An evaluation model for city-scale construction and demolition waste management effectiveness: A case study in China.

The growing generation of construction and demolition waste (CDW) has emerged as a prominent challenge on global environmental agendas. However, the effectiveness of CDW management (CDWM) strategies varies among cities. Existing literature predominantly evaluates the effectiveness of CDWM at the project level, offering a localized perspective that fails to capture a city's comprehensive CDWM profile. This localized focus has certain limitations. To fill this gap in city-scale evaluations, this study introduces a novel model for assessing CDWM effectiveness at the municipal level. An empirical investigation was conducted across 11 cities within the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) to operationalize this model. The model defines five distinct levels of CDWM effectiveness. Findings indicate that Hong Kong consistently achieves the highest level (level I), while the majority of cities fall within levels III and IV. This pattern suggests that CDWM effectiveness in the GBA is moderately developed, with uneven progress in CDW management outcomes and supporting systems. Essentially, there is a lack of synchronous development of CDWM results and guarantee systems. The proposed evaluation model enriches existing CDWM research field and offers a framework that may inform future studies in other countries.

Integrating fuzzy-AHP and GIS for solid waste disposal site selection in Kenitra province, NW Morocco.

Selecting an optimal solid waste disposal site is one of the decisive waste management issues because unsuitable sites cause serious environmental and public health problems. In Kenitra province, northwest Morocco, sustainable disposal sites have become a major challenge due to rapid urbanization and population growth. In addition, the existing disposal sites are traditional and inappropriate. The objective of this study is to suggest potential suitable disposal sites using fuzzy logic and analytical hierarchy process (fuzzy-AHP) method integrated with geographic information system (GIS) techniques. For this purpose, thirteen factors affecting the selection process were involved. The results showed that 5% of the studied area is considered extremely suitable and scattered in the central-eastern parts, while 9% is considered almost unsuitable and distributed in the northern and southern parts. Thereafter, these results were validated using the area under the curve (AUC) of the receiver operating characteristics (ROC). The AUC found was 57.1%, which is a moderate prediction's accuracy because the existing sites used in the validation's process were randomly selected. These results can assist relevant authorities and stakeholders for setting new solid waste disposal sites in Kenitra province.

Agricultural Waste Management by Production of Second-Generation Bioethanol from Sugarcane Bagasse Using Indigenous Yeast Strain.

In the wake of rapid industrialization and burgeoning transportation networks, the escalating demand for fossil fuels has accelerated the depletion of finite energy reservoirs, necessitating urgent exploration of sustainable alternatives. To address this, current research is focusing on renewable fuels like second-generation bioethanol from agricultural waste such as sugarcane bagasse. This approach not only circumvents the contentious issue of food-fuel conflicts associated with biofuels but also tackles agricultural waste management. In the present study indigenous yeast strain, Clavispora lusitaniae QG1 (MN592676), was isolated from rotten grapes to ferment xylose sugars present in the hemicellulose content of sugarcane bagasse. To liberate the xylose sugars, dilute acid pretreatment was performed. The highest reducing sugars yield was 1.2% obtained at a temperature of 121 °C for 15 min, a solid-to-liquid ratio of 1:25 (% w/v), and an acid concentration of 1% dilute acid H2SO4 that was significantly higher (P < 0.001) yield obtained under similar conditions at 100 °C for 1 h. The isolated strain was statistically optimized for fermentation process by Plackett-Burman design to achieve the highest ethanol yield. Liberated xylose sugars were completely utilized by Clavispora lusitaniae QG1 (MN592676) and gave 100% ethanol yield. This study optimizes both fermentation process and pretreatment of sugarcane bagasse to maximize bioethanol yield and demonstrates the ability of isolated strain to effectively utilize xylose as a carbon source. The desirable characteristics depicted by strain Clavispora lusitaniae shows its promising utilization in management of industrial waste like sugarcane bagasse by its conversion into renewable biofuels like bioethanol.

Effective food waste management model for the sustainable agricultural food supply chain.

The extensive research examines the current state of agricultural food supply chains, with focus on waste management in Bandung Regency, Indonesia. The study reveals that a significant proportion of food within the agricultural supply chain goes to waste and discusses the various challenges and complexities involved in managing food waste. The research presents a conceptual model based on the ADKAR change management paradigm to promote waste utilization, increase awareness and change people's behaviors. The model emphasizes the importance of creating awareness, fostering desire, providing knowledge, implementing changes, and reinforcing and monitoring the transformation process. It also addresses the challenges, barriers, and drivers that influence waste utilization in the agricultural supply chain, highlighting the need for economic incentives and a shift in public awareness to drive meaningful change. Ultimately, this study serves as a comprehensive exploration of food waste management in Bandung Regency, shedding light on the complexities of the issue and offering a systematic approach to transition towards more sustainable waste utilization practices.

Forecasting municipal solid plastic waste generation and management policy using system dynamics: a case study of Khulna City in Bangladesh.

A comprehensive analysis of municipal solid plastic waste (MSPW) management while emphasizing plastic pollution severity in coastal cities around the world is mandatory to alleviate the augmenting plastic waste footprint in nature. Thus, decision-makers' persuasion for numerous management solutions of MSPW flow-control can be met through meditative systematic strategies at the regional level. To forecast solutions focused on systematic policies, an agent-based system dynamics (ASD) model has been developed and simulated from 2023 to 2040 while considering significant knit parameters for MSPW management of Khulna City in Bangladesh. Baseline simulation results show that per-capita plastic waste generation will increase to 11.6 kg by 2040 from 8.92 kg in 2023. Eventually, the landfilled quantity of plastic waste has accumulated to 70,000 tons within 18 years. Moreover, the riverine discharge has increased to 834 tons in 2040 from a baseline quantity of 512 tons in 2023. So the plastic waste footprint index (PWFI) value rises to 24 by 2040. Furthermore, the absence of technological initiatives is responsible for the logarithmic rise of non-recyclable plastic waste to 1.35*1000=1350 tons. Finally, two consecutive policy scenarios with baseline factors such as controlled riverine discharge, increased collection and separation of plastic waste, expansion of recycle business, and locally achievable plastic conversion technologies have been simulated. Therefore, policy 2, with 69% conversion, 80% source separation, and 50% riverine discharge reduction of MSPW, has been found adequate from a sustainability perspective with the lowest PWFI ranges of 3.97 to 1.07 alongside a per-capita MSPW generation of 7.63 to 10 kg from 2023 till 2040.

Smart regulations in maritime governance: Efficacy, gaps, and stakeholder perspectives.

The paper explores maritime environmental regulations, analyzing industry perspectives and their operational execution. It critically assesses the International Maritime Organization (IMO) regulations' effectiveness in mitigating climate challenges within the shipping domain. The central argument is that the evolving and intricate nature of maritime regulations often impedes policy goal realization, enforcement, impact evaluation, and equity perception. Utilizing both quantitative and qualitative methodologies, this research gathers, analyses, and interprets data via surveys and interviews. This exploration seeks to evaluate the regulations' impact on reducing shipping's negative impact, especially concerning emissions, waste management, and noise pollution, under the umbrella of smart regulations. The results indicate that the current regulatory approach is neither comprehensive nor immediate, necessitating a more agile, digitally enabled framework to adapt to fast-changing industry conditions.

A comprehensive study of food waste management and processing in the Czech Republic: Potential health risks and consumer behavior.

Food waste is currently a widely discussed phenomenon with significant economic and social consequences. One third of the food produced in the world is wasted at various points along the food supply chain. This article presents a comprehensive study that examines consumer behavior in dealing with food waste and activities in the composting process that enable waste sanitation. The survey conducted as part of this study showed that consumers want to eliminate odors, are concerned about potential infections, and generally sort less food waste. This study suggested that the addition of appropriate additives could be a solution. The results indicated that additives could eliminate negative side effects such as unpleasant odors, the presence of insects and rodents, and act as a prevention of the occurrence of pathogenic organisms. Tea tree oil showed the best positive physical and chemical properties among the additives tested (CaCO3 and citric acid) with a significant effect on inhibiting the growth of bacterial strains such as Salmonella strains and had the strongest antibacterial effect, neutralized unpleasant odors, and stabilized the waste. The use of additives could be a future solution to meet consumer demands, improve the quality of food waste and advance the circular economy to improve the sustainability of agricultural systems.

Opportunities and challenges for circular economy in the Maldives: A stakeholder analysis of informal E-waste management in the Greater Malé Region.

In the Maldives, the contribution of the informal sector to e-waste management is significant as a formal e-waste management system is not yet established. The opportunities for advancing the circular economy in the Maldives' e-waste sector rely on the possibility of its formalization. This study aimed to examine the current and anticipated situations of e-waste management in the Greater Malé Region of the Maldives, with a specific focus on formalizing the informal sector. Interviews and questionnaire-based surveys were conducted followed by statistical analysis of the data. The t-test performed for the consumer survey data (n = 202) suggests that formalization encourages consumers to engage with the informal sector, resulting in increased resource recovery. Thematic analysis of interviews conducted with both formal and informal sector stakeholders (n = 17) revealed that the informal sector plays a substantial role in managing e-waste. It also underscored the need for government assistance to enhance safety and productivity in this sector. Various opportunities and challenges for establishing a circular economy in the country were identified, such as the rise in e-waste generation, the presence of an active informal workforce, the lack of sufficient government support, and prevailing stereotypes among consumers regarding informal workers. These findings provide a fresh perspective on the solutions for waste management in the Maldives and open the door to further explore the significance of the informal sector and feasible formalization initiatives. This study could contribute to the literature on the role of the informal sector in waste management in the Maldives and other small island developing states.

Influence of Canadian provincial stewardship model attributes on the cost effectiveness of e-waste management.

This paper presents a comprehensive analysis of e-waste collection and management trends across six Canadian provinces, focusing on e-waste collection rates, provincial stewardship model attributes, program strategies and budget allocations from 2013 to 2020. Temporal and regression analyses were conducted using data from Electronic Product Recycling Association reports. A group characterization based on geographical proximity is proposed, aiming to explore the potential outcomes of fostering collaboration among neighboring provinces. The analysis emphasizes the significant impact of stewardship model attributes on e-waste collection rates, with Quebec emerging as a standout case, showcasing a remarkable 61.5% surge in collection rates. Findings from group analysis reveal a positive correlation between per capita e-waste collection rate and the growth of businesses and collection sites in Western Canada (Group A - British Columbia, Saskatchewan, and Manitoba). This highlights the potential benefits of a coordinated waste management approach, emphasizing the importance of shared resources and collaborative policies. Saskatchewan and Manitoba allocated only 6.6% and 7.0% of their respective budgets to e-waste transfer and storage. British Columbia's observed steady decrease of e-waste collection rate. In Group A, stewards handled 2.18-13.95 tonnes of e-waste during the study period. The cost per tonne of e-waste tended to be lower when more e-waste is managed per steward, suggesting the potential benefits of an integrated e-waste collection and management system.

A review on the evaluation models and impact factors of greenhouse gas emissions from municipal solid waste management processes.

The total amount of global municipal solid waste (MSW) will reach 3.5 billion tons by 2050, thereby bringing tremendous environmental pressure, especially global warming. Large amounts of greenhouse gases (GHGs) have been released during MSW management (MSWM). Accounting for GHG emissions is a prerequisite for providing recommendations on appropriate treatment options to mitigate emissions from MSWM systems. There are many methods involved in estimating emissions. This paper summarizes the computing models commonly used in each process of the integrated MSWM system and emphasizes the influence of parameters and other factors. Compared with other disposal methods, landfilling has the highest emissions, commonly estimated using first-order decay (FOD) methods. Emission reduction can be realized through waste to energy (WtE) and resource recovery measures. IPCC is commonly used for calculating direct emissions, while LCA-based models can calculate emissions including upstream and downstream processes, whose results depend on assumptions and system boundaries. The estimation results of models vary greatly and are difficult to compare with each other. Besides, large gaps exist between the default emission factors (EFs) provided by models and those F measured in specific facilities. These findings provide a systematic view for a bettering understanding of MSW emissions as well as the estimating methods and also reveal the key points that need be developed in the future.

Shrimp Waste Upcycling: Unveiling the Potential of Polysaccharides, Proteins, Carotenoids, and Fatty Acids with Emphasis on Extraction Techniques and Bioactive Properties.

Shrimp processing generates substantial waste, which is rich in valuable components such as polysaccharides, proteins, carotenoids, and fatty acids. This review provides a comprehensive overview of the valorization of shrimp waste, mainly shrimp shells, focusing on extraction methods, bioactivities, and potential applications of these bioactive compounds. Various extraction techniques, including chemical extraction, microbial fermentation, enzyme-assisted extraction, microwave-assisted extraction, ultrasound-assisted extraction, and pressurized techniques are discussed, highlighting their efficacy in isolating polysaccharides, proteins, carotenoids, and fatty acids from shrimp waste. Additionally, the bioactivities associated with these compounds, such as antioxidant, antimicrobial, anti-inflammatory, and antitumor properties, among others, are elucidated, underscoring their potential in pharmaceutical, nutraceutical, and cosmeceutical applications. Furthermore, the review explores current and potential utilization avenues for these bioactive compounds, emphasizing the importance of sustainable resource management and circular economy principles in maximizing the value of shrimp waste. Overall, this review paper aims to provide insights into the multifaceted aspects of shrimp waste valorization, offering valuable information for researchers, industries, and policymakers interested in sustainable resource utilization and waste-management strategies.

Applying social life cycle assessment in the informal recycling sector: Understanding challenges and limitations.

The transition towards Circular Economy (CE) is a promising approach to sustainable development that may cause significant social impacts. Despite the benefits of CE initiatives, key players such as informal recyclers face serious social issues such as poverty, lack of social security, and discrimination. Although evaluating social impacts remains a considerable challenge, Social Life Cycle Assessment (SLCA) is recognized as a suitable methodology with a life cycle perspective. While most SLCA experiences are conducted in the formal sector, it is important to consider the informal sector, which plays a crucial role in developing countries. This article presents an analysis of SLCA studies in informal recycling settings in order to identify the challenges and adjustments required for informal settings. The analysis is based on a literature review and a documentary review of a pilot application of SLCA in the informal recycling system in Cuenca, Ecuador. The results show that SLCA requires adaptation to be applied in informal settings. There are particular challenges in delineating boundaries due to the fuzzy nature and variability of informal activities. Tasks such as establishing specific indicators, developing reference scales and data collection, require careful planning and active stakeholder participation. For instance, indicators regarding Fair Salary or Working hours were adapted based on best practices. Furthermore, tasks such as verifying and disseminating results should be included in interpretation phases to generate long-term impacts and influence behaviors. The study underscores SLCA's multidimensional view but highlights the need for further standardization and adaptation for informal sectors.

Pressurized pyrolysis of mattress residue: An alternative to landfill management.

Mattresses are a difficult waste to manage in landfills due to their large volume and low density. Pyrolysis treatment could reduce its volume while producing fuel or products valuable for the chemical industry. Pressurized pyrolysis at 400, 450, and 500 °C is carried out in a lab-scale autoclave at initial pressures 4.2, 8.4, and 16.8 bar. Product gas yield increases slightly along with elevated pressure as well as temperature. However, beyond 8.4 bar the initial pressure makes no discernible differences. CO and CO2 are the major gas species followed by CH4. CO contributes the most to the product gas energy content followed by C3 species, C2H6, and H2. Calculated energy content (heating value) is between 2 and 15 MJ·Nm-3. In terms of product gas energy content, low pressure pyrolysis is favorable over high pressure pyrolysis. According to integration areas of chromatographic measurements the liquid phase contains up to 25 % of N-compounds, with benzonitrile being the most abundant, followed by toluene, o-xylene, and ethylbenzene. The solid char maintains constant properties across operating conditions, with carbon and energy contents of approximately 75 wt% and 30 MJ·kg-1, respectively.

Mitigating ash-related alkali and heavy metals emissions in rotary kiln through oxygen-carrier-aided combustion of waste.

Rotary kiln (RK) incineration technology gains prominence in waste management, aiming to reduce pollution, recover energy, and minimize waste. Oxygen-carrier (OC)-aided incineration of waste in the RK demonstrates notable benefits by enhancing oxygen distribution uniformity and facilitating fuel conversion. However, the effects of OC on ash-related alkali and heavy metals during waste incineration in the RK remain unknown. In this study, manganese ore and ilmenite as OCs are introduced into RK during waste combustion, focusing on their effects on the bottom ashes and the behavior of alkali and heavy metals. Results show that manganese ore exhibits a decreasing reactivity due to oxygen depletion during the conversion from Mn2O3 to Mn3O4, while ilmenite maintains good reactivity due to sustained enrichment of Fe2O3 on the particles even after multiple cycles in RK. The porous structure on the surface of OCs particles verifies the cyclic reaction involving oxidation by air and reduction by fuel as OCs move between the active and passive layers of the bed. The porous OCs particles offer abundant adsorption sites for K from the gaseous phase, with surface-deposited K migrating into the particles and enhancing the OCs' capacity for K adsorption. Adding OCs promotes the formation of stable, less volatile compounds of heavy metals (As, Cr, Pb, and Zn) and enhances their retention in bottom ash while ensuring the leaching toxicity remains below Chinese national standard limits. This study enhances the understanding of OCs in incineration, guiding vital references for waste management practices and environmental sustainability.

An investigation on the operational resilience of the Canadian electronic product stewardship program and the recycling business characteristics.

Electronic waste recycling companies have proliferated in many countries due to valuable materials present in end-of-life electronic and electrical equipment. This article examined the business characteristics and management performance of Electronic Products Recycling Association (EPRA), a Canadian nationwide electronic product stewardship organization. The organization's annual performance reports, from 2012 to 2020, for nine Canadian provinces in which it currently operates were aggregated and analyzed. Temporal analysis using regression and Mann-Kendall tests were employed, and five characteristics of EPRA's business were analyzed, including e-waste products collected, number of drop-off locations, efforts to build public awareness, operating expenses, and growth of e-waste stewardship. Results show a decline in the amount of e-waste collected across the provinces, except in New Brunswick, which started its program in 2017. The Mann-Kendall test revealed declining temporal trends in most provinces. Although the collection/drop off sites and stewardship organizations increased astronomically over the study period in Canada, the amounts of e-waste collected decreased. We found that public awareness generally did not increase the amount of e-waste collected, and these campaigns only appeared to be effective in jurisdictions with good accessibility of e-waste recycling. Processing cost accounted for the majority of the e-waste management budget in Canada, and different factors affected the financial success of the stewards differently.

Plastic waste management in recycling facilities: Intentionally generated MPs as an emerging contaminant.

There is little knowledge about microplastic (MP) pollution in plastic recycling facility (PRF) wastewater. In this study, MPs in the wastewaters of four PRFs located in Türkiye were characterized for size, shape, color, and polymer types after sieving from 5,000 µm to the lowest 75 µm with seven sieves. The wet peroxide oxidation procedure was applied before attenuated total reflectance fourier transform infrared spectroscopy analysis for polymer identification. Polyethylene, and polypropylene were the dominant (75 % of total count) MP types within 22 polymer types. Average hit qualities of polymers increased from 69 % to above 84 % for the device software (OPUS) and open software (OpenSpecy). The abundance of MPs was determined as 53,987 MPs/L and 0.8 g MP/L for mixed PRFs 7,582 MPs/L and 4.6 g/L for the LDPE recycling facility, and 2,196 MPs/L and 0.06 g MPs/L for the granulation cooling water by count and weight, respectively. Small-sized MPs are found in the bottom sample much more than the surface and effluent samples in the washing tank. This indicated that MPs adsorbed the pollutants settled in the washing tank due to adsorbed pollution/biofilm. A maximum of 4.6 kg MP/ton of plastic recycled can be discharged as MPs that can be recovered. Considering the plastics recycling capacity, discharged MPs in these PRFs are possibly above 30,000 tons.

Precycling in the circular economy: Application of the motivation opportunity ability framework to explore the antecedents of consumers' precycling behavior in Finland.

Dealing with overconsumption and the waste crisis requires consumers to make a drastic lifestyle change, adopting more circular consumption patterns that support the prevention of waste generation. The goal of our study was to explore the range of precycling behaviors aimed at preventing waste generation in households. We tested the hypotheses of the Motivation Opportunity Ability framework using a nationally representative survey of consumers residing in Finland (n = 1,000). Respondents reported a high level of motivation, moderate level of opportunity and ability and engaged in precycling occasionally. Using exploratory factor analysis, we identified three types of precycling behaviors: long-term planning, resourceful behavior, and reuse for circularity. Multiple linear regression indicated that motivation (frugality and minimalism), opportunity (distance to circular economy services), ability (skills related to the circular economy), and precycling were associated. These findings suggest that policymakers need to focus on increasing consumers' precycling skills and improving the accessibility and availability of precycling services.

Multi-objective location-routing optimization based on machine learning for green municipal waste management.

Most of the existing municipal waste management (MWM) systems focus on the optimization of the waste disposal center locations and waste collection paths, which can be modeled based on the location-routing problem (LRP). This study models a green MWM system by a three-objective location-routing problem to achieve equilibrium among the total cost, carbon emission, and residential satisfaction. The amount of waste demand for each customer is considered as an independent discrete random variable following a normal distribution. The multi-objectives and non-deterministic characteristics make this problem more intractable than the traditional LRP. A multi-objective optimization algorithm based on decision tree classifier is proposed for solving this problem. The decision tree classifier learns from previous searching experience, and then guides the following evolution process to avoid blind searching. The experimental results show that the proposed algorithm has high competitiveness compared with other state-of-art methods. A case study is also conducted for a real waste collection problem in a certain area of Beijing. The proposed method adopts efficient location-routing strategies to balance the total cost, carbon emissions, and distance between residential areas and waste disposal centers.

What shapes food waste behaviors? New insights from a comprehensive action determination model.

The sharp increase in food waste poses a serious threat to food security and environmental sustainability. However, most existing studies have investigated the determinants of food waste behaviors in a separate behavioral process without considering the potential impacts of different factors in an integrated process. To narrow this gap, a comprehensive action determination model (CADM), which integrates network embeddedness and incentive measures, was constructed to explore the impact of various determinants in different processes on food waste behaviors, using data collected from 913 residents in eastern China via an online survey. The empirical results showed that environmental concern was the largest positive factor in predicting personal norms (ß = 0.80, p < 0.001), followed by network embeddedness. With the habitual process considered, residents with ingrained waste habits were more likely to waste food (ß = 0.38, p < 0.001). Moreover, the normative process alleviates behavioral decisions via intentions to reduce food waste. This study confirmed the differences in the situational process and suggested that menu tips increase food waste behaviors, while incentive measures reinforce the influence of intentions on behavior. We therefore address the insufficient ingredients on the effects of different processes on behavior and provide a new perspective for formulating behavioral intervention policies.

Compression stress-strain curve of lithium slag recycled fine aggregate concrete.

As one of the key materials used in the civil engineering industry, concrete has a global annual consumption of approximately 10 billion tons. Cement and fine aggregate are the main raw materials of concrete, and their production causes certain harm to the environment. As one of the countries with the largest production of industrial solid waste, China needs to handle solid waste properly. Researchers have proposed to use them as raw materials for concrete. In this paper, the effects of different lithium slag (LS) contents (0%, 10%, 20%, 40%) and different substitution rates of recycled fine aggregates (RFA) (0%, 10%, 20%, 30%) on the axial compressive strength and stress-strain curve of concrete are discussed. The results show that the axial compressive strength, elastic modulus, and peak strain of concrete can increase first and then decrease when LS is added, and the optimal is reached when the LS content is 20%. With the increase of the substitution rate of RFA, the axial compressive strength and elastic modulus of concrete decrease, but the peak strain increases. The appropriate amount of LS can make up for the mechanical defects caused by the addition of RFA to concrete. Based on the test data, the stress-strain curve relationship of lithium slag recycled fine aggregate concrete is proposed, which has a high degree of agreement compared with the test results, which can provide a reference for practical engineering applications. In this study, LS and RFA are innovatively applied to concrete, which provides a new way for the harmless utilization of solid waste and is of great significance for the control of environmental pollution and resource reuse.