced techniques like enzymatic hydrolysis, green solvents, microwave processing, pyrolysis, ultrasonic processing, acid and alkaline hydrolysis, ozonolysis, and organosolv processes are explored for their effectiveness in breaking down agricultural waste and extracting valuable compounds. Despite the promising potential, challenges such as variability in residue composition, scalability, and high costs persist. The review emphasizes the need for future research on cost-effective extraction techniques and robust regulatory frameworks to ensure the safety, efficacy, and quality of bioproducts. The upcycling of agricultural residues represents a viable path towards sustainable waste management and production of pharmaceutical compounds, contributing to environmental conservation and public health improvements. This review provides an analysis of the current literature and identifies knowledge gaps, offering recommendations for future studies to optimize the use of agricultural residues in the drug industry.

A greener method to recover critical metals from spent lithium-ion batteries (LIBs): Synergistic leaching without reducing agents.

Efficient recycling of critical metals from spent lithium-ion batteries is vital for clean energy and sustainable industry growth. Conventional methods often fail to manage large waste volumes, leading to hazardous gas emissions and dangerous materials. This study investigates innovative methods for recovering critical metals from spent LIBs using synergistic leaching. The first step optimized thermal treatment conditions (570 °C for 2 h in air) to remove binder materials while maintaining cathode material crystallinity, confirmed by X-ray diffraction (XRD) analysis. Next, response surface methodology (RSM), I-optimal, was used to examine the synergistic effects of sulfuric acid (SA) and organic acids (Org, citric and acetic acids) and their concentrations (SA: 0.5-2 M and Org: 0.1-2 M) on metal leaching for an eco-friendlier process. Results showed that adding citric acid to SA was more effective, especially at lower concentrations, than using acetic acid. The medium was tested to evaluate the impact of reductant addition. Remarkably, it was discovered that the optimized leaching mixture (1.25 M SA and 0.55 M citric acid) efficiently extracted metals without the need for any reductant like H2O2, highlighting its potential for a simpler and more eco-friendly recycling process. Further optimization identified the ideal solid-to-liquid ratio (62.5 g/L) to minimize acid use. Finally, RSM (D-optimal) was used to investigate the effects of time and temperature on leaching, achieving remarkable recovery rates of 99% ± 0.7 for Li, 98% ± 0.0 for Co, 90% ± 6.6 for Ni, and 92% ± 0.4 for Mn under optimized conditions at 189 min and 95 °C. Chemical cost analysis revealed this method is about 25% more cost-effective than conventional methods.

The P-graph approach in optimal synthesis and planning of waste management towards achieving sustainable development goals: A systematic review.

Effective waste management remains a challenge in global environmental sustainability, underlining the urgent necessity for innovative solutions. This review explored waste management strategies, focusing on the role of P-graph frameworks in achieving sustainable development goals (SDGs). P-graphs offer a systematic approach across domains including, chemical reaction routes, carbon management networks, economic systems and resource planning to waste management synthesis and planning. Through a systematic search and analysis of relevant P-graph approaches, 28 articles meeting the inclusion criteria were selected for review. The study reveals that P-graph approach is a systematic methodology that can streamline decision-making processes, which ultimately lead to more efficient and effective waste management strategies and solutions. This research also highlighted the absence of previous studies on the application of the P-graph approach to various types of waste, underscoring its significance and originality in the field. This study seeks to advance the achievement of SDGs and promote sustainable waste management practices through the integration of the P-graph framework with waste management solutions.

Geopolymer Materials from Fly Ash-A Sustainable Approach to Hazardous Waste Management.

This study explores the utilisation challenges of fly ash from municipal waste incineration, specifically focusing on ash from a dry desulphurisation plant (DDS), which is categorised as hazardous due to its high heavy metal content. The ash's low silicon and calcium contents restrict its standalone utility. Laboratory investigations initially revealed that geopolymers derived solely from fly ash after flue gas treatment (FGT), in combination with coal combustion fly ash, exhibited low compressive strength (below 0.6 MPa). However, the study demonstrated significant improvements by modifying the FGT ash through water leaching. This process enhanced its performance when mixed with high-silica and -aluminium fly ash, resulting in geopolymers achieving compressive strengths of up to 18 MPa. Comparable strength outcomes were observed when the modified ash was blended with commercial cement. Leachability tests conducted for heavy metals (HMs) such as copper, zinc, lead, cadmium, and nickel indicated that their concentrations fell below the regulatory limits for landfill disposal: 2, 4, 0.5, 0.04, and 0.4 mg/kg, respectively. These results underscore the effectiveness of water-washing FGT ash in conjunction with other materials for producing geopolymers, contributing to sustainable waste management practices.

Towards Sustainable Solid Waste Management Systems: Empirical Evidence From Northern Malawi.

Solid waste management system in Mzuzu City is a growing concern due to its inefficiency and the resulting effect of accumulation of solid waste. In light of this environmental challenge, a study was conducted to assess the system's effectiveness. Through a mixed methods approach and random sampling, 400 respondents from 5 different areas of the city of Mzuzu were selected to provide comprehensive and unbiased responses. It was found that both the public and private sectors lack a complete commitment to sustainable waste management, citing reasons such as limited knowledge on recycling benefits, inadequate infrastructure and budgetary constraints. As a solution, the study proposes a government-led campaign to change attitudes towards waste production and promote recycling. Additionally, a Public-Private Partnership (PPP) should be utilised to develop policies and strategies that encourage private sector involvement in eco-friendly waste management. To further enhance recycling practices, support is needed in transitioning to circular economy waste management practices through regular education and training.

Energy from waste biomass: an LCA study on a biofuel cell at early design stage.

Diversifying energy sources and managing waste biomass are two pressing contemporary issues. The new technology proposed in this study aims to address both by converting waste biomass into energy and fertilizer through the use of a biofuel cell (BFC). The purpose of this study is to assess the environmental impacts associated with this innovative technology through a Life Cycle Assessment (LCA). To achieve the goal, the production and use of the cell were modelled, considering both laboratory-scale operations and industrial-scale approximations. The study explored alternative scenarios, such as sensitivity analyses involving different acids and bases, renewable energy sources, and heat recovery. Comparisons with conventional biomass waste treatments (anaerobic digestion and composting) demonstrated that the BFC technology remains competitive. To further improve the BFC's environmental footprint, efforts should focus on reducing energy requirements and enhancing nutrient recovery during scale-up. These insights are crucial for advancing sustainable waste treatment technologies and maximizing the potential of discarded biomass in an environmentally friendly manner.

A quantitative comparison of macro-plastic debris between undisturbed and populous coastal ecosystems of West Bengal, India.

Unmanaged plastic debris from both terrestrial and aquatic sources is causing havoc on Indian coastlines. Tajpur Beach and Haliday Island were selected as two distinct coastal ecosystems in West Bengal for inventorying sighted macro-plastics, aiming to assess their distribution and compare pollution levels. This study employs a comprehensive methodological approach, integrating field-based observations along with lab-based measurements, and information derived from geospatial analysis. Total 34 random points across two study sites were considered for the physical, chemical, and biological characterization of macro-plastics to assess their relative abundance. Areas with higher human footfalls exhibited greater accumulation of plastic debris, with polypropylene, either alone or in combination with polyurethane and polystyrene, identified as highly toxic. Fragmented plastic debris was prevalent at both test sites, yet undisturbed Haliday Island exhibited an abundance of less fragmented materials. Emphasis was also given on implementing appropriate management regimes to achieve plastic-free diverse coastal landscapes.

Green energy innovation initiatives for environmental sustainability: current state and future research directions.

Worldwide, all countries have been facing the crisis of climate change problem. They have been addressing this issue by focusing on implementing green energy innovation initiatives and promoting a sustainable future through environmental sustainability. In this research study, we focus on examining the role of green finance through green energy innovations, which are taking place in several sectors across different regions to promote environmental sustainability. The study has analysed 152 articles on this research domain through a systematic literature review to understand the present state of existing knowledge. The current study examines the Scopus-indexed research articles from the time period 2002 to 2023. Six emerging themes have been examined to understand their development and the potential impact of green initiatives for environmental sustainability. Various institutional theories have been explored to understand their association with the investigated research area. The paper has discussed multiple challenges that need to be addressed for the speedy implementation of green innovations. Finally, future research questions have been proposed based on the findings from the extant literature and the existing research gaps.

Intelligent and sustainable waste classification model based on multi-objective beluga whale optimization and deep learning.

Resource recycling is considered necessary for sustainable development, especially in smart cities where increased urbanization and the variety of waste generated require the development of automated waste management models. The development of smart technology offers a possible alternative to traditional waste management techniques that are proving insufficient to reduce the harmful effects of trash on the environment. This paper proposes an intelligent waste classification model to enhance the classification of waste materials, focusing on the critical aspect of waste classification. The proposed model leverages the InceptionV3 deep learning architecture, augmented by multi-objective beluga whale optimization (MBWO) for hyperparameter optimization. In MBWO, sensitivity and specificity evaluation criteria are integrated linearly as the objective function to find the optimal values of the dropout period, learning rate, and batch size. A benchmark dataset, namely TrashNet is adopted to verify the proposed model's performance. By strategically integrating MBWO, the model achieves a considerable increase in accuracy and efficiency in identifying waste materials, contributing to more effective waste management strategies while encouraging sustainable waste management practices. The proposed intelligent waste classification model outperformed the state-of-the-art models with an accuracy of 97.75%, specificity of 99.55%, F1-score of 97.58%, and sensitivity of 98.88%.

Performance of wood waste biochar and food waste compost in a pilot-scale sustainable drainage system for stormwater treatment.

Sustainable drainage system (SuDS) for stormwater reclamation has the potential to alleviate the water scarcity and environmental pollution issues. Laboratory studies have demonstrated that the capacity of SuDS to treat stormwater can be improved by integrating biochar and compost in the filter media, whereas their performance in scaled-up applications is less reported. This study examines the effectiveness of a pilot-scale SuDS, bioswale followed by bioretention, amended with wood waste biochar (1, 2, and 4 wt.%) and food waste compost (2 and 4 wt.%) to simultaneously remove multiple pollutants including nutrients, heavy metals, and trace organics from the simulated stormwater. Our results confirmed that SuDS modified with both biochar (2 wt.%) and compost (2 wt.%) displayed superior water quality improvement. The system exhibited high removal efficiency (> 70%) for total phosphorus and major metal species including Ni, Pb, Cd, Cr, Cu, and Zn. Total suspended solids concentration was approaching the detection limit in the effluent, thereby confirming its capability to reduce turbidity and particle-associated pollutants from stormwater. Co-application of biochar and compost also moderately immobilized trace organic contaminants such as 2,4-dichlorophenoxyacetic acid, diuron, and atrazine at field-relevant concentrations. Moreover, the soil amendments amplified the activities of enzymes including ß-D-cellobiosidase and urease, suggesting that the improved soil conditions and health of microbial communities could possibly increase phyto and bioremediation of contaminants accumulated in the filter media. Overall, our pilot-scale demonstration confirmed that the co-application of biochar and compost in SuDS can provide a variety of benefits for soil/plant health and water quality.

Machine learning application for predicting key properties of activated carbon produced from lignocellulosic biomass waste with chemical activation.

The successful application of gradient boosting regression (GBR) in machine learning to forecast surface area, pore volume, and yield in biomass-derived activated carbon (AC) production underscores its potential for enhancing manufacturing processes. The GBR model, collecting 17 independent variables for two-step activation (2-SA) and 14 for one-step activation (1-SA), demonstrates effectiveness across three datasets-1-SA, 2-SA, and a combined dataset. Notably, in 1-SA, the GBR model yields R2 values of 0.76, 0.90, and 0.83 for TPV, yield, and SSA respectively, and records R2 of 0.90 and 0.91 for yield in 2-SA and combined datasets. The model highlights the significance of the soaking procedure alongside activation temperature in shaping AC properties with 1-SA or 2-SA, illustrating machine learning's potential in optimizing AC production processes.

Leaching characteristics of nutrients in food waste digestate-derived biochar.

Food waste anaerobic digestion requires proper utilization of solid digestate, and pyrolysis emerges as an effective method to produce nutrient-rich biochar. This study investigated the leaching characteristics and speciation changes of nutrients in food waste digestate (FWD)-derived biochar pyrolyzed at 350 °C (BC350), 450 °C (BC450), and 550 °C (BC550). BC350 featured inorganic nitrogen, while BC450 and BC550 contained elevated organic nitrogen. Nitrogen, potassium, and dissolved organic carbon were released via a quick surface wash-off process. Polyphosphates prevailed in BC350 and leached through a fast diffusion-controlled process. BC450 and BC550 were dominated by Ca/Mg orthophosphates and released via a slow dissolution-controlled process. Leachates from BC450 and BC550 stimulated the shoot length of wheat seeds. After 5 leaching cycles, there were more aromatic dissolved organics, and BC450 and BC550 exhibited higher abundance of C-N and O-P-O. Overall, pyrolysis of FWD at 450 °C and 550 °C shows potential in producing slow-release biochar fertilizers for resource recycling.

Mineral-mediated stability of organic carbon in soil and relevant interaction mechanisms.

Soil, the largest terrestrial carbon reservoir, is central to climate change and relevant feedback to environmental health. Minerals are the essential components that contribute to over 60% of soil carbon storage. However, how the interactions between minerals and organic carbon shape the carbon transformation and stability remains poorly understood. Herein, we critically review the primary interactions between organic carbon and soil minerals and the relevant mechanisms, including sorption, redox reaction, co-precipitation, dissolution, polymerization, and catalytic reaction. These interactions, highly complex with the combination of multiple processes, greatly affect the stability of organic carbon through the following processes: (1) formation or deconstruction of the mineral-organic carbon association; (2) oxidative transformation of the organic carbon with minerals; (3) catalytic polymerization of organic carbon with minerals; and (4) varying association stability of organic carbon according to the mineral transformation. Several pieces of evidence related to the carbon turnover and stability during the interaction with soil minerals in the real eco-environment are then demonstrated. We also highlight the current research gaps and outline research priorities, which may map future directions for a deeper mechanisms-based understanding of the soil carbon storage capacity considering its interactions with minerals.

Waste to energy, indispensable cornerstone for circular economy: A mini-review.

This mini-review aims at proving that waste-to-energy (WtE) is an essential cornerstone for circular economy (CE). Based on literature, the history of thermal waste treatment over the last 150 years is investigated, from open burning to WtE with resource recovery and final sink function. The results show that in the past incineration solved the issues it was designed for but often created new and sometimes even worse problems: The introduction of incineration in the 19th century improved urban sanitation, decreased waste volume and prolonged operational life of landfills. But it also polluted the environment, triggering an unprecedented scientific and engineering effort of all stakeholders. Today, WtE is one of the best investigated and optimized technologies in waste management. It enables the recovery of energy as heat and electric power and facilitates the 'cleaning' of cycles by the destruction of hazardous organic substances. Recent developments in resource recovery from WtE residues allow to recycle metals and, in the case of sewage sludge, even phosphorus by thermal recycling. Combined with carbon capture and storage technology, WtE stands for a quantifiable contribution to greenhouse gas reduction. Today, WtE is indispensable to reach the goals of CE, namely recycling of energy and materials, supplying safe final sinks for persistent organic substances and minimizing the need for sinks for hazardous inorganic substances.

Machine learning prediction and interpretation of the impact of microplastics on soil properties.

The annual microplastic (MP) release into soils is 4-23 times higher than that into oceans, significantly impacting soil quality. However, the mechanisms underlying how MPs impact soil properties remain largely unknown. Soil-MP interactions are complex because of soil heterogeneity and varying MP properties. This lack of understanding was exacerbated by the diverse experimental conditions and soil types used in this study. Predicting changes in soil properties in the presence of MPs is challenging, laborious, and time-consuming. To address these issues, machine learning was applied to fit datasets from peer-reviewed publications to predict and interpret how MPs influence soil properties, including pH, dissolved organic carbon (DOC), total P, NO3--N, NH4+-N, and acid phosphatase enzyme activity (acid P). Among the developed models, the gradient boost regression (GBR) model showed the highest R2 (0.86-0.99) compared to the decision tree and random forest models. The GBR model interpretation showed that MP properties contributed more than 50% to altering the acid P and NO3--N concentrations in soils, whereas they had a negligible impact on total P and 10-20% impact on soil pH, DOC, and NH4+-N. Specifically, the size of MPs was the dominant factor influencing acid P (89.3%), pH (71.6%), and DOC (44.5%) in soils. NO3--N was mainly affected by the MP type (52.0%). The NH4+-N was mainly affected by the MP dose (46.8%). The quantitative insights into the impact of MPs on soil properties of this study could aid in understanding the roles of MPs in soil systems.

Enhanced adsorption of aromatic VOCs on hydrophobic porous biochar produced via microwave rapid pyrolysis.

To customize biochar suitable for efficient adsorption of benzene derivatives, this study presents programmed microwave pyrolysis to produce hydrophobic porous biochar with low-dose ferric chloride. Designated control of the ramping rates in the carbonization stage and the temperatures in the activation stage were conducive to enlarging the specific surface area. Iron species, including amorphous iron minerals, could create small-scale hotspots during microwave pyrolysis to promote microporous structure development. Compared with conventional pyrolysis, programmed microwave pyrolysis could increase the specific surface area from 288.6 m2 g-1 to 455.9 m2 g-1 with a short heating time (15 min vs. 2 h) under 650 °C. Engineered biochar exhibited higher adsorption capacity for benzene and toluene (136.6 and 94.6 mg g-1), and lower adsorption capacity for water vapour (6.2 mg g-1). These findings provide an innovative design of engineered biochar for the adsorption of volatile organic compounds in the environment.

Machine learning for municipal sludge recycling by thermochemical conversion towards sustainability.

The sustainable disposal of high-moisture municipal sludge (MS) has received increasing attention. Thermochemical conversion technologies can be used to recycle MS into liquid/gas bio-fuel and value-added solid products. In this review, we compared energy recovery potential of common thermochemical technologies (i.e., incineration, pyrolysis, hydrothermal conversion) for MS disposal via statistical methods, which indicated that hydrothermal conversion had a great potential in achieving energy recovery from MS. The application of machine learning (ML) in MS recycling was discussed to decipher complex relationships among MS components, process parameters and physicochemical reactions. Comprehensive ML models should be developed considering successive reaction processes of thermochemical conversion in future studies. Furthermore, challenges and prospects were proposed to improve effectiveness of ML for energizing thermochemical conversion of MS regarding data collection and preprocessing, model optimization and interpretability. This review sheds light on mechanism exploration of MS thermochemical recycling by ML, and provide practical guidance for MS recycling.

Towards integrated, and sustainable municipal solid waste management system in Shashemane city administration, Ethiopia.

Solid waste generation is attested to be unavoidable product of human activities. Sustainable management of such waste is a pressing challenge faced in many developing countries today. The study was motivated by the fast growing population and the inefficient waste management system threatening the public health and the image of Shashemene city in Ethiopia. The objectives of the study were: to explore the existing household solid waste management practices, to examine the current governance system of municipal solid waste management, to investigate the contemporary challenges and opportunities of municipal solid waste management, and forward integrated and sustainable municipal solid waste management system for Shashemene city. Data were collected from sampled households, key informants, focus groups, and the city's environment. Data were analyzed by employing quantitative and qualitative methods. 94.8 % of the respondents opined that the solid waste generated in their city is organic in nature (Ash, and sweeps; leftover food, and vegetable peels; paper, and cardboards; green leaves, and grass; and cattle dung). 96.7 % of respondent households opined that they have temporary waste storage in their yards and trash bags were asserted to be widely used (87.6 %) in handling the trash in the courtyard. The waste sorting and recovering practices among the residents is very low and is certainly the major cause for inefficient and unsustainable management system of municipal solid waste in Shashemene city. Generally, a grand mean of 2.23 confirmed the absence of good governance in municipal solid waste management system in Shashemene city. Moreover, the significant proportion of responses ( ≥ 50 %) for each of the nine principles of good governance as either poor or very poor asserted governance failure of the municipal solid waste management system in Shashemene city. The results of the study confirmed that low public awareness on waste management; inadequate collection capacity; poor integration and coordination of stakeholders; environmentally unsound dump site; and illegal dumping by key stakeholders are the major challenges underpinning the unsustainable municipal solid waste management in the city. It is recommended that Shashemene city must adopt integrated sustainable municipal solid waste management system to substantially enhance the waste management service in the city leading to ultimate advancement of public health and environmental quality.

Learning from the past to plan for the future: An historical review of the evolution of waste and resource management 1970-2020 and reflections on priorities 2020-2030 - The perspective of an involved witness.

Improving waste and resource management (WaRM) around the world can halve the weight of plastics entering the oceans, significantly mitigate global heating and contribute directly to 12 of 17 sustainable development goals (SDGs). Achieving such results demands understanding and learning from historical evolution of WaRM. The baseline is 1970, prior to environmental legislation. Early steps in the Global North focused on the 'technical fix' within strictly enforced legal frameworks, first bringing hazardous wastes and municipal solid wastes (MSW) under control, then gradually ramping up environmental standards. Using modern technologies to the Global South often failed due to institutional and financial constraints. From 1990, focus switched to integrating technical and governance aspects: local institutional coherence, financial sustainability, provider inclusivity, user inclusivity, national legislative and policy framework. The Global North rediscovered recycling, using policy measures to promote segregation at source; this relied on new markets in emerging economies, which had largely disappeared by 2020. The Global South is making progress on bringing wastes under control, but around 2.7 billion people lack access to waste collection, while ~40% of collected MSW is open dumped or burned - a continuing global waste emergency. So, much remains to be done to move further towards a circular economy. Three policy priorities are critical for all countries: access to sustainable financing, rethinking sustainable recycling and worldwide extended producer responsibility with teeth. Extending services to unserved communities (SDG11.6.1) requires a people-centred approach, working with communities to provide both quality services and decent livelihoods for collection and recycling workers.