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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. [ABSTRACT FROM AUTHOR]

The purpose of this research is to demonstrate the utilization of animal wastes and by‐products in the production of low‐energy and low‐CO2 clinkers and cements in order to preserve natural resources, such as limestone, while reducing CO2 emissions released from the cement manufacturing process and reducing potential health risk to the world population (such as bovine spongiform encephalopathy or other health issues...). Pure calcium sulfoaluminate clinker was produced with calcium hydroxide, aluminum hydroxide, and calcium sulfate hemihydrate; followed by additional clinkers produced from substituting calcium hydroxide with bone ash (from 0 to 100% of the calcium hydroxide replaced). The final clinkers contained various amounts of ye'elimite, calcium aluminate phases, as well as tricalcium phosphate, depending on the firing temperature. Finally, some preliminary results on the hydration process and compressive strength are provided for the production of these binders. [ABSTRACT FROM AUTHOR]

Recently, in geotechnical engineering, waste utilization and management have become immensely important in terms of reducing the ratios of environmentally harmful and relatively expensive chemical soil strengthening additives. Glass manufacturing waste (GMW), among the above-stated waste materials, comes to existence as the mineralogical part required to produce glass is separated from the mined material. GMW leads to serious environmental pollution incessantly. This study aims to investigate the effects of GMW to the bearing capacity and time-dependent consolidation settlements of clayey soils (CS) in an environmentally friendly approach. In this regard, GMW, which has not yet been considered in the relevant literature, was activated with KOH, NaOH and CaO alkali activators to form geopolymer mortars. Large-scale model experiments were performed on geopolymer-CS mixtures and up to 7.35 times bearing capacity increments along with 6.90 times settlement reductions were reached compared to unimproved CS. Optimum GMW ratio was found as 25% and CaO was determined to be the most ideal alkali activator. Curing temperature and durations were examined and it was deduced that both affected the results significantly. Results were compared to those of cement and remarkably close bearing capacity and settlement improvements were achieved in an environmentally friendly approach. [ABSTRACT FROM AUTHOR]

The article is devoted to the question of justifying the feasibility of acquiring competences in the field of waste management at the national, industrial, regional and individual levels. The purpose of the article is to characterize the state of waste management in Ukraine in the pre-war period, to summarize the experience of waste management in European countries, and to highlight the peculiarities of the formation of waste management skills in Ukraine in the post-war recovery period. Considering the dynamic of capital investments on environmental protection in Ukraine, it’s sustained the necessity of addition measurements in the area of waste management in order to increase the results of this activity, namely by determining the basic skills waste management. The article examines the share of utilized waste in the total amount of waste generated by the regions of Ukraine. The analysis is complemented by an analysis of the dynamics of industrial production and it is concluded that in the conditions of a low share of waste utilization and the growth of the index of industrial production, it is necessary to develop waste management skills in industry. A study of the public's perception of the situation with waste management was conducted. Based on the generalization of domestic and foreign experience in waste management, the skills that are necessary for realization of all levels of the waste management hierarchy were considered, namely: skills for prevention of waste generation and its reduction, preparation for waste reuse, waste recycling and another types of waste disposal were highlighted. [ABSTRACT FROM AUTHOR]

Using biomass waste as supplementary cementing material (SCM) in concrete has attracted researchers' attention for efficient waste utilization and reducing cement demand. Sugarcane bagasse ash (SCBA) is one such example of biomass waste. It is an agricultural waste obtained when sugarcane bagasse from the sugar industry is used for power generation and disposed of in open-air dumping sites. Its waste disposal causes the generation of particulate matter, degrading air quality. In this study, the effect of processed SCBA as SCM in concrete has been investigated. The processing of the SCBA involved the removal of fibrous and carbon-containing particles by sieving followed by grinding. The SCBA was ground for 45 min until the surface area was comparable to that of cement and was then used for further characterization and incorporation into concrete. The 45 min grinding time resulted in 2.92 times higher pozzolanic reactivity of the SCBA. The SCBA was incorporated by replacing cement in different weight fractions (10%, 20%, 30%, 40%) in concrete. Test results showed that the concrete workability increased with SCBA incorporation, whereas the resulting concrete density was reduced. The results of the mechanical properties, including compressive sstrength and hardened density, were enhanced upon the cement replacement by SCBA. Concrete containing 30% SCBA can be used for structural applications as its 28 days compressive strength was 21 MPa, which complies with ACI 318-16 specifications. Concrete resistance against scaling and leaching due to adverse effects of sulfuric and hydrochloric acid considerably increased with SCBA addition and was due to microstructure densification by secondary hydrates formation as lower portlandite content was detected by thermogravimetric analysis. Hence, SCBA processing increases its reactivity, as reflected by the improved mechanical properties and greater durability of SCBA-incorporated concrete. [ABSTRACT FROM AUTHOR]

Effective disposal of organic wastes has been one of the most important issues for the resource utilization of solid wastes. The degradation rate of organic components as a key factor can pose a serious impact on the composting process. In this study, a series of experiments were performed on the microbial agents and various ventilation systems, in order to evaluate the co-composting performance of kitchens, green wastes, and exhausted tea on a pilot scale. An optimal compound ratio was also achieved to verify the strengthening effect of co-composting. The specific organic components included the fat crude, fibers, and protein in the mixed ingredients during composting. Specifically, kitchen waste, green waste, and exhausted tea were selected as the main raw materials. An aerobic composting was then carried out to control the ventilation and the type of microbial agents in a pilot composting plant. Some parameters were selected to fully evaluate the technical feasibility and economic viability of the co-composting system, including the temperature, water content, the carbon to nitrogen ratio, total nutrients, organic matter content, seed germination index, and hygienic characteristics. The results showed that the optimal combination was the self-developed microbial agents under the intermittent ventilation pattern, where the ratio of compound agents for the co-composting was that m(Aspergillus oryzae): m(Bacillus licheniformis): m(Candida lipolytica): m(Trichoderma viride): m(Azotobacter chroococcum) = 1.5:1:1.2:2:1. Meanwhile, the microbial agents presented a stronger removal effect of the specific organic component in the mixed ingredients, when the inoculation amount was 1‰. Three classic phases were obtained in the temperature of the mixed ingredients during 10 days of drum composting, including heating, thermophilic, and cooling phases. Furthermore, the maximum temperature was up to 68.6℃, while the high-temperature period (65℃ or higher) remained for 7 days. The ratio of water content and carbon to nitrogen declined from 63.5% to 30.1%, and 31.5 to 9.6, respectively, during the entire composting. The total nutrient (9.8%) and organic content (43%) were superior to the Agricultural Industry Standard NY 525-2021. Meanwhile, the seed germination index of the composting product reached up to 88.3%, indicating the perfect hygienic characteristics of composting (3 or fewer fecal coliforms per grams, no ova of roundworm was found). For economic feasibility, the co-composting system was applied for the domestic waste treatment in a district with a population of 30 000 in the Hengqin area of Zhuhai, Guangdong Province, China. A systematic analysis was made to consider the revenues (including waste disposal, organic fertilizer products, and scrap recycling revenue) and expenses (including utilities, salary, transportation, landfill disposal, venue rental, machinery and equipment depreciation, and unforeseeable expenses) during practical application. The average disposal cost was required as low as (248.67±19.89) yuan/t. As such, a process control strategy can be recommended to recycle the kitchen wastes, green wastes, and exhausted tea in the ecosystem, instead of being discarded as solid wastes. The short processing time can be widely expected to accelerate the degradation rate of organic matters for better compost quality during resource utilization. Meanwhile, an improved process control system can be used for the organic waste composting in a rotary drum reactor. The finding can provide a strong reference to effectively treat the environmental pollution of organic wastes in the large-scale kitchen waste, green waste, and exhausted tea at low cost. The recycling of organic waste resources can greatly contribute to reducing landfill disposal for less environmental pollution. [ABSTRACT FROM AUTHOR]

Injection of fluid into subsurface geologic strata for geothermal energy, oil production, and waste disposal has been linked to induced seismic activity in the United States as well as in several other countries. According to the report of the National Research Council of United States of America thousands of induced earthquakes were reported at the numerous sites, where oil and gas recovery and waste disposal activities took place. Most of these induced earthquakes were small magnitude events (Moment Magnitude [Mw] < 4), although earthquakes of magnitude (Mw) 6.5 to 7 were also reported near the oil and gas production sites. This paper presents the results of a review of case histories on increased seismic events due to deep well injection (DWI) and oil extraction. Key factors that may lead or contribute to increased seismicity will also be discussed. [ABSTRACT FROM AUTHOR]

Among other African cities, in terms of solid waste management (SWM), Harare has been ranked as one of the poorest. The municipality struggles to efficiently provide SWM services to its residents. Considering that SWM systems are complex, the individual behaviour of its components (waste generation, collection, and disposal) determines the overall performance of the system. This mini-review thus aims to understand the management system of the urban city's biggest source of solid waste which is household solid waste (HSW). The systematic literature review methodology using NVIVO was used to analyse the literature. Out of a selected sample size of 500 journal articles, 26 were selected based on their relevance to the study. The uncertainty of the data provided by the Harare City Council (HCC) and of HSW generation data harvested in the literature was calculated. According to the HCC data records, Harare has an average daily waste generation per capita of on average 0.38±0.1 kg producing about 207, 635, 294±56, 027, 040 kg of HSW generated annually. With the waste collection efficiency in Harare at about 72.4%±7.5%, the city collects approximately 170, 385, 600±33 384 209 kg of HSW annually. All the collected HSW is disposed of in the city's major MSW dumpsite called Pomona and only about 23, 498, 400±3, 988, 817 kg MSW is recovered annually with the average recovery efficiency at around 9.5%±2.8%, where most of the waste recovery is done by the waste pickers. [ABSTRACT FROM AUTHOR]

With reference to the case of (West) Germany and three different historical episodes, this article asks to what extent the metaphor of the cycle and of closing material loops served actors to demand or achieve more waste recycling. It considers waste (first) in the city around 1900, (second) in the Nazi regime and (third) the post-war West German waste disposal system. Similar to today’s call for a »circular economy«, the circular metaphor suggested that material »cycles« could be technically closed. Nature and its biogeochemical cycles proved the model for this circular thinking among hygienists, waste experts, urban engineers and many others. The circular metaphor expressed the hope that the problem of waste could be solved technologically without having to profoundly transform the social metabolism of society and its structures of production and consumption. To this day, even scientific, technological and economic knowledge about entropy or the complexity of recycling’s logistics and material transformations has not diminished the persuasiveness of the closed loop metaphor. [ABSTRACT FROM AUTHOR]

[Display omitted] • Characterization of MIBA from 3 MSWI plants in Delhi to assess disposal or reuse. • Compilation of 50 studies on MIBA leaching to identify CoCs critical to fate of MIBA. • Comparative assessment of CoCs to evaluate variability across countries. • Emphasis on mandatory inclusion of the identified CoCs in future studies. Present study characterizes municipal solid waste incineration bottom ash (MIBA) from three incineration plants in Delhi with an intent to serve the dual objectives: a) assessing the disposal/reuse options for Delhi MIBA, b) evaluating variability in results across the countries (including India) and assessing if is significant enough to influence the fate of MIBA of varied origin. A review on leaching studies of MIBA (50 research papers) was conducted which aided in achieving both the objectives. Delhi MIBA samples were analysed for chemical composition. The two commonly adopted leaching tests i.e., TCLP and EN 12457–2, were conducted and the results were checked against regulatory threshold levels (RTLs) to achieve the first objective. Leaching concentration of the contaminants was compared with the compiled literature and RTLs to accomplish the second objective. The compendium of literature most importantly revealed the physicochemical parameters which are pivotal in determining the fate of MIBA but have been missing from many studies. Ten such parameters were identified: Cr, Cu, Mo, Sb, Cl - , SO 4 2- , Cd, Pb, Ni and Zn and are referred as contaminants of concern (CoCs). Delhi MIBA was found suitable for disposal to non-hazardous waste landfills and unsuitable for unrestricted reuse. CoCs identified in Delhi MIBA were identical to those observed in literature (except Cd, Pb and Zn). The variability in leaching concentration of CoCs, observed from comparative assessment of results, spanned nearly 2 to 3 log 10 magnitudes for Cu, Cr, Pb, Sb and Zn while 1 to 2 log 10 magnitudes for Mo, Cl - and SO 4 2-. [ABSTRACT FROM AUTHOR]

Co-production is a paradigm shift from the traditional model of public policymaking and service delivery that advocates for the involvement and participation of end-users of services as co-partaker in the process. In this paper, we examined the emerging models of co-production in solid waste management in Nigeria using a case study methodology. Four cases were purposefully selected for detailed exploration. The results of the analysis show that the involvement of the plurality of the non-state actors in waste management co-production brought in innovation through ICT, financial resources through grants, and increased public awareness. And have also given the service receivers a change of orientation that makes them perceive waste as a source of income rather than all rubbish needed to be discarded. However, possible exploitation of informal waste pickers, unclear business models, and absence of prior arrangement for coming together of both state and non-state actors in designing the service production are challenges to the emerging co-production cases. The current study further shows that the emerging co-production efforts have huge potential in promoting circular economy as it creates a better avenue for the implementation of extended producer responsibility (EPR), the establishment of eco-industrial parks, and safe integration of informal waste recyclers. [ABSTRACT FROM AUTHOR]

Fusion has the prospect of producing only low-level radioactive waste, but the volume of this waste is potentially very large. A possible means of reducing the volume of this waste is to recycle the activated materials, e.g. within the fusion industry. In the process of steelmaking, certain impurities are removed via accumulation in slag or fumes produced during the process, and this has been successfully employed as a means of clearing surface-contaminated LWR steels (e.g. steam generators). In this work, we simulate the process applied to neutron-activated fusion reactor components including the blanket, divertors, and shielding. The process is based on a well known partitioning between melt, slag, dust, and gas that is based on the oxidation potential of the elements and their volatility. We model this partitioning of activated materials and use FISPACT-II to simulate their activation during operation; the processes are repeated cyclically to simulate the long-term accumulation of activation products in the steel and waste products. The principal findings are that most of the induced activity remains in the metal rather than accumulating in the slag, and that while the slag remains a low-level waste under the assumptions employed, its volume actually exceeds that of the recycled material, and it therefore did not constitute a successful waste volume reduction technique. [ABSTRACT FROM AUTHOR]

• The sidewall and tread of spent tires were separated to produce pyrolysis chars. • The influence of pyrolysis temperature on spent tire char properties was compared. • Sidewall char seems to be a high-quality fuel according to the better combustion properties. • This research provides new ideas for spent tires disposal and resource recovery. Waste tires are one of the most abundant waste streams. Recycling processes that adapt to the complexity of waste tires, such as pyrolysis, need to be improved. In this study, the tread (TT) and sidewall (SW) of the tires were pyrolyzed separately and the resulting chars were systematically investigated for their physicochemical and combustion properties. The results showed that the fixed carbon content of the SW was higher than that of the TT, and that there was an enrichment of harmful elements (Zn) during the pyrolysis process. The main temperature range for pyrolysis was 350–500 °C. Only natural rubber was present in TT, while synthetic rubber was also present in SW. The char produced by TT consisted of a large amount of amorphous carbon with a higher specific surface area and more developed pores. A large number of Si-O bonds were present on the surface of TT, while more Zn-S bonds were present in SW. The char produced by TT was less graphitized and the spacing between the aromatic lamellae was greater. The functional groups of TT and SW pyrolysis char are relatively single, mainly C-H/C-O. The volatile content of SW pyrolysis carbon is only 3.72%, and the ignition temperature and activation energy are lower than those of TT pyrolysis carbon, which can reduce the consumption of fossil fuels as a higher quality fuel. The ash of TT and SW pyrolysis chars can be used as Si and Zn raw materials respectively, thus realizing a deeper resource utilization. [ABSTRACT FROM AUTHOR]

Highly crosslinked thermoset plastic waste is generally regarded as unrecycled materials and dumped into landfills. To divert the waste from landfills, recycling thermoset waste as fine particles in cementitious composites is a potential approach. However, weak interface bonding between thermosets and cement hydrates causes significant strength degradation in cementitious composites, which has constituted a long-term stumbling block. Herein, we innovate a green recycling solution for recycling thermoset waste as fillers in order to engineer sustainable cement mortar with the help of a green surface adhesion promoter – a silane coupling agent. The feasibility of the proposed approach was experimentally validated in terms of workability performance and compressive strength in order to meet requirements in practice. The results show that thermoset waste can substitute for at least 15% of sand in cement mortar, following workability requirements. In addition, the optimal replacement level of thermoset waste for sand in cement mortars with the highest compressive strength is 5%, beyond which the compressive strength exhibits a continuing drop. The strength alteration mechanisms are elucidated by scanning electron microscope (SEM) analyses. We demonstrate that the developed thermoset cement mortars with 5% thermoset waste have the great potential to achieve a highly dense microstructure, robust interfacial transition zone, and better hydrate crystal growth, which are the microscopic origins determining the inherent strength enhancement. The findings of this study enable the design of eco-friendly cement mortar formulations, which can both benefit the construction industry and relieve the severe environmental burden caused by landfilling thermoset waste after its end-of-life use. • A novel strategy for recycling thermoset waste into cement mortars is devised. • The interfacial bonding between thermosets and hydrates is enhanced by silanization. • The workability and compressive strength of the cement mortars are evaluated. • The mortars with 10% thermoset show performances on par with control groups. • Microstructural origins behind variations in the compressive strength are revealed. [ABSTRACT FROM AUTHOR]

• Epidemiological data and the WHO guidelines are used to define pandemic periods • Waste recycling and disposal trends are examined using regression and MK tests • COVID-19 virulence negatively correlated with residential waste generation • Compared to collection rate, disposal rate is more sensitive to COVID-19 virulence • The decreasing CWDV trend could indicate an increasing amount of waste diversion This study aims to identify the effects of continued COVID-19 transmission on waste management trends in a Canadian capital city, using pandemic periods defined from epidemiology and the WHO guidelines. Trends are detected using both regression and Mann-Kendall tests. The proposed analytical method is jurisdictionally comparable and does not rely on administrative measures. A reduction of 190.30 tonnes/week in average residential waste collection is observed in the Group II period. COVID-19 virulence negatively correlated with residential waste generation. Data variability in average collection rates during the Group II period increased (SD=228.73 tonnes/week). A slightly lower COVID-19 induced Waste Disposal Variability (CWDW) of 0.63 was observed in the Group II period. Increasing residential waste collection trends during Group II are observed from both regression (b = +1.6) and the MK test (z = +5.0). Both trend analyses reveal a decreasing CWDV trend during the Group I period, indicating higher diversion activities. Decreasing CWDV trends are also observed during the Group II period, probably due to the implementation of new waste programs. The use of pandemic periods derived from epidemiology helps us to better understand the effect of COVID-19 on waste generation and disposal behaviors, allowing us to better compare results in regions with different socio-economic affluences. [ABSTRACT FROM AUTHOR]

There are forecasts for the exponential increase in the generation of carbon fibre-reinforced polymer (CFRP) and glass fibre-reinforced polymer (GFRP) composite wastes containing valuable carbon and glass fibres. The recent adoption of these composites in wind turbines and aeroplanes has increased the amount of end-of-life waste from these applications. By adequately closing the life cycle loop, these enormous volumes of waste can partly satisfy the global demand for their virgin counterparts. Therefore, there is a need to properly dispose these composite wastes, with material recovery being the final target, thanks to the strict EU regulations for promoting recycling and reusing as the highest priorities in waste disposal options. In addition, the hefty taxation has almost brought about an end to landfills. These government regulations towards properly recycling these composite wastes have changed the industries' attitudes toward sustainable disposal approaches, and life cycle assessment (LCA) plays a vital role in this transition phase. This LCA study uses climate change results and fossil fuel consumptions to study the environmental impacts of a thermal recycling route to recycle and remanufacture CFRP and GFRP wastes into recycled rCFRP and rGFRP composites. Additionally, a comprehensive analysis was performed comparing with the traditional waste management options such as landfill, incineration with energy recovery and feedstock for cement kiln. Overall, the LCA results were favourable for CFRP wastes to be recycled using the thermal recycling route with lower environmental impacts. However, this contradicts GFRP wastes in which using them as feedstock in cement kiln production displayed more reduced environmental impacts than those thermally recycled to substitute virgin composite production. [ABSTRACT FROM AUTHOR]