Microplastics pollution is one of the most pressing environmental problems of the 21st century. While microplastics are pervasive throughout various environmental compartments, research to date has primarily focused on marine systems. Land-based microplastics sources (e.g., solid waste) have received comparatively little attention, although they account for the main flow of microplastics into aquatic environments. Solid waste microplastics sources primarily include landfill refuse, sludge, and food waste. Microplastics in these waste streams can be associated with various micropollutants that can have deleterious impacts on ecosystem health as they enter the food chain. Thus, understanding the occurrence, fate, and degradation pathways of solid waste microplastics is essential to develop comprehensive control and mitigation strategies. This study critically reviewed these key aspects of microplastics in municipal solid waste landfill refuse, sewage sludge, and food waste, and identified the interconnections of these components in the proliferation of microplastics to the environment. Additionally, microplastics related laws and regulations and their relevance to solid waste microplastics mitigation are discussed.
Globally increasing concern related to municipal solid waste generation is encouraging research efforts on developing alternative routes to valorize mixed refused wastes. In this way, catalytic pyrolysis is emerging as an interesting and efficient technology due to its great flexibility in terms of feedstock. In the current work, upgrading of a Solid Recovered Fuel (SRF) has been investigated by catalytic pyrolysis over nanocrystalline ZSM-5 zeolite (n-ZSM-5), paying special attention to dechlorination effects due to the high Cl content of the raw waste. Thus, pretreatment of the SRF by water washing and mild thermal pre-treatment allows for a significant reduction of the Cl concentration. Regarding the catalytic pyrolysis step, the best conditions correspond with a temperature of 400 °C in the catalyst bed and 0.50 catalyst/SRF mass ratio, which lead to ca. 30 wt% oil yield (rich in aromatic hydrocarbons) together with 40 wt% gas yield (rich in C3-C4 olefins). Accordingly, these products could find use as raw chemicals or for the production of advanced fuels. In addition, zeolite reutilization has been tested for several cycles, denoting a progressive modification of the products distribution because of coke deposition. However, an almost total recovery of the n-ZSM-5 zeolite catalytic performance is achieved after regeneration by air calcination, affording the production of an oil fraction with a Cl content as low as 40 ppm.
Introduction: Municipal garbage/refuse, sludge, industrial and commercial waste, etc. is termed Solid Waste (SW) and those who handle such waste are SW workers. But the COVID-19 pandemic has hit them hard. SW workers play a vital role in waste management to safeguard and promote public health. But they are often unappreciated and the various health risks and vulnerabilities associated with waste handling are overlooked. This study aimed to review the working conditions and morbidities of SW workers highlighting the longstanding challenges before and after the onset of COVID-19 in India. Methods: Databases such as PubMed and Google Scholar were used for the inclusion of articles. Drawing from the literature on the working conditions and morbidities of SW workers in India alongside grey literature and news reports by electronic media during the pandemic, this paper highlights the longstanding challenges of SW workers. Results: The health morbidities and structural challenges due to caste, and class that were reported as being faced by SW workers across the studies have worsened at the onset of COVID-19. There is a multiplying effect of their vulnerability due to the disadvantages of caste and class. Due to power dynamics, they were forced to work without proper wages and appropriate healthcare resources. Many incidents across the country reported stigma and discrimination; poor access and utilization of Personal Protective Equipment (PPE) among SW workers resulted in infections and deaths due to the pandemic. Lack of proper data on COVID-19 infected SW workers; lack of proper certification had halted their insurance claims. Conclusion: This paper noted the multiplying effect of long-standing vulnerabilities that were exposed during the pandemic. Proper maintenance of health records and a sustainable employee grievance redressal mechanism are essential. The need of the hour is to focus on strategies to improve their working conditions along with policies to protect their dignity and empower them.
Khadija Sarquah, Satyanarayana Narra, Gesa Beck
et al.
Among the sustainable ways of municipal solid waste management (MSW) is energy recovery, particularly into refuse derived fuel (RDF). However, the potential, application, and research of RDF in existing cases is not exhausted. Additional analysis of literature is needed to provide further insights into the area. The evolution of RDF research over the past 30 years is analyzed and presented in this paper. Using a statistical approach, a bibliometric analysis was conducted for research on RDF from the SCOPUS database to assess perspectives and trends and gain a better understanding of the scope of RDF research. The bibliometric analysis tools, co-citation, keyword occurrence, co-authorship, and bibliometric coupling network, were utilized in VOSviewer to map out keywords, collaborations, and citations. The result from the analysis indicated that scholarly works around RDF were largely written in English (92.7%). Journal articles were the most frequently occurring document type, representing 68.5% of the records, followed by conference papers (24.9%). Out of a total of 1184 documents analyzed, the number of publications rose steadily from 26 in 2003 to 102 in 2021. Most publications on RDF were in the subject area of Environmental Science (648), Energy (483), and Engineering (441). Waste Management, Fuel, Waste Research and Management, and the Journal of Cleaner Productions were the sources that contained most of the publications on RDF research. The contributions (number of publications) in the RDF research were largely from the US (176), Italy (97), Japan (90), Germany (86), China (79), and the UK (74), among others. Collaborations were notable between the US, Europe, and the Asian regions (China, India, and Thailand). Conspicuously missing were research contributions from the African region, comparatively, thus emphasizing the need for contributions from such perspectives. The keyword analysis result further showed studies were within knowledge areas of conversion processes, applications, and management. Thermochemical conversion pathways were highly applied to RDF and thus combustion/co-combustion/incineration (717), gasification (224), and pyrolysis (115). Additionally, research on RDF applications was mostly in the cement industry (150) and electricity generation (55). The time incident analysis outlined recent interest and emerging trends in optimization of valorization processes, towards a circular economy and sustainability. Cross-cutting areas of environmental focus (emissions) were observed along the years analyzed. There is a rising focus on indicators for commercialization, environmental impacts, and optimum production from the analysis. This is useful especially for the emerging regions/territory of research contributions. These discussions would potentially maximize the co-benefits of energy generation and eco-environment sustainability via cost benefits deployments suggested for future research. Analyzing the RDF research trends, these findings are useful for the future endeavor of researchers and developers.
Municipal Solid Waste (MSW) becomes a point of focus globally due to its harmful effects on the environment and human health if it is not managed properly. MSW was proved globally to be used as a resource, and it has a major opportunity in the realm of conversion technologies. Accordingly, this study aims to explore the enablers and barriers to six different MSW management (MSWM) technologies adopted in the Kingdom of Bahrain, in order to ensure the successful adoption of these technologies that are Anaerobic Digestion (AD), Incineration, Pyrolysis, Gasification, Composting and Refused Derived Fuel (RDF). This study provides sufficient information to the decision and policy-makers for the processes of selection and adoption of the MSWM technologies in Bahrain, using a qualitative approach “mainly semi-structured interviews” with experts and then Thematic Analysis using nvivo12 software. The results show that the main themes that enablers and barriers fall under are: political (e.g. national waste management strategy), technical (e.g. segregation at source), managerial (e.g. capacity building), social (e.g. public awareness), economic (e.g. incentives to investment) and environmental (e.g. air quality). This study concluded that in order to succeed in the MSWM technologies adoption, the resulted barriers should be overcome. Furthermore, Incineration was recommended as the best solution to manage MSW which has the least barriers and most enablers in Bahrain as per the experts.
Andrea Kałuża-Haładyn, Elżbieta Jamroz, Jakub Bekier
Abstract The aim of the study was to assess the transformation of humic substances during composting of biomass of energetic plants and municipal solid waste. The type of the organic material to be composted and the type of technology used affect the course of the humic substances transformation and formation of compost maturity parameters. Compost produced from the mixture of energetic willow and hay biomass contained humic substances with higher share of low-molecular fractions and lower share of humic acids in total organic carbon than those produced from municipal solid wastes. Obtained results also showed that insoluble alkali fraction plays an important role in humification process by its convertion to a new humic substances. Share of humic and fulvic fractions in relation to the total organic carbon appears to be reliable indicator of composting as a process of enhancing organic matter humification.
The objective of this study was to optimize the parameters for the development of refused derived fuel (RDF) pellets from municipal solid waste (MSW) and rice husk by using Response Surface Methodology (RSM). In this a systematic study was conducted, where three parameters were varied according to RSM factorial design. The binder concentration (5-10%) pressure (700-1200 psi) and retention time (3-7 minutes) were used for RDF pellet development under hydraulic press, measured hardness bulk density (BD) and durability (DU). The T3 treatment results revealed the highest pellet hardness, bulk density, and durability 25 kg, 805 kg/m3, 99% respectively by application binder concentration (5%), pressure (1200 psi) and retention time (5 minutes). The experimental data on response variables were fitted into quadratic polynomial model using the multiple regression analysis and found that it was statistically significant quadratic model. The RDF physical chemical and mechanical characteristics were also evaluated and found their relationship between HHV, carbon, ash, DU, BD and energy density. The ash contents were inversely proportional to DU and HHV whereas DU was directly related to BD. Bangladesh J. Sci. Ind. Res.54(4), 329-338, 2019
BackgroundRefuse collectors are at a high risk for fatal and non-fatal occupational accidents. This is more intensified in developing countries, like Ethiopia, due to physically demanding nature of the job. However, information on occupational injuries and related factors are almost non-existent in Ethiopia. Thus, the aim of this study was to assess the prevalence of occupational injuries and its associated factors.MethodsA cross-sectional study was conducted among municipal solid waste collectors in four zones of Amhara region from February to May 2015. Computer generated simple random sampling technique was used to select the samples. Interviewer administrated questionnaires were used for the data collection process. Binary logistic regression was used to assess the association between outcome variables and explanatory variables.ResultsIn this study, the annual prevalence of at least one occupational injury among solid waste workers was 34.3 % (95 % CI: 29.52, 39.10). Of these, 50.7 % of them were visited health facility to receive health care. The independent predictors of at least one occupational injury were shorter service years, low monthly salary, history of job related stress, and sleeping disturbance related to the job. Being illiterate, having lower monthly income, and those who reported sleeping disturbance were significantly and positively associated with severe occupational injuries of solid waste collectors.ConclusionThe magnitude of occupational injuries among municipal solid waste collectors is lower than other similar studies conducted in Ethiopia. Based on the finding of this and other studies, job rotation among work components, improvement of employees’ income, job specific guideline regarding maximum production limits, and replacement of bags and bins with wheeled containers are an interventions expected to cope with the problem. There is also a need of specific periodic health surveillance (PHS) for refuse collectors to detect early signs of work related complaints and to monitor work ability.