An overview of municipal solid waste management in China

Solid Waste Generation Rate, Composition Analysis, and Proposed Management Plan: A Case Study of Main Market Centers of Bahir Dar City

Effective municipal solid waste management is a critical aspect of urban development. This study investigated the waste generation rate, composition, and current solid waste management plan in Bahir Dar City, Ethiopia. A two-stage random sampling technique was implemented. Data collection involves onsite data collection, structured questionnaires, and semistructured interviews. The result indicated that retail trade emerges as the leading sector, generating nearly half of the total solid waste (49%), and the food service sector stands second. In terms of solid waste type, food waste constitutes a significant portion of the waste stream, with a daily generation of 10,817.51 kg. The paper and cardboard waste in the market centers were the second waste, accounting for 762.684 kg per day. The amount of plastic waste generated per day ranges from 157.946 to 493.253 kg, and because of its high volatile matter content (68.95%), it might be used to produce energy. Food waste and yard waste had a high moisture content of 63.25% and 40.14%, respectively, which makes them ideal for composting and biogas production. Among the seven study sites, Kebele 04 had a huge waste generation, which was 47% of the total waste generation, indicating a spatial disparity in waste production in the city. The results highlighted the immense potential for waste reuse and recycling, emphasizing the circular economic opportunities associated with sustainable waste management practices. The findings contribute valuable insights to urban planners and policymakers to implement sustainable solid waste management plans in the country.

Four-decades evolutionary development of municipal solid waste management in China: Implications for sustainable waste management and circular economy

This study collected data on waste generation and management in China between 1979 and 2020 from government statistics and literature and reviewed the development of municipal solid waste (MSW) management in China. The extended stochastic impact by regression on population, affluence and technology (STIRPAT) model was employed to identify the driving forces of MSW generation, and the cointegration analysis showed that economy (0.35, t = -3.47), industrial structure (3.34, t = -20.77) and urbanization (-1.5, t = 5.678) were the significant socioeconomic driving forces in the long run. By employing the framework of evolutionary economics, this study then investigated the internal rules of long-term interaction between socioeconomic factors and MSW management. The results indicate that, in the long run, MSW management development can be viewed as an evolutionary process that includes a continuous adaptation to external socioeconomic factors and the co-evolution of internal institutions and technologies. Adaptation and diversity of institutions and technologies play an important role in achieving sustainable waste management and circular economy (CE). This study offers a novel evolutionary perspective for explaining dynamic changes of MSW management in China, as well as recommendations for emerging economies to achieve sustainable waste management and CE goals.

Innovative biogas energy system: Enhancing efficiency and sustainability through multigeneration integration

This research suggests using landfill gas, derived from landfilling operations, as a feasible alternative to fossil fuels. This study introduces a novel and all-encompassing method for utilizing landfill biogas. The proposed system utilizes a supercritical Brayton cycle with carbon dioxide as the working fluid, a transcritical CO2 cycle, two ammonia Rankine cycles, a single-effect desalination cycle, a proton exchange membrane electrolyzer, and an improved Kalina cycle. The system underwent evaluation using Aspen HYSYS software, enabling assessments in terms of energy, exergy, thermo-economic, and environmental variables. The examination of the findings indicates that the suggested solution has much higher energy efficiency compared to similar studies. The assessments determined the energy efficiency of the process in power generation, combined heat and power, combined cooling, heat and power, and multigeneration modes to be 23.62 %, 80.89%, 81.19%, and 82.72%, respectively. Furthermore, environmental research has revealed that the new process emits a total of 1743 kg/h of carbon dioxide and has an emission rate of 0.23 kg/kWh. The exergy analysis indicated that the fuel burner exhibited the greatest degree of irreversibility, accounting for 40%. Furthermore, a sensitivity analysis was performed on crucial parameters, including the temperature of the heat source in the single-effect desalination section and the rate at which water flows into the electrolyzer. The objective was to evaluate the influence of changes in these parameters on energy efficiency, exergy efficiency, carbon dioxide emission intensity, product production rate, and levelized energy cost. The economic analysis determined that the proposed scheme would have a total annual cost of 8,667,124 $ with a levelized energy cost of 0.17 $/kWh.

Essential role of composting industry in achieving China's dual-carbon goals: Case studies from Chinese composting companies

Composting is one of the primary methods for organic waste recycling in China. This study aims to analyze the product quality of organic fertilizer enterprises from the perspective of actual production and the relationship between production process variations and organic matter content in organic fertilizers based on 348 samples from 229 organic fertilizer companies across 22 provinces. Results showed that fertilizers produced through composting processes contain higher organic matter, averaging 45.42 %, compared to commercial organic fertilizers and bio-organic fertilizers. Raw materials, equipment, methods, operational scale, and personnel structure are key factors affecting the content of organic matter in products. Optimizing equipment and processes in Chinese organic fertilizer companies could increase organic matter content to 49.3 %, potentially reducing annual carbon emissions by an estimated 3.07 to 6.97 billion kg of CO2 equivalent, thereby supporting the realization of dual carbon goals.

Release characteristics of volatile organic compounds at residential garbage collection points: a case study of Hangzhou, China

With the implementation of garbage classification, perishable waste has become increasingly concentrated. This has led to a significant change in the VOC release characteristics at residential garbage collection points, posing a potential risk with unknown characteristics. This study investigated the release characteristics, odor pollution, and health risks of VOCs at garbage collection points under different classification effectiveness, seasons, garbage drop-off periods, and garbage collection point types. The results showed that the average concentration of VOCs released from the garbage sorting collection points (SPs) was 341.43 ± 261.16 μg/m3, and oxygenated compounds (e.g., ethyl acetate and acetone) were the main VOC components. The VOC concentration increased as the community classification effectiveness improved, and it was higher in summer (followed by spring, autumn, and winter). Moreover, the VOC concentrations were higher in the evenings than in the mornings and at centralized garbage collection points (CPs) than at SPs. Further, odor activity value (OAV) assessments indicated that acrolein, styrene, and ethyl acetate were the critical odorous components, with an average OAV of 0.87 ± 0.85, implying marginal odor pollution in some communities. Health risk assessments further revealed that trichloroethylene, benzene, and chlorotoluene were the critical health risk substances, with an average carcinogenic risk (CR) value of 10-6-10-4, and a non-carcinogenic risk (HI) value < 1. These results indicated that HIs were acceptable, but potential CRs existed in the communities. Therefore, VOC pollution prevention and control measures should be urgently strengthened at the garbage collection points in high pollution risk scenarios.

A game-theoretic approach to promoting waste management within the framework of a circular economy: implications for environmental protection

Currently, waste management classification is a critical topic that concerns not only environmental protection, but also the advancement of a circular economy. To address this issue within the context of a circular economy, this study develops an uncooperative triumvirate paradigm consisting of "central regulation, local promotion, and universal participation." The model analyzes the strategy choices of both the central and local governments while using an evolutionary game method to encourage residents to promote waste separation. Using numerical simulations, this study examines the variables that impact the strategy choices of the three parties over time. The results show that (1) the desire of the central government, local governments, and citizens to engage has varying effects on each of these entities; the conduct of local government is significantly influenced by the preparedness of the central government, but residents' behavior is comparatively less influenced by the central government's intention; in comparison, it is mainly affected by psychological expectations of income and expenditure; (2) the impact of the local government and residents on each other is characterized by an unbalanced relationship, with the local government being more sensitive to residents' willingness to participate and changes in policy support being more sensitive; and (3) residents show more sensitivity to incentive funds, compensation, penalties, and benefit distribution coefficients. To promote waste separation in China, it is crucial to establish a reasonable expectation of ecological civilization, establish an efficient mechanism for environmental protection supervision, refine local waste separation programs, increase local governments' responsibility for promoting them, ensure legal methods for universal participation, and improve the regulatory mechanism for universal participation to protect the environment. In addition, it is essential to improve the education system for waste separation and continue research related to waste separation.

Spatio-temporal evolution and the driving factors of municipal solid waste in Chinese different geographical regions between 2002 and 2020

Urbanization and economic development have contributed to the rapid and massive generation of municipal solid waste (MSW) and significant changes in spatial patterns, which are becoming a serious pollution problem. Previously, macroscopic studies on the driving factors of MSW have been widely conducted at the national level, but the exploration of the driving factors in different geographical regions on a regional scale has not received much attention in the previous literature. This study is based on China, spatial patterns were analyzed using spatial autocorrelation and movement of center of gravity, and time series clustering was used to explore temporal trends. Subsequently, Geodector was adopted to quantify the relationship between MSW generation and driving factors. The results of the study are as follows: 1) By analyzing the spatial pattern of MSW, this study found that MSW showed a spatial pattern of high in the southeast and low in the northwest during 2002-2020, and its separating line was the same as the Hu-line; the average center of gravity of MSW generation in the past 20 years was always located in Henan Province and shifted southward by 339.7 km. 2) The local spatial autocorrelation analysis results showed that the Low-Low clusters moved from southeast to northwest from 2002 to 2020, increasing to 20 cities. High-High clusters mainly appeared in the East Coast and South Coast regions, increasing from 8 to 17 cities in the last 20 years. 3) The analysis of driving factors by Geodetector revealed that Urbanization is the most critical dimension factor influencing MSW generation, with the strongest impact on the East Coast region. The next dimension is Economy, which has the most significant impact on MSW generation in the North West region. Energy is the third dimension that influences MSW generation, with the greatest impact on the North Coast region. The results of this study reveal trends in the spatial and temporal distribution of MSW in different geographic regions of China over the past 20 years and the impact of their driving factors, which can help the Chinese government take action to control MSW in a site-specific manner.

Municipal solid waste management with recyclable potential in developing countries: Current scenario and future perspectives

Municipal solid waste (MSW) is a complex challenge to be solved worldwide, intensified in developing countries since in addition to economic and environmental aspects there is also the social aspect represented by the collector individual. From an integrative bibliographic review this study longitudinally analyses the socio-productive inclusion of collectors in the municipal solid waste management (MSWM) at an international level. Aiming: (a) to identify relevant articles describing/studies on MSWM with social inclusion of scavengers around the world; (b) to analyse these articles in order to present its main characteristics; (c) to describe municipal solid waste management with recyclable potential (MSWRP) with socio-productive inclusion of collectors; (d) the study provides a more detailed summary of MSWRP management in some developing countries: Brazil, China, India, Indonesia, Mexico, Nigeria and Pakistan; and (e) to provide a framework indicating the future practices and perspectives of MSWRP. As result, this study presents the paradigms and future questions for an effective improvement of WSWM, such as: Professional Training of Scavengers, Cultural Issues, Empowerment of Scavenger, Recycling Cooperatives and Cooperativism, Policy Issues and Recycling Chain, Management Systems and Process Improvement, Quality of Services Provided, Circular Economy and Informal Sector, Health Quality and Safety at Work, Barriers and Solutions for the Inclusion of the Informal Sector, Environmental, Economic and Social Benefits.

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.

Curbing dioxin emissions from municipal solid waste incineration: China's action and global share

China generates the world's second-largest amount of municipal solid waste (MSW) and incinerates the largest quantity of MSW. However, data on the latest dioxin emissions from MSW incineration (MSWI) and the related global share were lacking. In the context of MSW classification, distinguishing the long-term MSW generation and incineration quantity, and dioxin emissions was necessary for macro-control and policy-making by the Chinese Government. By considering population size and GDP per capita, China's MSW generation toward 2050 was projected based on Monte Carlo simulation. Moreover, dioxin emission factors were also assumed based on the diffusion rate of four grades of air pollution control devices (APCDs). Finally, we show that the quantity of China's MSW generation in 2050 will be 363.50 million tonnes (Mt) with 341.06-382.45 Mt of 75% certainty. China's dioxin emissions from MSWI were approximately 15.46 g I-TEQ in 2019, which accounted for 26.1% of total emissions from global MSWI. We discuss dioxin emission reduction scenarios depending on MSW diversion and APCD upgrades. China's dioxin emissions will be 70.38 g I-TEQ for the business-as-usual scenario, and the dioxin emissions will be 9.29 g I-TEQ (within the range of 8.88-9.64 g I-TEQ) for the optimal scenario in 2050. Moreover, in 2050, the APCD diffusion rate will account for 98.8% of the sensitivity of dioxin emissions from China's MSWI. According to the assumed scenarios, there is a dioxin emission reduction potential of 18.6% and 86.8% in 2050 by MSW diversion alone and maximum APCD upgrades combined with food waste diversion, respectively.

An overview study on management and implementation of WEEE in China

Waste electrical and electronic equipment (WEEE) which contains various valuable and harmful materials is an inevitable waste in modern society. In order to resolve the pollution problems associated with WEEE treatment, a WEEE management system has been established in China. The main role of importers and manufacturers of electrical and electronic equipment (EEE) is to pay the treatment fees to facilitate the WEEE recycling in China. The announced treatment and subsidy fee is given by set, not by the weight of WEEE. There is no lesser green treatment fee for the producers which can produce environmentally friendly EEE in China. Also, the recovery of refrigerants from the foaming agent of refrigerators is not required in China. In total, 45 million sets of recycled WEEE were certified in 2020, a year that contains the most updated data. Among them, 48%, 14%, 20%, 10% and 8% are for TV, refrigerator, washing machine, computer and air conditioners, respectively. The spatial analysis indicates that the WEEE recycling activities are mainly concentrated on the mid-east and east regions of China. It also can be concluded that the certified amount of each province has higher positive correlation with provincial population than provincial GDP per capita and green recovery rate. It also clearly notes that the amount of recycled air conditioner is the lowest for each province. Thus, more effort should be conducted to increase the recycling of scrapped air conditioner in China.

Determinants of Satisfaction with Solid Waste Management Services: A Central-Local Comparison in China

The Chinese central government proclaimed a mandatory or demonstration waste separation policy in some cities or counties to manage the increasing amounts of generated waste since 2017. Many cities and regions have also begun to build waste separation management systems and institutions, and community managers have created waste management rules and provided separation management services under the guidance of local government. However, little is known about how these policies or services have performed and the degree of residents’ satisfaction, especially regarding the central government. Therefore, the purpose of this study was to analyze the consequence of these policies using residents’ community and national satisfaction levels with solid waste management services (SWMS) and their determinants. An online survey in 2021 showed that the overall satisfaction levels of communities and national SWMS are similar, but the differences between rural and urban regions are significant. Residents’ satisfaction with community SWMS in urban regions was higher than national satisfaction, and the results in rural regions was contrary. The determinants of community and national satisfaction were also different and varied by region. To improve satisfaction, the government need to standardize basic management systems in different types of regions, gradually improve management services and institutions in rural areas and non-pilot cities and provide special services or facilities for less healthy residents.

An effective system for recovering recyclable waste from households in China: Ant Recovery's bottom-up scheme in Changchun city

In light of China's rising environmental governance focus on household waste recycling, this article analyses a novel recyclable waste recovery scheme, Ant Recovery, in Changchun, Jilin Province. In contrast to other recyclable waste collection systems, Ant Recovery emerged as a bottom-up venture established by members of the informal recycling sector in cooperation with the local recycling association. To assess the scheme's performance, the analysis uses field research data obtained over 21 days of observatory and questionnaire surveys at one of Ant Recovery's mobile collection points. Based on data from 1,501 documented recyclable waste transactions, the analysis indicates a median recovery rate of 438.4 kg/hour at the surveyed recovery station. Extended to the entire scheme's network in Changchun, the figure extrapolates to 2,034.6 metric tons/day, which approximates to roughly 94% of waste recyclables generated by the city's households. These achievements essentially result from two factors: (1) A beneficial policy environment established by central and local regulations and (2) AR's operational compatibility with daily routines and profit orientation of waste recyclable delivering stakeholders. In comparison to many other recycling systems in China, the alternative model in Changchun appears to be indigenous with little requirement for novel organisational structures or high capital/ overhead costs.

Decomposition analysis of the decoupling and driving factors of municipal solid waste: Taking China as an example

As one type of debt 'borrowed' from nature, municipal solid waste (MSW) can be influenced by financing debt. Taking China as an example, an improved Logarithmic Mean Divisia Index (LMDI) model, together with the Tapio decoupling model, is developed to analyze the impact of private debt on MSW generation and the relationship between MSW and economic growth. The results show that the debt-income ratio promotes MSW generation and the output efficiency of debt inhibits MSW generation. Second, the linkage relationship between GDP growth and MSW shows three states: strong decoupling, expansion coupling and weak decoupling. The MSW generation per unit of GDP and the output efficiency of debt are the main contributors to the change of decoupling state. Third, implementing a MSW classification measure can greatly reduce the quantity of MSW removed and transported and improve the decoupling state. By 2035, deleveraging scenario and economic growth slowdown scenario can reduce MSW removal and transportation quantities by 765 and 1080 million tons, respectively. It is worth noting that negative population growth worsens decoupling while curbing MSW. The results provide a new perspective for the realization of MSW reduction and some sound policies are formulated to improve MSW management.

Source separation, transportation, pretreatment, and valorization of municipal solid waste: a critical review

Waste sorting is an effective means of enhancing resource or energy recovery from municipal solid waste (MSW). Waste sorting management system is not limited to source separation, but also involves at least three stages, i.e., collection and transportation (C&T), pretreatment, and resource utilization. This review focuses on the whole process of MSW management strategy based on the waste sorting perspective. Firstly, as the sources of MSW play an essential role in the means of subsequent valorization, the factors affecting the generation of MSW and its prediction methods are introduced. Secondly, a detailed comparison of approaches to source separation across countries is presented. Constructing a top-down management system and incentivizing or constraining residents' sorting behavior from the bottom up is believed to be a practical approach to promote source separation. Then, the current state of C&T techniques and its network optimization are reviewed, facilitated by artificial intelligence (AI) and the Internet of Things technologies. Furthermore, the advances in pretreatment strategies for enhanced sorting and resource recovery are introduced briefly. Finally, appropriate methods to valorize different MSW are proposed. It is worth noting that new technologies, such as AI, show high application potential in waste management. The sharing of (intermediate) products or energy of varying processing units will inject vitality into the waste management network and achieve sustainable development.

A Systematic Literature Review for the Recycling and Reuse of Wasted Clothing

With the growing frequency and quantity of clothing purchases, the elimination rate of waste clothing is increasing. Many researchers have contributed to the topic of the recycling and reuse of waste clothing, and therefore many related literature reviews are emerging. The current reviews only focus on waste textile recycling and waste-clothing life-cycle evaluation. The topic of waste-clothing recycling itself is ignored. In this article, we propose a systematic review of the recycling and reuse of wasted clothes. Firstly, we summarize the existing methods of waste-clothing collection and recycling and the related recycling technology, and discuss their advantages and disadvantages. The involved literatures are journal articles, book chapters, and conference papers selected from Google Scholar and Web of Science. Citespace software, as a literature visualization tool is used for the analysis. Based on this review, the low efficiency of waste-clothes recycling can be attributed to poor organization from a management aspect. From a consumer perspective, because of the differences in understanding among consumers about waste-clothing recycling, the existing clothing-recycling system cannot be fully utilized. The results of this review provide reference for further research on waste-clothing recycling, and make suggestions for the relevant governmental/industrial development strategies.

Fate of dioxins in a municipal solid waste incinerator with state-of-the-art air pollution control devices in China

The variation of municipal solid waste (MSW) components and the improvement of incinerators have an obvious effect on dioxin emissions. However, there is a knowledge gap on dioxin distribution characteristics following China's implementation of MSW classification. To reveal the fate of dioxins under ultra-low emission standards in leading cities in China, a systematic investigation was carried out in a typical modern MSW incinerator in Shenzhen, China. The dioxin mass balance was built using improved models, which included expanded samples, e.g., the leachate, the raw gas and raw ash from boiler, and the chemicals and residuals from air pollution control devices (APCDs). The results indicated a positive dioxin balance of 0.88 μg I-TEQ/t MSW according to the conventional method containing fly ash, bottom ash, and stack gas. In the new model revealing dioxin characteristics after APCDs, a higher value of 0.89 μg I-TEQ/t MSW was found due to the leachate, slaked lime, and activated carbon-containing dioxins. The distribution of dioxins in output samples of fly ash, bottom ash, stack gas, and leachate were 149.0 %, 41.8 %, 1.6 %, and 0.6 % of MSW, respectively. For incineration itself, the balance was 0.85 μg I-TEQ/t MSW, which indicated the possible release owing to the "memory effect" for the other two methods. This study provided new insight for the accurate estimation of dioxin emissions and a typical case report of MSW incineration with ultra-low dioxin emissions.

Potential climate benefits of reusable packaging in food delivery services. A Chinese case study

In China, the food delivery packaging waste is increasing due to the rapid growth of the sector and the use of single-use packaging to transport the meals. In addition, the recycling rates of current municipal waste management are low. In this regard, this study aims at estimating the climate change impact of current food delivery packaging and its waste treatment, by performing a Life Cycle Assessment with a cradle-to-grave approach. In addition, this article explores the potential benefits of increasing the current recycling rates, the recycled content of the packaging as well as the use of reusable packaging. For this study, the food packaging of a typical dumpling-based meal of the popular Chinese restaurant Xijiade was selected. Based on this menu and the current Chinese consumption patterns, the food delivery packaging in China would have emitted about 13 million tons of CO₂eq. Increasing current recycling rates to 35% would reduce 16% the emissions of single-use packaging, and further decrease (60%) could be found if half of the packaging was made of recycled material. In addition, if single-use packaging was replaced by reusable PP-based packaging (food container and carrier bag), the emissions would potentially be 63% lower than the current situation. In this case, doubling the recycling rates and the recycled content of the reusable food packaging would represent an extra 6 and 17% reduction of emissions, respectively.

A circular economy model for waste management in India

Management of waste is one of the major challenges faced by many developing countries. This study therefore attempts to develop a circular economy (CE) model to manage wastes and closing the loop and reducing the generation of residual wastes in Indian municipalities. Through extant literature review, the researchers found 30 success factors of CE implementation. Using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) SIMOS approach, the rating and weight of decision makers (DMs) for each factor were collected. A structured questionnaire has been developed incorporating all these 30 factors, to extract the most important factors. The data was collected from top 10 officials (DMs) from the Chennai municipality, who handle three regions (metropolitan, suburbia and industrial). Based on the TOPSIS SIMOS analysis, nine CE implementing factors (critical success factors (CSFs)) among the 30 variables that were significant based on the cut-off value was identified. A CE model has been proposed based on these nine CSFs for waste management in India.

Building new paths for responsible solid waste management

The amount of solid waste produced across the planet in the past decade was 1.3 billion tons (1.2 kg/year per person). Also, the significant number of publications on solid waste management (SWM) draws attention to the importance of discussing the topic to improve public health and to mitigate environmental impacts. The objectives of this article are to identify the state of the art and the scientific gaps on SWM and to propose a framework to promote it in the coming years. For this, a content analysis was carried out with the support of a bibliometric study, considering articles published in the Scopus database. The field of SWM study was classified into 12 different themes, and from this division, it was sought to identify the evolution of each of them between the 2005 and 2018 period. Content analysis and bibliometric study indicate that thermal and biological treatments are a promising trend to improve the performance of SWM. Its most important applied contribution is the generation of qualified information about SWM that can support the decision-making of public and private managers to reduce environmental impacts and improve life in urban spaces. The main academic contribution of the paper is the articulation of the most important themes on SWM, identifying the individual impact of each one of them in this field of study and the indication of the scientific trends that should guide the development of future research.

COVID-19 and municipal solid waste (MSW) management: a review

Municipal solid waste (MSW) represents an inevitable by-product of human activity and a major crisis for communities across the globe. In recent times, the recycling of MSW has drawn attention as the process can add value through resources from the recovered waste materials and facilitates the process of circular economy. However, during the unprecedented coronavirus (COVID-19) outbreak, the risk of infection with the highly contagious virus has proven detrimental to the continuation of MSW as a valuable resource. The volume of waste, especially household waste, is higher; face masks, PPE (personal protective equipment), and hazardous materials such as batteries and empty chlorine bottles are examples of extra waste that have arisen during the pandemic. Various countries have set up initiatives for MSW management, including safety measurements for employees in the MSW management sector. The use of disinfectant prior to sorting waste, as well as storing waste for 9 days, may help to inactivate the COVID-19 virus, ensuring an appropriate safety level for MSW management. This work aimed at studying different MSW management strategies, specific challenges, and possible solutions for better understanding for those involved in waste management, in addition to providing a possible management strategy during and post-COVID-19 pandemic.

A societal transition of MSW management in Xiamen (China) toward a circular economy through integrated waste recycling and technological digitization

Recently Xiamen (China) has encountered various challenges of municipal solid waste management (MSWM) such as lack of a complete garbage sorting and recycling system, the absence of waste segregation between organic and dry waste at source, and a shortage of complete and clear information about the MSW generated. This article critically analyzes the existing bottlenecks in its waste management system and discusses the way forward for the city to enhance its MSWM by drawing lessons from Hong Kong's effectiveness in dealing with the same problems over the past decades. Solutions to the MSWM problem are not only limited to technological options, but also integrate environmental, legal, and institutional perspectives. The solutions include (1) enhancing source separation and improving recycling system; (2) improving the legislation system of the MSWM; (3) improvement of terminal disposal facilities in the city; (4) incorporating digitization into MSWM; and (5) establishing standards and definitions for recycled products and/or recyclable materials. We also evaluate and compare different aspects of MSWM in Xiamen and Hong Kong SAR (special administrative region) under the framework of 'One Country, Two Systems' concerning environmental policies, generation, composition, characteristics, treatment, and disposal of their MSW. The nexus of society, economics of the MSW, and the environment in the sustainability sphere are established by promoting local recycling industries and the standardization of recycled products and/or recyclable materials. The roles of digitization technologies in the 4^th Industrial Revolution for waste reduction in the framework of circular economy (CE) are also elaborated. This technological solution may improve the city's MSWM in terms of public participation in MSW separation through reduction, recycle, reuse, recovery, and repair (5Rs) schemes. To meet top-down policy goals such as a 35% recycling rate for the generated waste by 2030, incorporating digitization into the MSWM provides the city with technology-driven waste solutions.

Effects of improved information and volunteer support on segregation of solid waste at the household level in urban settings in Madhya Pradesh, India (I-MISS): protocol of a cluster randomized controlled trial

BACKGROUND

Segregation of household waste at the source is an effective and sustainable strategy for management of municipal waste. However, household segregation levels remain insufficient as waste management approaches are mostly top down and lack local support. The realisation and recognition of effective, improved and adequate waste management may be one of the vital drivers for attaining environmental protection and improved health and well-being. The presence of a local level motivator may promote household waste segregation and ultimately pro-environmental behaviour. The present cluster randomized control trial aims to understand if volunteer based information on waste segregation (I-MISS) can effectively promote increased waste segregation practices at the household level when compared with existing routine waste segregation information in an urban Indian setting.

METHODS

This paper describes the protocol of an 18 month two-group parallel,cluster randomised controlled trialin the urban setting of Ujjain, Madhya Pradesh, India. Randomization will be conducted at ward level, which is the last administrative unit of the municipality. The study will recruit 425 households in intervention and control groups. Assessments will be performed at baseline (0 months), midline (6 months), end line (12 months) and post intervention (18 months). The primary outcome will be the comparison of change in proportion of households practicing waste segregation and change in proportion of mis-sorted waste across the study period between the intervention and control groups as assessed by pick analysis. Intention to treat analysis will be conducted. Written informed consent will be obtained from all participants.

DISCUSSION

The present study is designed to study whether an external motivator, a volunteer selected from the participating community and empowered with adequate training, could disseminate waste segregation information to their community, thus promoting household waste segregation and ultimately pro-environmental behaviour. The study envisages that the volunteers could link waste management service providers and the community, give a local perspective to waste management, and help to change community habits through information, constant communication and feedback.

TRIAL REGISTRATION

The study is registered prospectively with Indian Council of Medical Research- Clinical Trial Registry of India ( CTRI/2020/03/024278 ).

Moderating Effects on Residents’ Willingness in Waste Sorting to Improve Waste Handling in Dammam City, Saudi Arabia

While the total amount of municipal solid waste (MSW) in Dammam city was about 13 million tons in 2013, it is expected to reach about 18.4 million tons in 2025. Although the main problem in Dammam city is an increase in solid waste production without any formal treatment except landfilling, the lack of waste segregation greatly affects the residents’ handling practices of solid waste due to incorrect disposing practices. The objective of this study explored the possibility of Dammam residents’ participation in sorting and recycling to improve MSW handling and to measure the influence of psychological factors which affecting residents’ willingness to participate in waste handling regarding socioeconomic levels and moderating effects. This study also examined various respondents’ perspectives on sorting and recycling sustainable waste and the handling of waste generation. This study covered most Dammam communities, with a gender distribution of 56% males and 44% females and the monthly income ranging from SR700 to SR12,000. The descriptive analysis showed that of the 450 participants, 170 (37.8%) were in the middle-income levels, 199 (44.2%) were in the high-income levels and 81 (18%) were in the low-income levels. The moderating effect of income was observed between attitude and willingness to sort and recycle waste in the low-income levels and high-income levels groups. Additionally, an association was found between market incentives and willingness to sort and recycle waste in the low-income levels and high-income levels groups. The gender status of the participants had a moderating effect on the relationship between market incentives and willingness to sort and recycle waste in males and females. Additionally, the moderating effect of social influence on households’ willingness to sort and recycle waste was moderated by gender in males and females.

Does Environmental Policy Help Green Industry? Evidence from China's Promotion of Municipal Solid Waste Sorting

As municipal solid waste severely threatens human health and the ecological environment, since 2019, China has started to fully practice MSW sorting in all prefecture-level cities. In this paper, we apply the event study and difference-in-difference methods to investigate how China’s green policy of promoting MSW sorting influences listed waste sorting companies from the perspective of investors’ short-term and long-term reactions. This paper finds that investors are not sensitive to the introduction of MSW sorting in the short term, the new environmental policy does not relieve the financing constraints of related enterprises in the long run, and the financing constraints of private enterprises are stricter than those of state-owned enterprises. These findings indicate that China’s current encouragement of garbage sorting is not efficient enough as it has not brought benefits to the waste classification industry yet. More measures need to be taken to eliminate uncertainties in urban waste sorting. Our paper enriches the research on China’s waste sorting practices and provides new evidence of the effects of environmental policy on related firms from the perspective of green industry.

Incineration Fly Ash and Its Treatment to Possible Utilization: A Review

Incineration has gained popularity over landfill as a key solution for the reduction of massively increasing volumes of municipal solid waste (MSW) generation worldwide and in particular China. However, it is not the end solution. The disposal of the incineration residues, which are enriched with a wide range of heavy metals and soluble salts, has become a challenge for the environmental managers. The aim of this study was to review the increasing urbanization and its repercussion on waste generation in China; waste management options were compared for possible environmentally friendly considerations. Treatment techniques of incineration fly ash were discussed to determine the effectiveness of obtaining environmentally stable material, and, finally, possible applications of incineration fly ash for utilization were discussed based on identifying the processing suitability, performance and environmental impact of incineration fly ash for its applications.

Estimating Physical Composition of Municipal Solid Waste in China by Applying Artificial Neural Network Method

Physical composition of municipal solid waste (PCMSW) is the fundamental parameter in domestic waste management; however, high fidelity, wide coverage, upscaling, and year continuous data sets of PCMSW in China are insufficient. A traceable and predictable methodology for estimating PCMSW in China is established for the first time by analyzing 503 PCMSW data sets of 135 prefecture-level cities in China. A hyperspherical transformation method was used to eliminate the constant sum constraint in statistically analyzing PCMSW data. Moreover, a back-propagation (BP) neural network methodology was applied to establish quantitative models between city-level PCMSW and its socio-economic factors, including city size, per capita gross regional product, geographical location, gas coverage rate, and year. Results show that (1) national-level PCMSW in 2017 was estimated as organic fraction (53.7%), ash and stone (8.3%), paper (16.9%), plastic and rubber (13.6%), textile (2.3%), wood (2.2%), metal (0.6%), glass (1.5%), and others (1.0%); (2) organic fraction, paper, and plastics showed an increasing trend from 1990 to 2017, while ash and stone decreased significantly; (3) organic fractions in East, North, and Central-South China were higher than those in other regions. This enables us to fill the data gap in the practice of municipal solid waste management in China.

Demolition waste recycling in China: New evidence from a demolition project for highway development

China's rapid urbanization has led to rising construction and demolition waste (C&DW) amid a quoted recycling rate of only about 10%. Previous studies on C&DW recycling in China have focused on lack of awareness, weak regulation, limited markets for recycled products, and immature recycling technology. This paper investigates the recycling rate of demolition waste (DW) through a case study of the demolition process in a highway project in Taixing, Jiangsu Province, and data collected through analyses of past documents, field observations, and interviews with key stakeholders to provide contrary evidence that the recycling rate is much higher than reported. The reason for the discrepancy is that the reported recycling rate did not include the efforts of a myriad of relocated residents, small construction businesses, informal recycling establishments, developers, and road construction contractors. Proper estimation of the DW recycling rate in China should consider these efforts, especially from the informal sector.

Risk Response for Municipal Solid Waste Crisis Using Ontology-Based Reasoning

Many cities in the world are besieged by municipal solid waste (MSW). MSW not only pollutes the ecological environment but can even induce a series of public safety crises. Risk response for MSW needs novel changes. This paper innovatively adopts the ideas and methods of semantic web ontology to build an ontology-based reasoning system for MSW risk response. Through the integration of crisis information and case resources in the field of MSW, combined with the reasoning ability of Semantic Web Rule Language (SWRL), a system of rule reasoning for risk transformation is constructed. Knowledge extraction and integration of MSW risk response can effectively excavate semantic correlation of crisis information along with key transformation points in the process of crisis evolution through rule reasoning. The results show that rule reasoning of transformation can effectively improve intelligent decision-making regarding MSW risk response.

Effect of source-classified and mixed collection from residential household waste bins on the emission characteristics of volatile organic compounds

The implementation of domestic waste classification following the principles of reduction, recycling, and harmlessness is an effective method to improve the urban and rural environments and to promote resource recycling. However, in many developing countries, the community residents lack awareness of the benefits of classified collection, which leads to a lack of initiative to classify MSW. To make the people realize the importance of MSW classification and increase the classification dynamics, Suzhou, China was taken as an example in this study, and residential areas were selected as sampling sites for classified and mixed collection of domestic waste. The main components of the odorous volatile organic compounds (VOCs) emitted from the dustbins via different disposal modes were determined by sampling in spring, summer, autumn, and winter. In addition, the ozone formation potential (OFP) and human health risk assessment of the VOCs were analyzed. Halogenated compounds were the major pollutants from the household waste dustbins of the residential areas. However, aromatic compounds contributed the most to the OFP of the VOCs. The OFP of VOCs reached the highest peak in summer, which was 1.02 × 10³ μg/m³. Furthermore, more attention needs to be paid in classifying waste to reduce the concentration of OFP. Although there was a carcinogenic risk in spring and summer, it declined after waste classification. Compared with mixed collection, the source-classified collection of garbage had advantages in terms of controlling the emission of VOCs, ozone formation potential, and human health risk. These results could provide the evidence demonstrating the advantages of waste classification and attract people's attention. Furthermore, the results can also provide impetus to those countries, where separate collection of waste has not yet been implemented, to improve the enthusiasm for classification and the integrity of waste classification system. Residents should be encouraged to classify household waste in residential areas.

Vertical distribution of microplastics in bay sediment reflecting effects of sedimentation dynamics and anthropogenic activities

Microplastics are ubiquitous in our environment, yet we have little knowledge on their accumulation profile and changing trend. In this study, we selected the semi-enclosed Jiaozhou Bay as the research area to study the vertical distribution characteristics of microplastic in the sediment and analyzed factors that might affect this distribution pattern. We found six different polymer types and the microplastic abundance ranged between 2.5 items/kg d.w.-27.5 items/kg d.w.. Microplastic abundance was very low in deep sediment and generally showed a decreasing trend from the surface down with some shifts at different depth at certain sites. Based on our data, the total microplastics in the sediment were estimated to reach 3.71 tons in Jiaozhou Bay. This study shows that the vertical microplastic abundance profile in the sediment can not only show the microplastics pollution level but also reflect environmental factors and anthropogenic impacts.

Recent advances in municipal landfill leachate: A review focusing on its characteristics, treatment, and toxicity assessment

Nowadays, sanitary landfilling is the most common approach to eliminate municipal solid waste, but a major drawback is the generation of heavily polluted leachates. These leachates must be appropriately treated before being discharged into the environment. Generally, the leachate characteristics such as COD, BOD/COD ratio, and landfill age are necessary determinants for selection of suitable treatment technologies. Rapid, sensitive and cost-effective bioassays are required to evaluate the toxicity of leachate before and after the treatment. This review summarizes extensive studies on leachate treatment methods and leachate toxicity assessment. It is found that individual biological or physical-chemical treatment is unable to meet strict effluent guidelines, whereas a combination of biological and physical-chemical treatments can achieve satisfactory removal efficiencies of both COD and ammonia nitrogen. In order to assess the toxic effects of leachate on different trophic organisms, we need to develop an appropriate matrix of bioassays based on their sensitivity to various toxicants and a multispecies approach using organisms representing different trophic levels. In this regard, a reduction in toxicity of the treated leachate will contribute to assessing the effectiveness of a specific remediation strategy.

Assessment of Shallow Groundwater Contamination Resulting from a Municipal Solid Waste Landfill—A Case Study in Lianyungang, China

Groundwater contaminations based on the release and transportation of leachate from municipal solid waste (MSW) landfills are a potential hazard to the ecosystem and its inhabitants. In this study, nine chemical compositions of groundwater quality were collected and analysed from 16 monitoring wells and two ponds around the Diaoyushan MSW landfill in the north of Jiangsu Province, China. Multiple analyses were performed to assess the redox conditions and the groundwater environment. It was indicated that the landfill was in a low and stable biodegradability phase, and the most influential phase was the initial stage of the landfill site; the leachate leakage was the principal pollution source (49.18%) for the local groundwater environment. Artificial drainage of Dongdasha village expanded the contaminant plume scopes and deteriorated water quality further. The polluted groundwater area was provided with high concentrations of total hardness, Cl−, SO42−, total dissolved solids (TDS) and Pb.

A factor analysis of residents' performance in municipal solid waste source-separated collection: A case study of pilot cities in China

To explore the potential effectiveness of a localized waste recycling system in Chinese cities, several rounds of a municipal solid waste source-separated collection (MSWSC) program were implemented throughout China from 2000 to 2017. In our study, to evaluate the achievements of the MSWSC program, a structured questionnaire survey and face-to-face interviews were conducted in eight representative cities from the MSWSC pilot cities. Influencing factors were examined via a Hierarchical Linear Model (HLM) on both the individual level and the city level. The differences in MSWSC performance among the eight research cities were investigated through a comparative analysis. The results suggested that gender, age, knowledge of MSWSC, satisfaction with sanitation and satisfaction with publicity had significant impacts on MSWSC, and we further found that the city-level factors influenced the relationship between MSWSC performance and the individual-level variables. Differences among the eight research sites indicated that Nanjing and Hangzhou exhibited relatively high achievements in the implementation of MSWSC program, while Yichun and Guiyang showed poor performance. The experiences of these advanced pilot cities suggest that specific containers for designated waste types, widespread public education, and sufficient MSWSC incentives must be provided and publicized to promote municipal solid waste recycling behaviors. Given the unique status of municipal solid waste management in China and its regional heterogeneity, the MSWSC system should be further discussed with regard to local conditions in a wider range of city settings. Implications: This study attempts to discuss the factors affecting performance on municipal solid waste source-separated collection (MSWSC) by considering the nested data of two levels of individual and city from a structured questionnaire survey. Therefore, a Hierarchical Linear Model is established which can analyze the intra-group and inter-group effects of two-level variables. The proposed method can be expanded to other cities to determine the main factors affecting MSWSC or to evaluate the residents' performance on MSWSC.

Environmental impact of carbon cross-media metabolism in waste management: A case study of municipal solid waste treatment systems in China

Waste treatment is a metabolic process that incurs pollutants migration across environmental media (i.e., air, water, and soil) and involves various conversions of physicochemical forms of carbon. Multiple forms of carbon compounds, such as CO₂, CH₄, CO, VOCs, and other organic matter can contribute to a series of transboundary environmental problems. However, current strategies targeting pollution reduction in single medium may cause pollution transfer to other environmental media, leading to comparatively large difficulty in assessing the related environmental impact on integrated ecosystems. This paper develops an analysis framework of carbon cross-media metabolism in municipal solid waste (MSW) treatment systems that include landfilling, composting, incineration, and anaerobic digestion. Life cycle impact analysis and sensitivity analysis methods are used to recognize the essential technologies in promoting the carbon cross-media migration and decreasing the integrated environmental impacts. The framework is implemented in a case study of the MSW treatment systems of 2013 in China. Results show that 86%-98% of carbon pollutants generated through landfilling, composting, and incineration ended up in the natural environment, while anaerobic digestion achieved an 87% pollution removal rate. Co-generation technology applied in incineration flue gas treatment, biochemical + membrane treatment technology in wastewater treatment, and co-processing of sludge in cement kilns were identified as the essential technologies affecting carbon migration across the gas-liquid, liquid-solid, and solid-gas interface, respectively. The relatively high environmental impacts of landfilling and incineration can be decreased by optimizing their technological compositions and applications. This study can provide support to replace the traditional environmental practice aiming at pollution control in single environmental medium independently by a systematic management approach that considers carbon cross-media metabolism and integrated environmental impact.

Charging for municipal solid waste disposal in Beijing

Considering the various ways of Municipal Solid Waste (MSW) disposal that are currently in practice, this paper proposes a bundle pricing model of MSW disposal in Beijing, China. The bundle pricing model is set according to per capita annual disposable income, per capita annual consumption expenditure and MSW disposal cost based on the cost reimbursement principle and complementarity principle. This paper first estimates the unit costs of landfill and incineration respectively, and then designs three bundling packages according to three different income levels of households in Beijing (low-income households, middle-income households and high-income households). Specifically, based on our bundle pricing model, we propose to charge low-income households (of the average size of 3 persons) MSW fees 5.64 RMB per month, middle-income households 10.16 RMB, and high-income households 20.70 RMB per month. We also discuss and explain how the proposed mechanism can be expected to not only mitigate the capital shortage problem, but also reduce MSW quantity and improve the MSW incineration disposal technology.

Recycling waste thermoplastic for energy efficient construction materials: An experimental investigation

A large stream of research has studied the performance of waste plastics impregnated concrete, reporting multiple benefits and advocating its use in construction works. But no study has reported the merits of bricks impregnated with waste plastics. The present paper reports the results of experiments done on bricks made up of varying percentages of waste thermoplastics (0 - 10% by weight) and sand (60 - 70% by weight), holding percentages of fly ash and ordinary Portland cement constant at 15% (by weight) each. Three types of waste thermoplastics were used, forming three separate batches of bricks. The plastics were polycarbonates, polystyrenes, and mixed plastics. The bricks were cured under water for 28 days. Some of the batches were baked at temperatures ranging from 90 °C to 110 °C for 2 hours in order to melt the plastics to form voids. The bricks made with the above-stated compositions were found to possess low thermal conductivity and adequately high compressive strength. The compressive strength of these bricks is observed to be more than 17 MPa, which lies within the upper half of the range of strengths specified for bricks in the IS 1077:1992 standard. The waste plastics impregnated bricks display high thermal resistance, a feature that can add economic value to the brick manufacturers, motivating them to establish the necessary logistics for collection and use of all types of waste thermoplastics. The paper also presents a regression model to predict the compressive strength of bricks at varying plastic contents. The study, thus, introduces a new strand of research on sustainable recycling of waste thermoplastics in the context of the circular economy.

Review of leaching behavior of municipal solid waste incineration (MSWI) ash

Incineration is widely adopted in modern waste management because it provides an effective way to minimize municipal solid waste that needs to be disposed of in landfills. The ash residue is often disposed by landfilling. Alternatively, the incineration ash may be recycled and reused for various applications. The crucial issues, however, are the leaching of harmful elements during the use and the end-of-life phases. This review summarizes extensive studies on leaching behavior of municipal solid waste incineration ash. Specifically, pollutants generated through leaching, factors governing leaching, methodologies to study leaching, leaching mechanisms, and treatments to reduce leaching. Many types of pollutants are generated through leaching from municipal solid waste incineration ash, in which heavy metals and organic contaminants are the most toxic and concerned. Ash properties, pH and liquid to solid ratio are the main factors governing municipal solid waste incineration ash leaching. Leaching behavior of municipal solid waste incineration ash is complicated and existing methods to evaluate leaching may not be able to represent the field conditions. Solubility and sorption are the two major leaching mechanisms. Many treatment methods have been proposed. However, not all methods are effective and some approaches are associated with high energy and high cost, which makes them less economically feasible and attractive.

The policy-making trend analysis of municipal solid waste in China 1980-2015

Over the past 35 years, the Chinese government has established various policies to tackle problems related to the municipal handling of solid waste. It is necessary to study policy-making trends in the area of municipal solid waste for further sustainable development in China. This article fills this gap by designing a new analytical framework made up of policymaker indicators, policy practitioner indicators, policy beneficiaries' indicators, policy tool indicators, and policy support indicators in order to analyse the policy-making trend based on China's major municipal solid waste policies from 1 January 1980 to 1 March 2015. Results have shown that policy-making related to municipal solid waste has changed significantly in the past 35 years and that more municipal solid waste policies were issued by one or a few ministerial departments than by the State Council and National People's Congress. Moreover, the study has shown that the government and companies have dedicated more attention to taking action about municipal solid waste than individuals. With regard to the policy tools, policy-making has stressed the use of market-type tools, regulation-type tools, and public participation-type tools together to tackle the municipal solid waste problem since 2000. Finance and information support were used more as policy support by municipal solid waste policies than technology. This article provides some novel insights on the policy-making trend of municipal solid waste in China.

The Evaluation of the Heavy Metal Leaching Behavior of MSWI-FA Added Alkali-Activated Materials Bricks by Using Different Leaching Test Methods

Alkali-activated materials (AAMs) not only have the potential to replace cement applications in architecture and civil engineering, but also have an excellent effect on the stabilization solidification of hazardous industrial wastes. This study used two types of municipal solid waste incineration fly ash (MSWI-FA)-grate firing fly ash (GFFA) and fluidized bed fly ash (FBFA)-as AAMs brick raw materials. It is discovered from this study that AAMs bricks with different weight ratios of GFFA and FBFA can both meet the required standard of GB21144-2007 (Solid concrete brick). From the results obtained from the four leaching tests, the equilibrium pH of the leachate varies, resulting in significant differences in the leaching of heavy metals in Raw GFFA, Raw FBFA, and AAMs bricks with GFFA and FBFA. The AAMs brick with the addition of GFFA and FBFA has an alkali activation system to encapsulate heavy metals. By comparing the results obtained from the CEN/TS 14429 leaching behavior test and the four batch leaching tests, it was found that the most influential factors for the heavy metal leaching concentration are whether the heavy metal has been solidified/stabilized in the samples. GFFA and FBFA tend to have consistent characteristics after being activated by alkali to form AAMs bricks. This can be confirmed by the acid neutralization ability concentrated on a specific pH range. The results obtained from CEN/TS14429 verified that the AAMs bricks with the addition of GFFA and FBFA have excellent environmental compatibility and that it provides a comprehensive evaluation on the environmental compatibility of the test materials and products. This demonstrated that the MSWI-FA is suitable for used as alkali-activated materials and its products have the potential to be commercially used in the future.

Economic development and environmental sustainability-the case of foreign direct investment effect on environmental pollution in China

This research reviews and analyses the environmental catastrophes in China with regard to its adherence of global environmental policies and practices. The research makes available evidence of the present policy regime and institutions, strategies for curbing emission, environmental legislations and regulations and measures to provide a sustainable environment for the present and future generations. This paper reviewed how the environment is affected by the emissions. The findings revealed that China adheres to global policies and practices. China also receives local and international support in terms of assistance in dealing with environmental challenges. It was also revealed that carbon dioxide was not included in the list of pollutants to be taxed by the environmental protection tax law. Furthermore, the government needs to be strict at the local and district levels in enforcing the law to ensure professionalism and attainment of set standards.

Improved impact assessment of odorous compounds from landfills using Monte Carlo simulation

Landfills are city infrastructures used for the treatment of municipal solid waste (MSW) in China. However, due to technical failure and/or management problem most of them are facing serious secondary pollution such as groundwater contamination and odor nuisance. The latter is the main reason causing a growing number of public complaints. Atmospheric dispersion models are routinely adopted for odor impact assessment, but these models provide deterministic predictions only. To determine the potential odorant paths and treat the uncertainty of odor pollution, Monte Carlo simulation coupled with an odor dispersion model was proposed and named Monte Carlo-dispersion simulation method (MCDSM). By introducing a series of random values of error components in the dispersion model, MCDSM can produce probabilistic odor impact results. Values of these variances were randomly selected according to their probability density functions (PDFs) due to the imprecise knowledge of the meteorological and emission conditions. After running the odor dispersion model for numerous times, the randomization produces a set of possible results that closely resembles the expected behavior of the odorants. This study applied MCDSM to estimate the odor impact of methyl mercaptan (CH₃SH) on an MSW landfill in Beijing, China. The PDF of the CH₃SH emission rate was derived from the field data. The uncertainty of odor impact was analyzed statistically, and the results were summarized using the probability of odor exceedance (POE). A POE map of CH₃SH was plotted for a particular interest, in which the north downwind direction was the most polluted area. MCDSM provides a scientific approach for the assessment of odor pollution from individual odorant, which can benefit the formulation of standard for odor impact assessment in landfill sites.

Factors Associated with Composting of Solid Waste at Household Level in Masaka Municipality, Central Uganda

The domestic solid waste stream composition of urban settings in many developing countries including Uganda is largely biodegradable in nature, and thus, composting provides the most suitable solid waste management option for these wastes. However, there is limited information about waste composting at the household level and associated determinants in Uganda. A cross-sectional study was employed to collect quantitative data from 368 residents of Masaka municipality, Central Uganda. A semistructured interviewer administered questionnaire was used which assessed knowledge, perceptions, and practices of composting. Data were analysed using STATA 13.0, and binary logistic regression was used to determine the factors that influence composting at the household level. Of the 368 participants, 11.4% were engaged in composting. Factors associated with household level composting were age of 46 years and above (aOR = 2.69, 95% CI = (1.06–6.80)), possession of a garden (aOR = 28.88, 95% CI = (3.85–216.72)), engagement in waste segregation (aOR = 5.56, 95% CI = (2.25–13.86)), and periurban residence (aOR = 3.81, 95% CI = (1.78–8.16)). The practice of composting at the household level was low. This therefore highlights the need for urban authorities to develop initiatives for promoting composting at the household level while considering the identified predictors associated with composting.

Evaluating the Efficiency of Municipal Solid Waste Management in China

Poor public health is always associated with the mismanagement of municipal solid waste (MSW). Many cities are besieged by MSW in the world. It is essential to do a good job in MSW management (MSWM). In order to improve the efficiency of MSWM, the Chinese government has intensively implemented relevant policies. There are still few studies on MSWM efficiency in China. The research aims to comprehensively analyze MSWM efficiency, find high-efficiency MSWM policy implementation routes and the breakthrough on improving MSWM efficiency. To measure Chinese MSWM efficiency accurately, this paper introduced the three-stage data envelopment analysis (DEA) model into the research. According to the results of DEA, Fuzzy c-Means algorithm was used to the cluster analysis of 33 typical cities. After eliminating the interference of the external environment and random disturbance, the mean value of MSWM efficiency declined from 0.575 to 0.544. The mean of pure technical efficiency (PTE) was declined from 0.966 to 0.611, while the mean of scale efficiency (SE) increased from 0.600 to 0.907. The PTE of central and northeastern cities was relatively low. The SE of western cities was comparatively high and the efficiency distribution of the eastern region was relatively scattered. In general, MSWM efficiency is low and expected to be improved. Regional differences in MSWM efficiency have been shown. The management effectiveness of eight pilot cities (MSW classification) is affirmative but not that significant. To improve MSWM efficiency, differential management for four types of cities should be carried out.

A Study of the Relationships between the Characteristics of the Village Population Structure and Rural Residential Solid Waste Collection Services: Evidence from China

Based on survey data collected in 2016 from 100 villages across five provinces in China, this paper uses binary logistic model to explore the main factors related to the supply and quality of rural residential solid waste collection (RRSWC) services, especially focusing on the role of village population structure characteristics. It is indicated from the results that village population structure characteristics are significantly correlated with RRSWC services; specifically: (1) the total registered population of village households is significantly positively correlated with the supply of RRSWC services, however, the correlation between the registered population and the quality of RRSWC services is negative and the more the labors working and living outside the village, the less likely the village is to provide RRSWC services; (2) the villagers' educational levels and RRSWC services show no significant correlativity at the present stage; (3) the preferential policies brought by population structure advantage play a positive role in the supply of RRSWC services but is not clearly related to the quality of RRSWC services, especially in the villages with a larger minority population. In addition, the study finds that, the economic development level of a village and the characteristics of village leaders are also positively correlated with the supply and quality of RRSWC services and; the natural and traffic conditions have no significant correlation with RRSWC services. This study can act as a reference for the further promotion of the development of RRSWC services in China.

The steam gasification reactivity and kinetics of municipal solid waste chars derived from rapid pyrolysis

Municipal solid waste treatment has been and will continue to be a major issue facing countries worldwide, and gasification has recently gained more attention as an efficient and clean technology. The steam gasification characteristics and kinetics of five different municipal solid waste chars had been investigated by the method of isothermal thermogravimetric analysis. The results showed that the gasification reactivity increased with gasification temperature. Effect of H/C and O/C ratios, ash composition and particle pore structure of chars on gasification reactivity were studied, which illustrated that the H/C and O/C ratios and ash composition had great influence on gasification reactivity and the pore structure cannot explain well in this study. A homogeneous model, unreacted shrinking core model and random pore model were employed to describe the kinetic behavior of different chars, and the kinetic parameters were also obtained. Finally, through the evaluation of the three kinetic models by comparing the experimental data with the fitted results, the random pore model was determined to perform best. This study should, therefore, be of some value to solid waste gasification industrialization.

Is the finer the better for municipal solid waste (MSW) classification in view of recyclable constituents? A comprehensive social, economic and environmental analysis

With the accelerating pace of urbanization, the continuous increase of municipal solid waste (MSW) has become a major obstacle to China's economic development. Therefore, China recently regards MSW classification scenario as an important strategy for national ecological civilization. However, published references have not focused on MSW classification in view of environmental, economic and social acceptation simultaneously. This research proposes a new Decision Support System (DSS) model considering all three aspects to analyze the comprehensive benefit of the four MSW classification scenarios in Pudong (Shanghai, China) using cost benefit analysis (CBA), life cycle assessment (LCA) and analytical hierarchy process (AHP). Among them, there is an important boundary factor in the life cycle assessment. This work mainly focuses on the net energy consumption, namely the air and water emission of different substances. The results show that the classification scenario II, dividing MSW into toxic and hazardous waste, recyclable, kitchen waste and combustible waste, is the best option. Although scenario III (MSW is divided into toxic and hazardous waste, recyclable waste (paper, plastic, scrap metal, waste glass and other small class), kitchen waste and combustible wastes) and IV (recyclable waste in Scenario II is further classified, for example, paper is subdivided into newspapers, books, cardboard, etc.) further refine the MSW classification, the DSS model analysis results indicate that neither of these are the most feasible scenario. Therefore, finer classification is not always the better if we consider all three pillars of sustainability.