Municipal solid waste management: Dynamics, risk assessment, ecological influence, advancements, constraints and perspectives

Long-term monitoring (2022-2024) of solid waste pollution in inland water ecosystems of Türkiye: Spatial and temporal dynamics

This study provides a comprehensive assessment of solid waste pollution in Türkiye's inland water ecosystems, focusing on the Borçka, Muratlı, and Torul reservoirs, along with Uzungöl Lake, over a three-year period (2022-2024). By employing systematic seasonal sampling, geospatial analysis, and statistical evaluation, the research highlights the spatial and temporal dynamics of solid waste accumulation across these diverse aquatic systems. During the sampling period, a total of 52,666 solid waste items were collected and analyzed from Borçka Dam Lake (29,701 items), Muratlı Dam Lake (6,917 items), Torul Dam Lake (11,635 items), and Uzungöl (4,413 items), revealing significant variations in litter abundance among the lakes, seasons, and years, with Borçka Reservoir having the highest waste density and Uzungöl the lowest. Plastic waste emerged as the dominant category, accounting for over 60% of the total waste in all study sites, followed by metals, glass/ceramics, and paper/cardboard. Statistical analyses, including ANOVA, NMDS, and SIMPER, revealed distinct waste compositions across the lakes and seasons, emphasizing the need for targeted mitigation strategies. This research bridges a significant knowledge gap by focusing on long-term pollution dynamics in Türkiye's inland waters, providing actionable insights for waste management and environmental conservation. Based on the findings of the study, it is recommended to implement effective waste management systems, introduce stricter regulations, and raise public awareness through targeted campaigns.

Aligning priorities: A Comparative analysis of scientific and policy perspectives on municipal solid waste management

Municipal solid waste (MSW) management has become a critical issue today, posing substantial economic, environmental, and social challenges. Identifying and analyzing dominant themes in this field is essential for advancing research and policies towards sustainable MSW management practices. This study aims to explore the key issues related to MSW management that have been addressed by both the scientific community and policymakers through funded projects. By doing so, the study seeks to guide the scientific community as a knowledge producer and the EU as a key funder. Two Latent Dirichlet Allocation (LDA) models were applied to analyze the themes from two corpora: one representing scientific literature and another focusing on EU-funded projects. Additionally, this analysis was complemented by a quantitative estimation of the similarity between the two corpora, providing a measure of alignment between the scientific community and policymakers. The results generally indicate that the two spheres are aligned and highlight the diversity of topics explored by the scientific community. Nevertheless, it is concluded that there are opportunities for further research on specific topics, such as leaching and the extraction of heavy metals. Additionally, the popularity of topics identified in European Union-funded projects has fluctuated considerably over time, focusing primarily on waste management rather than its prevention. In light of these findings, waste prevention emerges as a promising avenue for future EU-funded research initiatives.

Application of the Theory of Planned Behavior to predict waste source separation

Appropriate solid municipal waste management is an important topic in the EU. Abiding by the amended EU Waste Framework Directive and the amended EU Landfill Directive, Greece has set ambitious goals for waste reuse and recycling and for landfill minimization in its recent National Waste Management Plans. These goals however can only be reached through the improvement of the mixed recyclable waste scheme (the "blue bin" scheme for paper/carton, plastic and metal) and the establishment of collection containers for separate waste streams (separately for biodegradable waste, for glass, for paper/carton and for the rest). Active participation of citizens in waste source separation is paramount for this program. As such, the determinants that favor waste source separation intention were measured in approximately 1600 residents in the city of Thessaloniki in Northern Greece, through the application of the Theory of Planned Behavior (TPB). The determinant of Moral Norms (MN) was included in the basic model [that contains the determinants Attitude (ATT), Subjective Norms (SN) and Perceived Behavioral Control (PBC)]. Each determinant was measured through four or five declarations while the Behavioral Intention (BI) contained ten subsections. The model was able to satisfactorily predict the intention of the respondents to perform waste source separation. Specifically, the model successfully predicted respondents' intention to engage in waste source separation, explaining 36 % of the variance, indicating that a moderate amount of variance can be explained by the constructs. There was a significant direct effect of ATT (β = 0.486, p < 0.001), SN (β = 0.091, p < 0.05), and PBC (β = 0.091, p < 0.05) on BI. Additionally, MN showed statistically significant mediating effects; a mediating effect on BI via ATT (β = 0.479; p < 0.01), via SN (β = 0.046; p = 0.015), and via PBC (β = 0.057; p = 0.017) was noted. Implications of these results on waste separation policies include the following: launching comprehensive public education campaigns to reshape positive attitudes, improving infrastructure to strengthen the real or perceived behavioral control of citizens experience, increasing "peer pressure" via community engagement activities, such as recycling workshops, clean-up drives, and competitions. The important role of moral obligations in the community should be underlined and it may be the long-term key solution; educational programs and campaigns should emphasize the moral obligation of waste separation and integrating environmental ethics into school programs can instill these values from a young age.

Environmental Impact of Waste Treatment and Synchronous Hydrogen Production: Based on Life Cycle Assessment Method

Based on the life cycle assessment methodology, this study systematically analyzes the energy utilization of environmental waste through photocatalytic treatment and simultaneous hydrogen production. Using 10,000 tons of organic wastewater as the functional unit, the study evaluates the material consumption, energy utilization, and environmental impact potential of the photocatalytic waste synchronous hydrogen production system (specifically, the synchronous hydrogen production process of 4-NP wastewater with CDs/CdS/CNU). The findings indicate that potential environmental impacts from the photochemical treatment of environmental waste and synchronous hydrogen production primarily manifest in freshwater ecological toxicity, marine ecological toxicity, terrestrial ecological toxicity, and non-carcinogenic toxicity to humans. These ecological impacts stem from the catalyst's adsorption and metal leaching during the photo-degradation and hydrogen production processes of environmental waste. By implementing reasonable modifications and morphological refinements to the catalyst, these effects can be mitigated while achieving enhanced efficiency in environmental waste processing and simultaneous hydrogen production. The research outcomes provide valuable insights for advancing sustainable development in green technology for environmental waste treatment and energy utilization.

Experimental Study on the Temperature-Dependent Static, Dynamic, and Post-Dynamic Mechanical Characteristics of Municipal Solid Waste

Municipal solid waste (MSW) has huge potential to be recycled as construction material, which would have significant benefits for environmental conservation. However, the cornerstone of this undertaking is a solid comprehension of the mechanical response of MSW in real-world engineering locations, taking into account the effects of stress levels and temperature. In this paper, well-mixed MSW samples were sieved and crushed to produce standardized specimens in cylindrical molds. A series of static, dynamic, and post-cyclic shear tests were conducted on the MSW at temperatures ranging from 5 °C to 80 °C with normal stresses of 50 kPa, 100 kPa, and 150 kPa. The experimental findings demonstrate that the static, dynamic, and post-cyclic mechanical response of MSW presents temperature range-dependency; temperature variation between 5 °C and 20 °C affects MSW's mechanical reaction more than variation in temperature between 40 °C and 80 °C under various stress settings; at 5 °C~80 °C, the static peak shear strength of MSW is the highest, being followed by the post-cyclic peak shear strength, while the dynamic peak shear strength is the lowest; the sensitivity of the dynamic shear strength of MSW to temperature variation is the largest, being followed by the post-cyclic peak shear strength, and the static peak shear strength is the lowest.

Scenedesmus sp. as a phycoremediation agent for heavy metal removal from landfill leachate in a comparative study: batch, continuous, and membrane bioreactor (MBR)

Improper disposal of municipal solid waste led to the release of heavy metals into the environment through leachate accumulation, causing a range of health and environmental problems. Phycoremediation, using microalgae to remove heavy metals from contaminated water, was investigated as a promising alternative to traditional remediation methods. This study explored the potential of Scenedesmus sp. as a phycoremediation agent for heavy metal removal from landfill leachate. The study was conducted in batch, continuous, and membrane bioreactor (MBR). In the batch system, Scenedesmus sp. was added to the leachate and incubated for 15 days before the biomass was separated from the suspension. In the continuous system, Scenedesmus sp. was cultured in a flow-through system, and the leachate was continuously fed into the system with flow rates measured at 120, 150, and 180 mL/h for 27 days. The MBR system was similar to the continuous system, but it incorporated a membrane filtration step to remove suspended solids from the treated water. The peristaltic pump was calibrated to operate at five different flow rates: 0.24 L/h, 0.30 L/h, 0.36 L/h, 0.42 L/h, and 0.48 L/h for the MBR system and ran for 24 h. The results showed that Scenedesmus sp. was effective in removing heavy metals such as lead (Pb), cobalt (Co), chromium (Cr), nickel (Ni), and zinc (Zn) from landfill leachate in all three systems. The highest removal efficiency was observed for Ni, with a removal of 0.083 mg/L in the MBR and 0.068 mg/L in batch mode. The lowest removal efficiency was observed for Zn, with a removal of 0.032 mg/L in the MBR, 0.027 mg/L in continuous mode, and 0.022 mg/L in batch mode. The findings depicted that the adsorption capacity varied among the studied metal ions, with the highest capacity observed for Ni (II) and the lowest for Zn (II), reflecting differences in metal speciation, surface charge interactions, and affinity for the adsorbent material. These factors influenced the adsorption process and resulted in varying adsorption capacities for different metal ions. The study also evaluated the biomass growth of Scenedesmus sp. and found that it was significantly influenced by the initial metal concentration in the leachate. The results of this study suggest that Scenedesmus sp. can be used as an effective phycoremediation agent for removing heavy metals from landfill leachate.

Microbial Electrolysis Cells Based on a Bacterial Anode Encapsulated with a Dialysis Bag Including Graphite Particles

One of the main barriers to MEC applicability is the bacterial anode. Usually, the bacterial anode contains non-exoelectrogenic bacteria that act as a physical barrier by settling on the anode surface and displacing the exoelectrogenic microorganisms. Those non-exoelectrogens can also compete with exoelectrogenic microorganisms for nutrients and reduce hydrogen production. In this study, the bacterial anode was encapsulated by a dialysis bag including suspended graphite particles to improve current transfer from the bacteria to the anode material. An anode encapsulated in a dialysis bag without graphite particles, and a bare anode, were used as controls. The MEC with the graphite-dialysis-bag anode was fed with artificial wastewater, leading to a current density, hydrogen production rate, and areal capacitance of 2.73 A·m-2, 134.13 F·m-2, and 7.6 × 10-2 m3·m-3·d-1, respectively. These were highest when compared to the MECs based on the dialysis-bag anode and bare anode (1.73 and 0.33 A·m-2, 82.50 and 13.75 F·m-2, 4.2 × 10-2 and 5.2 × 10-3 m3·m-3·d-1, respectively). The electrochemical impedance spectroscopy of the modified graphite-dialysis-bag anode showed the lowest charge transfer resistance of 35 Ω. The COD removal results on the 25th day were higher when the MEC based on the graphite-dialysis-bag anode was fed with Geobacter medium (53%) than when it was fed with artificial wastewater (40%). The coulombic efficiency of the MEC based on the graphite-dialysis-bag anode was 12% when was fed with Geobacter medium and 15% when was fed with artificial wastewater.

Hydrothermal liquefaction of composite household waste to biocrude: the effect of liquefaction solvents on product yield and quality

The hydrothermal liquefaction (HTL) of composite household waste (CHW) was investigated at different temperatures in the range of 240-360 °C, residence times in the range of 30-90 min, and co-solvent ratios of 2-8 ml/g, by utilising ethanol, glycerol, and produced aqueous phase as liquefaction solvents. Maximum biocrude yield of 46.19% was obtained at 340 °C and 75 min, with aqueous phase recirculation ratio (RR) of 5 ml/g. The chemical solvents such as glycerol and ethanol yielded a biocrude percentage of 45.18% and 42.16% at a ratio of 6 ml/g and 8 ml/g, respectively, for 340 °C and 75 min. The usage of co-solvents as hydrothermal medium increased the biocrude yield by 35.30% and decreased the formation of solid residue and gaseous products by 19.82% and 18.74% respectively. Also, the solid residue and biocrude obtained from co-solvent HTL possessed higher carbon and hydrogen content, thus having a H/C ratio and HHV that is 1.01 and 1.23 times higher than that of water as hydrothermal medium. Among the co-solvents, HTL with aqueous phase recirculation resulted in higher carbon and energy recovery percentages of 9.36% and 9.78% for solid residue and 52.09% and 56.75% for biocrude respectively. Further qualitatively, co-solvent HTL in the presence of obtained aqueous phase yielded 33.43% higher fraction of hydrocarbons than the pure water HTL and 7.70-17.01% higher hydrocarbons when compared with ethanol and glycerol HTL respectively. Nitrogen containing compounds, such as phenols and furfurals, for biocrudes obtained from all HTL processes, were found to be present in the range of 8.30-14.40%.

Prediction of municipal solid waste generation and analysis of dominant variables in rapidly developing cities based on machine learning - a case study of China

Prediction of municipal solid waste (MSW) generation plays an essential role in effective waste management. The main objectives of this study were to develop models for accurate prediction of MSW generation (MSWG) and analyze the influence of dominant variables on MSWG. To elevate the model's prediction accuracy, more than 50 municipal variables were considered original variables, which were selected from 12 categories. According to the screening results, the dominant variables are classified into four categories: urban greening, population size and residential density, regional economic development and resident income and expenditure. Among the seven machine learning methods, back propagation (BP) neural network has the best model evaluation effect. The R2 of the BP neural network model of Jiangsu, Zhejiang and Shandong provinces were 0.969, 0.941 and 0.971 respectively. The prediction accuracy of Shandong province (93.8%) was the best, followed by Jiangsu province (92.3%) and Zhejiang province (72.7%). The correlation between dominant variables and the MSWG was mined, suggesting that regional GDP and the total retail sales of consumer goods were the most important dominant variables affecting MSWG. Moreover, the MSWG might not absolutely associate with the population size and residential density. The method used in this study is a practical tool for policymakers on regional/local waste management and MSWG control.

Nitrogen in landfills: Sources, environmental impacts and novel treatment approaches

Nitrogen (N) accumulation in landfills is a pressing environmental concern due to its diverse sources and significant environmental impacts. However, there is relatively limited attention and research focus on N in landfills as it is overshadowed by other more prominent pollutants. This study comprehensively examines the sources of N in landfills, including food waste contributing to 390 million tons of N annually, industrial discharges, and sewage treatment plant effluents. The environmental impacts of N in landfills are primarily manifested in N2O emissions and leachate with high N concentrations. To address these challenges, this study presents various mitigation and management strategies, including N2O reduction measures and novel NH4+ removal techniques, such as electrochemical technologies, membrane separation processes, algae-based process, and other advanced oxidation processes. However, a more in-depth understanding of the complexities of N cycling in landfills is required, due to the lack of long-term monitoring data and the presence of intricate interactions and feedback mechanisms. To ultimately achieve optimized N management and minimized adverse environmental impacts in landfill settings, future prospects should emphasize advancements in monitoring and modeling technologies, enhanced understanding of microbial ecology, implementation of circular economy principles, application of innovative treatment technologies, and comprehensive landfill design and planning.

Sustainable waste management and waste-to-energy in the context of a circular economy through various waste management technologies

Inappropriate waste management is a considerable ecological risk, leading to detrimental effects on the soil, air, and water quality. It is imperative to address these concerns promptly to minimize the repercussions of solid waste on public health and the ecosystem. It is evident that the level of economic growth directly impacts waste generation. This study intends to use the life cycle assessment (LCA) technique to evaluate the environmental impacts of four alternative municipal solid waste (MSW) management scenarios in Peshawar City, Pakistan. The goal is to discover an option that is both sustainable and minimizes environmental damage. The study examined the system boundaries encompassing the collection and transportation of MSW, along with its processing and final disposal, employing composting, anaerobic digestion (AD), material recovery facilities (MRF), and landfill methods. Comprehensive field studies and an in-depth literature review provided the data regarding Peshawar's existing MSW management system and the proposed scenarios, all of which was inventoried in the OpenLCA 1.10.3 database. Following data collection, the CML-IA technique was employed to analyze the data, measuring the environmental footprint in terms of climate change potential, human toxicity, acidification potential, photochemical oxidation, and eutrophication. A sensitivity analysis was also performed to identify the influence of varying recycling rates on the environmental strain correlated with the proposed scenarios. The analysis results indicated that scenario S2, which combined composting, landfilling, and MRF, exhibited the least environmental impact compared to the other considered scenarios. Furthermore, the sensitivity analysis reflected an inverse correlation between alterations in the recycling rate and the total environmental impact. To counter the environmental problems arising from waste generation, it is essential to incorporate principles of the circular economy into the MSW management approach.

Nexus of food waste and climate change framework: Unravelling the links between impacts, projections, and emissions

This communication explores the intricate relationship between food waste and climate change, considering aspects such as impacts, projections, and emissions. It focuses on the pressing issue of waste generation and its potential consequences if current trends persist, and emphasises the importance of efficient solid waste management in improving environmental quality and fostering economic development. It also highlights the challenges faced by developing countries in waste collection and disposal, drawing comparisons with the waste utilisation methods used by developed nations. The review delves into the link between food waste and climate change, noting the paradoxical situation of food wastage against the backdrop of global hunger and malnutrition. It underscores the scientific evidence connecting food waste to climate change and its implications for food security and climate systems. Additionally, it examines the environmental burden imposed by food waste, including its contribution to greenhouse gas emissions and the depletion of resources such as energy, water, and land. Besides environmental concerns, this communication also highlights the ethical and socioeconomic dimensions of food waste, discussing its influence on Sustainable Development Goals, poverty, and social inequality. The communication concludes by advocating for collective action and the development of successful mitigation strategies, technological solutions, and policy interventions to address food waste and its climate impacts. It emphasises the need for collaboration, awareness, and informed decision-making to ensure a more sustainable and equitable future.

Dynamic impact of demographic features, FDI, and technological innovations on ecological footprint: evidence from European emerging economies

Climate change effect mitigation is a critical priority for top leaders and communities around the globe. Human-induced environmental issues are affecting humankind's standard of living and development potential and the planetary boundaries. Sustainability objectives aim to enhance environmental quality and ensure sustainable development for all by eliminating social inequalities. This study examines the complex relationships between demographic features, foreign direct investment, technological innovation, and ecological footprint, emphasizing the relevance of population aging, population density, and urbanization in this context. The research uses a selection of emerging European economies during 1995-2018. The reasons for countries' selection are related to the increasing rate of population aging in European countries, the attractiveness for foreign direct investment, the economic growth, and the technological advancement potential these emerging countries possess. In order to investigate the long-run relationship between the selected variables, the study tests the cross-section dependence, homogeneity, and cointegration and uses Konya tests to determine panel causality. Based on Konya methodology, differences between countries in the panel are evidenced and discussed accordingly. Our findings confirm the long-run relationship between environment, technological innovation, population aging, and FDI. The results of this research are highly relevant for policymakers in selected countries for identifying the set of correlations and the relevance of various variables in such national economies. Demographic features such as population aging and population density are critical for Europe, and the results show the impact on the ecological footprint.

Determinants of the transition towards circular economy in SMEs: a sustainable supply chain management perspective

Small and medium-sized businesses (SMEs) increasingly know the benefits of improving resource efficiency and closing loops. These benefits include lowering material costs, establishing competitive advantages, and gaining access to new markets. As a consequence of implementing new regulations, manufacturing companies, particularly those in the automobile industry, are compelled to modify and change their business practices related to the circular economy (CE). More stringent the implementation of environmentally responsible policies and strengthening environmental regulations. CE is the most important factor in improving environmental conditions since it reduces waste and boosts output. This facet calls for the attention of fresh academics and policymakers with years of relevant expertise. Recent studies have investigated how green logistics management might improve a company's overall performance in terms of environmental responsibility. However, we believe that the connection between environmentally responsible companies is not a direct one but rather one that is mediated by the practices of circular economies. We investigate the direct and indirect effects of the environmentally responsible impact of proper logistics management on organizations' overall environmental performance via the application of circular economy practices. Our theoretical underpinnings are the resource-based viewpoint and the resource dependence theory. This research also investigates whether or not the traceability of the supply chain has a mitigating influence on the connections. We evaluated the hypotheses using the PLS-SEM method, drawing on the empirical data provided by 245 Chinese factories considered modest or medium size. The results demonstrate that the management of green logistics has a constructive effect on circular economy practices and businesses' sustainability performance. In addition, although it greatly impacts circular economy practice among SMEs, supply chain traceability does not attenuate the connection between eco-friendly supply chain management and environmental impact. Green logistics management in SMEs is linked to improved sustainability performance via the circular economy practice. To further verify the efficacy of the mediation, we also ran the sober test. Our results strengthen knowledge of circular economy, environmentally friendly logistics management practices, and sustainability performance while advancing natural resource-based planning and the resource dependence theory, which are the two approaches. Given the scarcity of information research analyzing the interplay between these factors, our results are very significant.

New multi-source waste co-incineration and clustering park operating model for small- and medium-sized city: A case study in China

With improvements in urban waste management to promote sustainable development, an increasing number of waste types need to be sorted and treated separately. Due to the relatively low amount of waste generated in small- and medium-sized cities, separate treatment facilities for each waste type lack scale, waste is treated at a high cost and low efficiency. Therefore, industrial symbiosis principles are suggested to be used to guide collaborative waste treatment system of multi-source solid wastes, and co-incineration is the most commonly used technology. Most existing studies have focused on co-incineration of one certain waste type (such as sludge or medical waste) with municipal solid waste (MSW), but the systematic design and the comprehensive benefits on a whole city and park level have not been widely studied. Taking the actual operation of a multi-source waste co-incineration park in south-central China as an example, this study conducted a detailed analysis of the waste-energy-water metabolism process of MSW, sludge, food waste, and medical waste co-incineration. The environmental and economic benefits were evaluated and compared with the single decentralized waste treatment mode. The results showed that the multi-source waste co-incineration and clustering park operating model was comprehensively superior to the single treatment mode, greenhouse gases and human toxicity indicators were decreased by 11.87% and 295.74%, respectively, and the internal rate of return of the project was increased by 29.35%. This mainly benefits from the synergy of technical system and the economies of scale. Finally, this research proposed policy suggestions from systematic planning and design, technical route selection, and an innovative management mode in view of the potential challenges.

Reduction of cost and emissions by using recycling and waste management system

In order to evaluate the level of sustainability of an integrated waste management system (IWMS), it is necessary to analyze the impact criteria. Therefore, the purpose of this study is to provide a model for IWMS optimization with the two goals of minimizing the cost and the emission of greenhouse gases of the entire system. Environmental and health problems caused by the lack of proper waste management include the increase in disease, increase in stray animals, pollution of air, water, land, etc. Therefore, it is very important to identify the indicators and improve the efficiency of the waste management system. In the present research, with descriptive-analytical approach, it has been tried to clarify and evaluate the effective indicators in two dimensions of production-segregation and collection-transportation, and find ways to improve the efficiency of the system. In this article, five waste management systems including, incineration, landfill without gas extraction system, plasma incineration, recycling and aerobic decomposition are introduced and their performance in energy production and emission reduction are compared. The results of the evaluation of the basic waste management system (b) show that the amount of pollution is equivalent to 850 kg CO2 per ton of waste. While the amount of emission in the fifth comprehensive management system is reduced to 450 kg CO2 per ton of waste. According to the results obtained in this study, in all the management systems presented, the process of burying waste in sanitary landfills has the greatest effect in increasing pollution. This means that the pollution caused by burying the waste in the sanitary landfill will be reduced with the construction of the gas extraction system and the plasma method and use in electricity production. Despite the increase in initial costs, using the right technology and using the right waste system based on the type of waste and waste recycling has an effect on the efficiency of the system.

Circular economy strategies in supply chains, enhancing resource efficiency and sustainable development goals

Eco-industrial parks are the real-world implementation of green supply chain management. There is a growing need to include the circular economy concept into supply chain management as a means of striking a better economic, social, and environmental balance, as the importance of the external sustainability of the supply chain is challenging. Using 357 questionnaires filled out by enterprises in China's eco-industrial parks, we examine the connections and causal relationships between resource efficiency, environmental impact, green supply chain management, and circular economy. To learn how a green supply chain's circular economy affects resource efficiency and environmental performance in the China region, this study makes use of the instrumental variable approach (structure equation model (SEM)). The results of this study indicate that environmentally responsible supply chain management and circular economy have beneficial effects on environmental performance and resource efficiency. The management of the GSC has a negative and small impact on economic performance, although each of the components is a substantial contributor to better performance in the environment. Conclusions from this study will assist those responsible for making decisions within supply chains in developing a plan that is useful for increasing a company's performance along economic and environmental dimensions. This study not only broadens our understanding of the factors that influence green supply chain management but also offers theoretical direction for the implementation of successful green production practices by businesses located in eco-industrial parks.

Internet of Things enables smart solid waste bin management system for a sustainable environment

Solid waste management (SWM) is a pressing concern and significant research topic that requires attention from citizens and government stakeholders. Most of the responsibility of waste management is on the municipal sector for its collection, reallocation, and reuse of other resources. The daily solid waste production is more than 54,850 tonnes in urban areas and is difficult to manage due to limited resources and different administrative and service issues. New technologies are playing their role in this area but how to integrate the technologies is still a question, especially for developing countries. This paper is divided into two main phases including a detailed investigation and a technological solution. In the first phase, the data is collected by using the qualitative method to investigate and identify the issues related to waste management. After a detailed investigation and results, the gap is identified by using statistical analysis and proposed a technological solution in the second phase. The technology-based solution is used to control and manage waste with a low-cost, fast, and manageable solution. The new sensor-based technologies, cellular networks, and social media are utilized to monitor the trash in the areas. The trash management department receives notification via cellular services to locate the dustbin when the dustbin reaches a maximum level so the department may send a waste collector vehicle to the relevant spot to collect waste. The smart and fast solution will connect all stakeholders in the community and reduce the cost and time and make the collection process faster. The experiment results indicated the issues and effectiveness of the proposed solution.

Does circular economy affect environmental performance? The mediating role of sustainable supply chain management: the case study in China

Governments and professionals have recently tried to improve public environmental knowledge and laws in order to meet growing environmental concerns. As a result, most nations see corporate environmental initiatives like the circular economy and the green supply chain as important (GSCM) as the best ways to address environmental problems. As a result, this study tries to show how important GSCM and the circular economy are regarding the economy of China's relationship to environmental sustainability. This study uses the partial least square structural equation model (PLS-SEM) on data to obtain trustworthy results from 387 Chinese manufacturing companies. A favorable and statistically significant correlation between GSCM, environmental performance, and the circular economy was revealed using PLS-SEM analysis. To raise environmental standards, eco-friendly methods like buying and designing green items are widely regarded today. Imagine if manufacturing companies adopt green supply chain management, which would improve their economic performance and increase operational effectiveness. The secret to a successful corporation is having successful operations.

Carbon dots/TiO2 enhanced visible light-assisted photocatalytic of leachate: Simultaneous effects and Mechanism insights

The persistence and potential fouling risks associated with humic substances and bacteria present in leachate have gained increasing attention. Therefore, developing efficient and environmentally compatible technologies for their removal is essential. This study presented the hydrothermal synthesis of a photocatalyst by coupling carbon dots (CDs) and bulk TiO2 (P25). The incorporation of CDs increased the photocatalytic performance by enhancing visible light absorption and facilitating the separation of electrons/holes. Compared to P25, the CDs/P25 exhibited optimal photocatalytic activity for humic acid (HA), fulvic acid (FA), and leachate, with 1.64, 1.02, and 1.12 times higher activity, respectively. Remarkedly, the CDs/P25 accelerated the conversion of large HA molecules into small molecules at a faster rate and higher amount than the bulk P25, due to the increase of hydroxyl radicals, monoclinic oxygen radicals, and superoxide radicals. Additionally, the CDs/P25 demonstrated better bacterial-deactivation ability than the P25, with dead bacteria percentages of 83.3% and 34.6%, respectively. This study provides a promising strategy for efficiently applying CDs/P25 photocatalysis to leachate treatment.

The concentration-dependent physiological damage, oxidative stress, and DNA lesions in Caenorhabditis elegans by subacute exposure to landfill leachate

The leakage of landfill leachate (LL) into environmental media would be happened even in the sanitary/controlled landfill, due to the deterioration of geomembrane and the blockage of drainage system after long-term operation. Considering the complex composition and high concentration of pollutants in LL, its toxicity assessment should be conducted as a whole liquid contaminant. Therefore, the impacts of LL on Caenorhabditis elegans (C. elegans) were investigated under the condition of different exposure time and exposure volume fraction (EVF). The stimulating effects on locomotion behavior and growth of C. elegans were observed after acute (24 h) exposure to LL, which were increased firstly and then decreased with the increase of EVF. Meanwhile, the intestinal barrier was not affected by LL, and levels of reactive oxygen species (ROS) and cell apoptosis significantly decreased. However, stimulation and inhibition effects on locomotion behavior and growth of C. elegans were observed when subacute (72 h) exposure to 0.25%-0.5% and 1%-4% of LL, respectively. The intestinal injury index and levels of ROS and cell apoptosis significantly increased when EVF were 2% and 4%. Although the acute exposure of LL had resulted in obviously biological adaptability and antioxidant defense in C. elegans, the protective mechanisms failed to be induced as the exposure time increased (subacute exposure). The toxic effects were confirmed by the down-regulation of genes associated with antioxidant defense and neurobehavior, accompanied by the up-regulation of intestinal injury and cell apoptosis related genes. Moreover, the disturbance of metabolic pathways that associated with locomotion behaviors, growth, and antioxidant defense provided good supplementary evidence for the confirmation of oxidative stress in C. elegans. The research results verified the potential of C. elegans as model organism to determine the complex toxic effects of LL.

A Recent Digitalization in Recycling Industry Attaining Ecological Sustainability: A Comprehensive Outlook and Future Trend

The management of waste through dual way of recycling (i-e offline and online) is assumed to have a key role in attaining ecological sustainability and enabling circular practices. The research on online recycling is gaining evolution in recent age. Prior literature on the current research theme has failed to provide a comprehensive outlook and future trend. Therefore, the current research intends to elaborate the current research scenario linked with online recycling by critically scrutinizing the prior research over the last 41 years. A comprehensive analysis was conducted using the Scopus database, retrieving a total of 866 articles. These articles were selected to provide a conceptual overview and understanding of the fundamental research conducted in the field. By employing bibliometric analysis this research provides comprehensive detail about evolution, mapping of publications and prominent trends from the year 1981 to 2022 to understand the practices and future trends of online recycling research. The outcomes elucidated that there is exponential increase in research publications relating to online recycling over the last five years. The most influential producer of online recycling research are China, United Kingdom and United States. Chinese Universities has the highest number of publications among all the countries across globe. Moreover, the current research trend is focused on technology based circular economy, industrial ecology, bio-based waste management, dual channel recycling, municipal waste, waste from electrical and electronic equipment (WEEE), environmental impact and lifecycle assessment. Hence, the prominent research perspective and highlighted features could offer recommendation for upcoming studies to contribute in literature and help practitioners, policymakers and professionals move towards circular practices.

An unexpected contribution of higher education towards the innovations: the moderate role of green technology

Understanding how environmental restrictions affect the relationship between economic stability and unbalanced technical innovation is crucial for optimizing environmental and financial policy frameworks in developing nations to achieve sustainable development goals (SDGs). Understanding the driving effect of green funding on green development is vital for promoting economic transformation and achieving long-term green growth. Green growth is one of the most exciting new strategies for sustained economic expansion. Despite environmental technology's significance, further study is required to ascertain whether and how environmental technologies affect green development. Therefore, the purpose of this study is to examine how environmental technology may promote green growth in the G7 by reducing reliance on renewable and non-renewable energy sources. Investing in higher education is the most powerful thing a society can do intellectually if it is serious about attaining sustainability by applying skills, providing consulting, delivering training, and disseminating knowledge. Thus, the paper analyzes how the G7 countries' pursuit of green economic development is affected by economic policy uncertainty, investments in renewable energy, human capital, and health expenditure. The G7 economies' panel data from 2005 to 2021 was used to verify the assertions using the GMM estimate. Additional generalized method of moment (GMM) tests, including a one-step test and a two-step test with a robust check, are used to estimate the variables in this study. The research shows that economic policy uncertainty and health expenditure have negative effects on green economic growth, whereas investments in renewable energy, green finance, human capital, and an ageing population have favorable effects. The research findings direct the formulation of policy implications that would maintain the role of green financing as a growth engine in the Chinese economy.

Assessing the supply chain management of waste-to-energy on green circular economy in China: an empirical study

One of the industries that makes a significant contribution to the overall amount of greenhouse gas emissions around the globe is agriculture. In this regard, the use of bioenergy in the agricultural and food processing industries might benefit from the implementation of circular economy techniques. Despite the fact that just roughly 9% of the global economy is circular, there have been worldwide efforts to improve that reality. The linear economy, commonly known as the "take-make-use-dispose" model, is in sharp contrast to the circular economy, also known as "grow-make-use-restore," which seeks to influence the flow of materials and energy in order to maximize the benefits to the environment and minimize any associated costs. Garbage-to-energy, also known as WTE, is the focus of both academics and businesses as a direct result of the increasingly diminishing number of energy supplies and the ever-increasing amount of garbage. This project intends to turn trash into profit, lessen the impact waste has on the environment, and generate energy from biowaste by conceptualizing a focus on the supply chain characteristics of waste-to-energy processing. The adoption of a waste-to-energy (WTE) supply chain as a district energy system should be a viable solution toward a circular industrial economy that can solve energy consumption, waste management, and greenhouse gas emission concerns all at once. In the framework of a "circular economy," this study investigates how the management of waste-to-energy supply chains impacts the performance of businesses. The present investigation makes use of life cycle assessments, technical innovation, waste-to-energy conversion, and capacities related to circular economies. The study makes use of data obtained from an online survey that was administered between March 2021 and November 2021 to employees of 285 representative samples drawn from 457 European enterprises and firms that have accepted the concepts of the circular economy. The data is examined using a technique known as partial least squares structural equation modeling (PLS-SEM for short). The findings indicate that waste-to-energy serves as a mediator between the life cycle assessment and the capabilities of the circular economy and that sustainable supply chain management, sustainable supply chain design, technological progress, and waste-to-energy all have positive effects on these metrics.

Inoculation with thermophiles enhanced the food waste bio-drying and complicated interdomain ecological networks between bacterial and fungal communities

Bio-drying is a practical approach for treating food waste (FW). However, microbial ecological processes during treatment are essential for improving the dry efficiency, and have not been stressed enough. This study analyzed the microbial community succession and two critical periods of interdomain ecological networks (IDENs) during FW bio-drying inoculated with thermophiles (TB), to determine how TB affects FW bio-drying efficiency. The results showed that TB could rapidly colonize in the FW bio-drying, with the highest relative abundance of 5.13%. Inoculating TB increased the maximum temperature, temperature integrated index and moisture removal rate of FW bio-drying (55.7 °C, 219.5 °C, and 86.11% vs. 52.1 °C, 159.1 °C, and 56.02%), thereby accelerating the FW bio-drying efficiency by altering the succession of microbial communities. The structural equation model and IDEN analysis demonstrated that TB inoculation complicated the IDENs between bacterial and fungal communities by significantly and positively affecting bacterial communities (b = 0.39, p < 0.001) and fungal communities (b = 0.32, p < 0.01), thereby enhancing interdomain interactions between bacteria and fungi. Additionally, inoculation TB significantly increased the relative abundance of keystone taxa, including Clostridium sensu stricto, Ochrobactrum, Phenylobacterium, Microvirga and Candida. In conclusion, the inoculation of TB could effectively improve FW bio-drying, which is a promising technology for rapidly reducing FW with high moisture content and recovering resources from it.

An integration of oil price volatility, green energy consumption, and economic performance: assessing the mediating role of trade

The economic development of globalized economies is facing severe challenges in the context of a new era. Therefore, the purpose of the study is to assess how crucial factors like oil price fluctuations, renewable energy use, economic growth, the exchange rate, exports, imports, and trade affect the economic performance in the top 25 oil-importing countries using panel data from 2005 to 2021 collected annually. The present investigation employs a method for calculating the stability of associations between variables called AMG estimation. The robustness and reliability of CCEMG and DCCEMG estimates are tested in the present study. Consumption, exports, and trade in renewable energy all had a favorable effect on economic growth. The fluctuation of oil prices, the state of the economy, the currency exchange rate, and imports make things worse. In addition, the findings of the study indicate that the moderate effect of trade with fluctuating oil prices, rising finance, and economic expansion is aided by the current exchange rate. In addition to helping create an appropriate path forward for economic growth, the computed coefficients have policy implications for both the chosen developing economy and the other markets.

Ecological risk identification and assessment of land remediation project based on GIS technology

A land remediation project involves the removal of potentially toxic chemicals from a polluted site. Lands abandoned by industry are often contaminated with heavy metals like mercury, lead, chemicals, arsenic, and other toxins like dichlorodiphenyltrichloroethane biphenyls from electronic devices, and volatile organic chemicals (VOCs) from lubricants and chemicals. Risk assessment in environmental settings requires modernized systematic methodologies due to the complexity of today's environmental problems. When people eat, drink, or work in polluted environments, they put their health at risk and may even get cancer. Integrating geospatial information systems (GIS) with pollutant dispersion models makes environmental risk assessment and early warning possible. This research thus presents a GIS-based ecological risk identification and assessment model (GIS-ERIAM) for assessing risk for efficient land rehabilitation. Environmental cleanup sites' catalog information is the source of these details. With satellite imagery, GIS makes it simple to keep an eye on the environment and track the abundance of different types of plants and animals The ecological risk assessment (ERA) model can support recognition and prioritize risk management. By integrating direct and indirect environment interactions, the risk conditions of the whole ecology and its elements have been quantified and demonstrated in the study. The numerical outcomes illustrate that the recommended GIS-ERIAM model improves the performance by 98.9%, risk level prediction by 97.3%, risk classification by 96.4%, and detection of soil degradation ratio of 95.6% compared to other existing methods.

Modeling and Performance Analysis of Municipal Solid Waste Treatment in Plasma Torch Reactor

Thermal plasma has emerged as a technology with tremendous promise for municipal wastes that should be disposed of sustainably. A numerical simulation of a symmetric turbulent plasma jet from a thermal air plasma torch was developed using COMSOL Multiphysics®5.4 engineering simulation software. The velocities, temperature, arc root motion, and joule heating of the plasma jet were examined under the impact of the gas mass flow rate and current. Moreover, the electrical power required for the municipal solid waste (MSW) processing was estimated. The enthalpy and the effectiveness of the plasma torch were analyzed and discussed. Subsequently an investigation was conducted into the gasification characteristics of MSW using air and steam gases. The torch’s power and efficiency could be enhanced with a higher mass flow rate and temperature. Three operating modes were identified from the current–arc flow combination. Among the plasma gas considered, the air gas plasma torch guarantees an acceptable thermal efficiency and a low anode erosion rate. Plasma gasification produces cleaner syngas with higher efficiency (84%) than the conventional process due to the elevated temperature used during the process that breaks down all the char, dioxins, and tars.

Pilot-scale treatment of municipal garbage mechanical dewatering wastewater by an integrated system involving partial nitrification and denitrification

The municipal solid waste (MSW) with high water content can be pre-treated by the mechanical dewatering technology to significantly decrease the leachate generation in sequential landfill treatment or to improve the efficiency for solid waste incineration, which has attracted great concerns recently. However, the generated mechanical dewatering wastewater (MDW) containing high organics and nitrogenous content has been one of the big challenges for the sustainable treatment of MSW. In this study, a pilot-scale integrated system composed of physiochemical pretreatment, anaerobic sequencing batch reactor (ASBR), partial nitrification SBR (PN-SBR), denitrification SBR (DN-SBR), and UV/O₃ advanced oxidation process, with a capacity of 1.0 m³/d to treat MDW containing over 34000 mg-chemical oxygen demand (COD)/L organics pollutant and 850 mg/L NH₄⁺-N, was successfully developed. By explorations on the start-up of this integrated system and the process conditions optimization, after a long-term system operation, the findings demonstrated that this integrated system could reach the removal efficiency in the COD, NH₄⁺-N and total nitrogen (TN) in the MDW of 99.7%, 98.2% and 96.9%, respectively. Partial nitrification and denitrification were successfully obtained for the TN removal with the nitrite accumulation rate of over 80%. The treatment condition parameters were optimized to be 800 mg/L polyaluminum chloride (PAC) and 2 mg/L polyacrylamide (PAM) under a pH of 9 for pretreatment, 36 h hydraulic retention time (HRT) for ASBR, 24 h for PN-SBR, and 2 h for UV/O₃ unit. The organic sources in the MDW were also found to be feasible for the DN-SBR. Consequently, the resulting final effluent was stably in compliance with the discharge standard with high stability and reliability.

Thermal co-treatment of aluminum dross and municipal solid waste incineration fly ash: Mineral transformation, crusting prevention, detoxification, and low-carbon cementitious material preparation

Harmless disposal and resource utilization of hazardous industrial wastes has become an important issue with the green development of human society. However, resource utilization of hazardous solid wastes, such as the production of cementitious materials, is usually accompanied by a pretreatment process to remove adverse impurities that contaminate the final product. In this study, aluminum dross (AD) was thermally co-treated with another hazardous waste, municipal solid incineration fly ash (MSWI-FA), to synergistically solidify F and Na, control leaching of heavy metals, and remove chloride impurities. Significant crusting was observed when AD was thermally treated by itself, but not when AD and MSWI-FA were thermally co-treated. In the process of co-thermal treatment, the remaining Cl, Na, and K contents were reduced to as low as 0.3%, 1.8%, and 0.6%, respectively. CaO and SiO₂ in MSWI-FA reacted with Na₃AlF₆ and Al₂O₃ in AD, and formed CaF₂ and Na₆(AlSiO₄)₆, which contributed to the prevention of crusting and limited the leaching concentrations of F and Na to below detection thresholds and 270.6 mg/L, respectively. In addition, heavy metals were well solidified, and dioxins were fully decomposed during thermal treatment. Finally, a sulfoaluminate cementitious material (SACM) with high early- and later-age strengths was successfully created via synergetic complementarity using thermally co-treated AD and MSWI-FA together with other solid wastes. Collectively, this study outlines a promising method for the efficient and sustainable utilization of AD and MSWI-FA.

World development and generation of waste

Nowadays, it is almost impossible to argue about global development without immediately stopping to think about waste; it is claimed that waste materials are correlated with the growth of the population as a consequence of consumption habits. The applied multivariable statistical analysis, both quantitative and qualitative of the BIG DATA of the OECD in the period of 1960-2050 of the World Bank from the decades of 1990-2020, and SCOPUS (1996-2020) using applied multivariate statistics. The results reveal that consumption habits are strongly influenced by access to public services more than by purchasing power, in addition, it was determined that the rate of subscriptions to cellular service is a catalyst for population indicators and ordinary waste middle tight (RO) of 0.96 m³ for person daily, study shows the trace of evolution due to the most significant advance in communication technologies, important findings for the construction of solutions within the concepts of circular economy, sustainable development, social market economy, and social responsibility.

Retrofitting a full-scale multistage landfill leachate treatment plant by introducing coagulation/flocculation/sedimentation and ultrafiltration process steps

Considering that landfilling still remains among the most commonly used methods for the confrontation of solid wastes, effective methods should be applied to treat the leachate generated, due to its recalcitrant nature. In this work, a full-scale system consisting of two SBRs operating in parallel (350 m³ each) and two activated carbon (AC) columns operating in series (3 m³ each) was retrofitted by introducing a coagulation/flocculation/sedimentation (C/F/S) unit of 7.8 m³ and an ultrafiltration (UF) membrane of 100 m² to effectively treat landfill leachate. The raw leachate was characterized by high COD and NH₄⁺-N concentration, i.e., 3095 ± 706 mg/L and 1054 ± 141 mg/L respectively, a BOD/COD ratio of 0.22, and high concentrations of certain heavy metals. Leachate processing in this retrofitted multistage treatment system resulted in total COD removal efficiency of 89.84%, with biological treatment, C/F, UF, and AC contributing 46.31%, 4.68%, 15.98%, and 22.87% to the overall organic content removal. The retrofitted scheme achieved an overall NH₄⁺-N and TKN removal of 92.03% and 91.75% respectively, attributed mostly to the activity of an effective nitrifying community. Color number (CN) was reduced by 26.96%, 10.29%, 15.94%, and 5.39% after the activated sludge, the C/F, the UF, and the AC adsorption process respectively, corresponding to a 58.91% overall decrease. Regarding heavy metal removal, all elements examined, apart from Ni, i.e., effluent As, Cd, Co, Cr, Cu, Hg, Mg, Mn, and Pb, were below the legislative limits set by the national authorities for restricted or unrestricted irrigation. Lastly, total operating expenses (OPEX) were estimated as equal to 72,687 €/year or 6.64 €/m³.

How publications and patents are contributing to the development of municipal solid waste management: Viewing the UN Sustainable Development Goals as ground zero

Academia and industry have strengthened each other under the guidelines of regulatory institutions to contribute theoretical knowledge and practical solutions for society, which can be presented in a combination of publishing research and filing patents. In the case of municipal solid waste management (MSWM), a great transformation from a linear to a circular view has been in process. In this study, we investigated the role of the United Nations Sustainable Development Goals (SDGs) in MSWM-related development and transformation. The authors examined the contributions of academic and industrial spheres to MSWM in the past 70 years by examining Web of Science's Core Collection and Derwent Innovations Index. The results showed that SDGs not only accelerated the research on MSWM but also pulled MSWM-related knowledge and innovation to new fronts that focus on sustainable and circular methods. Based on the current findings, we derived implications for academia, industry, and policymakers.

A review on biological methodologies in municipal solid waste management and landfilling: Resource and energy recovery

Rapid industrialization and urbanization growth combined with increased population has aggravated the issue of municipal solid waste generation. MSW has been accounted for contributing tremendously to the improvement of sustainable sources and safe environment. Biological processing of MSW followed by biogas and biomethane generation is one of the innumerable sustainable energy source choices. In the treatment of MSW, biological treatment has some attractive benefits such as reduced volume in the waste material, adjustment of the waste, economic aspects, obliteration of microorganisms in the waste material, and creation of biogas for energy use. In the anaerobic process the utilizable product is energy recovery. The current review discusses about the system for approaching conversion of MSW to energy and waste derived circular bioeconomy to address the zero waste society and sustainable development goals. Biological treatment process adopted with aerobic and anaerobic processes. In the aerobic process the utilizable product is compost. These techniques are used to convert MSW into a reasonable hotspot for resource and energy recovery that produces biogas, biofuel and bioelectricity and different results in without risk and harmless to the ecosystem. This review examines the suitability of biological treatment technologies for energy production, giving modern data about it. It likewise covers difficulties and points of view in this field of exploration.

Bioconversion of biowaste into renewable energy and resources: A sustainable strategy

Due to its high amount of organic and biodegradable components that can be recycled, biowaste is not only a major cause of environmental contamination, but also a vast store of useful materials. The transformation of biowaste into energy and resources via biorefinery is an unavoidable trend, which could aid in reducing carbon emissions and alleviating the energy crisis in light of dwindling energy supplies and mounting environmental difficulties related with solid waste. In addition, the current pandemic and the difficult worldwide situation, with their effects on the economic, social, and environmental aspects of human life, have offered an opportunity to promote the transition to greener energy and sources. In this context, the current advancements and possible trends of utilizing widely available biowaste to produce key biofuels (such as biogas and biodiesel) and resources (such as organic acid, biodegradable plastic, protein product, biopesticide, bioflocculant, and compost) are studied in this review. To achieve the goal of circular bioeconomy, it is necessary to turn biowaste into high-value energy and resources utilizing biological processes. In addition, the usage of recycling technologies and the incorporation of bioconversion to enhance process performance are analyzed critically. Lastly, this work seeks to reduce a number of enduring obstacles to the recycling of biowaste for future use in the circular economy. Although it could alleviate the global energy issue, additional study, market analysis, and finance are necessary to commercialize alternative products and promote their future use. Utilization of biowaste should incorporate a comprehensive approach and a methodical style of thinking, which can facilitate product enhancement and decision optimization through multidisciplinary integration and data-driven techniques.

Exploring bacterial communities through metagenomics during bioremediation of polycyclic aromatic hydrocarbons from contaminated sediments

The goal of this study was to evaluate the degradation effectiveness of PAHs degrading bacteria at the mesocosm level, including Stenotrophomonas maltophilia (SC), mixed culture (MC), and enriched native microflora (EC) at the mesocosm level. Maximum degradation was found in the mesocosm MC (26.67 %), followed by SC (25.08 %) and EC (18.25 %) after 60 days. Thus, mixed culture and Stenotrophomonas maltophilia could be a game changer in the PAHs bioremediation at the chronically contaminated sites. MiSeq sequencing has revealed dominancy of γ-Proteobacteria, α-Proteobacteria, β-Proteobacteria at class level and Sphingomonadales, oceanospirillales, Rhodothermales at Order level. Families Alcanivoracaceae, Alteromonadaceae, Nocardiaceae, Rhodospirillaceae and genus Stenotrophomonas, Alcanivorax, Methylophaga, Fluviicola and Rhodoplanes were considerably increased which play key role in the PAHs degradation. Dominant bacterial communities have revealed resilience community to enable potential PAHs degradation process in all the mesocosms. To the best our knowledge this is the first ever attempt in PAHs biodegradation study conducted at the mesocosm level mimicking natural environmental conditions. Consequently, this study could be a benchmark against which future progress studies for the policy makers and stakeholders to design appropriate bioremediation study for the historically PAHs polluted contaminate sites.

Prospective review on bioelectrochemical systems for wastewater treatment: Achievements, hindrances and role in sustainable environment

Bioelectrochemical systems (BESs) are a relatively new arena for producing bioelectricity, desalinating sea water, and treating industrial effluents by removing organic matter. Microbial electrochemical technologies (METs) are promising for obtaining value-added products during simultaneous remediation of pollutants from wastewater. The search for more affordable desalination technology has led to the development of microbial desalination cells (MDCs). MDC combines the operation of microbial fuel cells (MFC) with electrodialysis for water desalination and energy generation. It has received notable interest of researchers in desalination and wastewater treatment because of low energy requirement and eco-friendly nature. Firstly, this article provides a brief overview of MDC technology. Secondly, factors affecting functioning of MDC and its applications have been accentuated. Additionally, challenges and future outlook on the development of this technology have been delineated. State-of-the-art information provided in this review would expand the scope of interdisciplinary and translational research.

Impact of divalent cations on lysozyme-induced solubilisation of waste-activated sludge: Perspectives of extracellular polymeric substances and surface electronegativity

Lysozyme hydrolysis can accelerate waste-activated sludge (WAS) solubilisation, which can significantly shorten the process and promote the efficiency of anaerobic digestion. This study investigated the impact of divalent cations on lysozyme-induced solubilisation of WAS. The performance of lysozyme pretreatment was dramatically inhibited by Mg²⁺ and Ca²⁺. Compared to the control group, the amount of net SCOD, protein, and polysaccharides released to the supernatant were reduced by 36.6%, 44.7%, and 35.8%, respectively, in the presence of divalent cations. The extracellular polymeric substance (EPS) matrix became tightly bound, resulting in fewer proteins and polysaccharides being extracted from loosely-bound EPS (LB-EPS) with divalent cations, which was detrimental to the solubilisation of WAS. Divalent cations decreased the surface electronegativity of sludge particles and prolonged the adsorption of lysozymes by sludge flocs. More than 16.6% of total lysozymes remained in the liquid phase of WAS after 240 min Mg²⁺ and Ca²⁺ strengthened the binding among proteins and polysaccharides and promoted the intermolecular cross-linking of polysaccharides. The EPS matrix formed a dense spatial reticular structure that blocked the transfer of lysozymes from the EPS matrix to the pellet. As a result, the lysozymes accumulated in LB-EPS rather than hydrolysing the microorganism's cell wall. This study provides a new perspective on the restriction of WAS pretreatment with lysozymes and optimises the method of lysozyme-induced solubilisation of WAS.

A critical review on microbes-based treatment strategies for mitigation of toxic pollutants

Contamination of the environment through toxic pollutants poses a key risk to the environment due to irreversible environmental damage(s). Industrialization and urbanization produced harmful elements such as petrochemicals, agrochemicals, pharmaceuticals, nanomaterials, and herbicides that are intentionally or unintentionally released into the water system, threatening biodiversity, the health of animals, and humans. Heavy metals (HMs) in water, for example, can exist in a variety of forms that are inclined by climate features like the presence of various types of organic matter, pH, water system hardness, transformation, and bioavailability. Biological treatment is an important tool for removing toxic contaminants from the ecosystem, and it has piqued the concern of investigators over the centuries. In situ bioremediation such as biosparging, bioventing, biostimulation, bioaugmentation, and phytoremediation and ex-situ bioremediation includes composting, land farming, biopiles, and bioreactors. In the last few years, scientific understanding of microbial relations with particular chemicals has aided in the protection of the environment. Despite intensive studies being carried out on the mitigation of toxic pollutants, there have been limited efforts performed to discuss the solutions to tackle the limitations and approaches for the remediation of heavy metals holistically. This paper summarizes the risk assessment of HMs on aquatic creatures, the environment, humans, and animals. The content of this paper highlights the principles and limitations of microbial remediation to address the technological challenges. The coming prospect and tasks of evaluating the impact of different treatment skills for pollutant remediation have been reviewed in detail. Moreover, genetically engineered microbes have emerged as powerful bioremediation capabilities with significant potential for expelling toxic elements. With appropriate examples, current challenging issues and boundaries related to the deployment of genetically engineered microbes as bioremediation on polluted soils are emphasized.

Sustainable strategies for combating hydrocarbon pollution: Special emphasis on mobil oil bioremediation

The global rise in industrialization and vehicularization has led to the increasing trend in the use of different crude oil types. Among these mobil oil has major application in automobiles and different machines. The combustion of mobil oil renders a non-usable form that ultimately enters the environment thereby causing problems to environmental health. The aliphatic and aromatic hydrocarbon fraction of mobil oil has serious human and environmental health hazards. These components upon interaction with soil affect its fertility and microbial diversity. The recent advancement in the omics approach viz. metagenomics, metatranscriptomics and metaproteomics has led to increased efficiency for the use of microbial based remediation strategy. Additionally, the use of biosurfactants further aids in increasing the bioavailability and thus biodegradation of crude oil constituents. The combination of more than one approach could serve as an effective tool for efficient reduction of oil contamination from diverse ecosystems. To the best of our knowledge only a few publications on mobil oil have been published in the last decade. This systematic review could be extremely useful in designing a micro-bioremediation strategy for aquatic and terrestrial ecosystems contaminated with mobil oil or petroleum hydrocarbons that is both efficient and feasible. The state-of-art information and future research directions have been discussed to address the issue efficiently.

Solid waste composition and COVID-19-induced changes in an inland water ecosystem in Turkey

The composition and abundance of solid waste and the effect of COVID-19 measures were studied in an inland water ecosystem in Turkey. Solid waste items were collected annually for 5 years from 2017 to 2021 from seven stations located in Borçka Dam Lake (B1-B4) and Murgul Stream (M1-M3) in the Artvin Province. The highest densities by number and weight were recorded at M3 in 2020 (5.72 items/m²) and M1 in 2020 (0.39 kg/m²), respectively. However, no significant difference in density was recorded (p < 0.05) between the years. Plastic was the most abundant waste material by number of items in all the stations with a percentage contribution varying between 25.47 and 88.89%. There was a considerable increase in medical items during the COVID-19 pandemic in 2020-2021. Nonmetric multidimensional scaling (NMDS) and ANOSIM results revealed visually and statistically significant differences in solid waste composition between the years and stations. The dissimilarity between the years was driven by plastic and medical waste. The main sources of solid waste were river transportation (22.93%), improper disposal (20.74%), aquaculture activities (16.42%), and recreational and tourism activities (14.72%). The results of our study can be a baseline for transportation models, local administrations, and non-governmental organizations. Besides, the current waste management measures in Turkey are not effective in preventing waste accumulation in inland aquatic systems such as the Borçka Dam Lake and Murgul Stream. Furthermore, these findings indicate that the COVID-19 pandemic influenced solid waste composition and increased its abundance in the study area.

Impact of financial inclusion and globalization on environmental quality: evidence from G20 economies

Sustainable development and addressing climate change are among the most pressing issues faced by countries around the world. This research investigates the dynamic associations between financial inclusion, globalization and CO2 emissions of G20 nations from 2005 to 2018, considering the effects of industrial structure, corruption, green energy utilization and economic growth as control variables. In this study, both financial inclusion and globalization index were measured using principal component analysis (PCA). This study examines long-term associations using cross-sectional augmented autoregressive distributed lag (CS-ARDL) technique that offers more accurate outcomes. In addition, the VECM Granger causality method was applied to find causal relationships between study variables. Findings show that in financial inclusion, globalization has positive significant effect on carbon emissions. Moreover, corruption and economic have positive impact on carbon emissions, and renewable energy shows negative impact on environmental quality. The findings of this research are critical for achieving sustainable development and pollution control goals. Governments need to work to bring into line the financial inclusion goals with renewable energy consumption habits and environmental strategies.

Solid waste composition and COVID-19-induced changes in an inland water ecosystem in Turkey

The composition and abundance of solid waste and the effect of COVID-19 measures were studied in an inland water ecosystem in Turkey. Solid waste items were collected annually for 5 years from 2017 to 2021 from seven stations located in Borçka Dam Lake (B1-B4) and Murgul Stream (M1-M3) in the Artvin Province. The highest densities by number and weight were recorded at M3 in 2020 (5.72 items/m²) and M1 in 2020 (0.39 kg/m²), respectively. However, no significant difference in density was recorded (p < 0.05) between the years. Plastic was the most abundant waste material by number of items in all the stations with a percentage contribution varying between 25.47 and 88.89%. There was a considerable increase in medical items during the COVID-19 pandemic in 2020-2021. Nonmetric multidimensional scaling (NMDS) and ANOSIM results revealed visually and statistically significant differences in solid waste composition between the years and stations. The dissimilarity between the years was driven by plastic and medical waste. The main sources of solid waste were river transportation (22.93%), improper disposal (20.74%), aquaculture activities (16.42%), and recreational and tourism activities (14.72%). The results of our study can be a baseline for transportation models, local administrations, and non-governmental organizations. Besides, the current waste management measures in Turkey are not effective in preventing waste accumulation in inland aquatic systems such as the Borçka Dam Lake and Murgul Stream. Furthermore, these findings indicate that the COVID-19 pandemic influenced solid waste composition and increased its abundance in the study area.

Novel insight on ferric ions addition to mitigate recalcitrant formation during thermal-alkali hydrolysis to enhance biomethanation

Thermal-chemical pre-treatment has proven to facilitate the solubilization of organics and improvement in biogas generation from the organic fraction of municipal solid waste (OFMSW). However, the production of recalcitrant is inevitable when OFMSW is pretreated at high temperatures and alkali dosage. This study develops a strategy to use Fe³⁺ to reduce the formation of recalcitrant compounds, i.e., 5-HydroxyMethyl Furfural (5-HMF), furfurals, and humic acids (HA) during thermal-alkali pre-treatment. It was postulated that the formation of the recalcitrant compound during pre-treatment can be reduced by Fe³⁺ dosing to oxidize intermediates of Maillard reactions. A decrease in 5-HMF (45-49%) and furfurals (54-66%) was observed during Fe³⁺ (optimum dose: 10 mg/L) mediated thermal-alkali pre-treatment owing to the Lewis acid behavior of FeCl₃. The Fe³⁺ mediated assays show a substantial improvement in VS removal (28%) and biogas yield, i.e., 31% (292 mL/gVS_added) in 150 °C + 3 g/L NaOH, 34% (316 mL/gVS_added) in 175 °C + 3 g/L NaOH, and 36% (205 mL/gVS_added) in 200 °C + 3 g/L NaOH assays, over their respective controls (no Fe³⁺ dosing). The reducing property of Fe³⁺ rendered a low ORP (-345 mV) in the system than control, which is beneficial to the anaerobic microbiome. Electrical conductivity (EC) also shows a three-fold increase in Fe³⁺ mediated assays over control, promoting direct interspecies electron transfer (DIET) amongst microbes involved in the electrical syntrophy. The score plot and loading plots from principal component analysis (PCA) showed that the results obtained by supplementing 10 mg/L Fe³⁺ at 150, 175, and 200 °C were significantly different. The correlation of the operational parameters was also mutually correlated. This work provides a techno-economically and environmentally feasible option to mitigate the formation of recalcitrant compounds and enhance biogas production in downstream AD by improving the degradability of pretreated substrate.

Sustainable management of municipal solid waste through waste-to-energy technologies

Increasing municipal solid waste (MSW) generation and environmental concerns have sparked global interest in waste valorization through various waste-to-energy (WtE) to generate renewable energy sources and reduce dependency on fossil-derived fuels and chemicals. These technologies are vital for implementing the envisioned global "bioeconomy" through biorefineries. In light of that, a detailed overview of WtE technologies with their benefits and drawbacks is provided in this paper. Additionally, the biorefinery concept for waste management and sustainable energy generation is discussed. The identification of appropriate WtE technology for energy recovery continues to be a significant challenge. So, in order to effectively apply WtE technologies in the burgeoning bioeconomy, this review provides a comprehensive overview of the existing scenario for sustainable MSW management along with the bottlenecks and perspectives.

Biochar production with amelioration of microwave-assisted pyrolysis: Current scenario, drawbacks and perspectives

In recent years, biomass has been reported to obtain a wide range of value-added products. Biochar can be obtained by heating biomass, which aids in carbon sinks, soil amendments, resource recovery, and water retention. Microwave technology stands out among various biomass heating technologies not only for its effectiveness in biomass pyrolysis for the production of biochar and biofuel but also for its speed, volumetrics, selectivity, and efficiency. The features of microwave-assisted biomass pyrolysis and biochar are briefly reviewed in this paper. An informative comparison has been drawn between microwave-assisted pyrolysis and conventional pyrolysis. It focuses mainly on technological and economic scenario of biochar production and environmental impacts of using biochar. This source of knowledge would aid in the exploration of new possibilities and scope for employing microwave-assisted pyrolysis technology to produce biochar.

Carbon-based catalyst for environmental bioremediation and sustainability: Updates and perspectives on techno-economics and life cycle assessment

Global rise in the generation of waste has caused an enormous environmental concern and waste management problem. The untreated carbon rich waste serves as a breeding ground for pathogens and thus strategies for production of carbon rich biochar from waste by employing different thermochemical routes namely hydrothermal carbonization, hydrothermal liquefaction and pyrolysis has been of interest by researchers globally. Biochar has been globally produced due to its diverse applications from environmental bioremediation to energy storage. Also, several factors affect the production of biochar including feedstock/biomass type, moisture content, heating rate, and temperature. Recently the application of biochar has increased tremendously owing to the cost effectiveness and eco-friendly nature. Thus this communication summarized and highlights the preferred feedstock for optimized biochar yield along with the factor influencing the production. This review provides a close view on biochar activation approaches and synthesis techniques. The application of biochar in environmental remediation, composting, as a catalyst, and in energy storage has been reviewed. These informative findings were supported with an overview of lifecycle and techno-economical assessments in the production of these carbon based catalysts. Integrated closed loop approaches towards biochar generation with lesser/zero landfill waste for safeguarding the environment has also been discussed. Lastly the research gaps were identified and the future perspectives have been elucidated.