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Journal of Material Cycles and Waste Management
Journal Prestige (SJR): 0.491  Citation Impact (citeScore): 2 Number of Followers: 2  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1611-8227 - ISSN (Online) 1438-4957 Published by Springer-Verlag  [2468 journals]
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- Study on separation of N, F and Al from hazardous aluminum dross by
alkaline roasting-
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Abstract: Herein, fluorine fixation, nitrogen removal, and the alkaline solution recovery of alumina were studied using calcium-based high-temperature soda roasting. In addition, the effects of roasting conditions, dissolution conditions, and additives (carbon alkali and calcium salt) on fluorine fixation and alumina recovery were studied. The results show that when the roasting temperature was 1100 ℃ and the roasting time was 2 h, the dissolution temperature was 80 °C, while the dissolution time was 20 min. The ratio of soda to dross was 1.0, and 30 wt% CaCO3 had been added as a fluorine fixing agent. The Al extraction rate from aluminum dross (AD) reached 86.21%, the denitrification rate reached 99.54%, the concentration of soluble fluoride ion was reduced to 0.111 g·L−1, and the fluoride fixation rate was 75.04 wt%. CaF2 is the main component of the leaching residue, which can be added as an insulation material for electrolysis. Alkaline oxidation roasting and calcium-based fluoride fixation are effective methods to separate aluminum, fluoride, and nitrogen. This study provides a new method for the safe and efficient utilization of AD.
PubDate: 2023-05-30
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- Sequential flotation of 4 components in silicon-based waste solar cells
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Abstract: Si, Al, Cu, and Ag particles’ mixture which mainly composes pulverized silicon-based waste solar cells were individually separated by the batch flotation experiments with high recovery and content, and then a general flow chart of the sequential flotation procedure of n-component was postulated including 2-, 3-, and 4-components. The n-component mixture was separated to 1: n-1 or i: j (i + j = n) by a flotation procedure and n-1 times operation was necessary to divide into the individual component. The first flotation process to separate Al into the froth layer was carried out with a collector of SDS solution after dipping Si, Al, Cu, and Ag mixture into the SDS solution. Si was separated in the froth by the second flotation with a collector of a commercial neutral detergent after Al etching by HCl, and Si, Cu and Ag mixture dipped in the detergent. The Cu and Ag mixture was calcinated at 673 or 773 K and dipped into the detergent, and the third flotation with the collector of the detergent led to Cu in the froth and Ag in the sediment. The 4-component mixture was successfully separated into each component by the 3-consecutive flotation processes.
PubDate: 2023-05-30
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- Physicochemical and compositional analyses of household solid wastes:
opportunities for bioenergy production and sustainable waste management in
Ethiopia-
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Abstract: This study aimed to determine the quantity and quality of source separated organic household solid waste (SSOHSW) generation in Addis Ababa, Ethiopia with particular reference to its bioenergy recovery potential using bioconversion technologies. A multi-stage probability sampling approach was employed to collect data from 304 households representing different socioeconomic backgrounds from March 2 to 9, 2021. Results showed that HSW generation rate was 0.46 kg/capita/day, and the city’s annual generation of HSW was estimated at 648,094 tons, among which, 60.1% and 22.1% were organic, and recyclable wastes, respectively. Multivariate linear regression analysis indicated household income and occupation were significantly positive, whereas family size had a significant negative association with per capita HSW generation rate. Proximate analysis revealed averages of greater than 70% volatile matter content in all test samples. Ultimate analysis findings showed that carbon and oxygen were the major elements in all the test samples whereas compositional analysis of test samples indicated content of hemicellulose (12.11–70.38%) was the highest while lignin (2.33–8.67%) was the lowest. The study findings revealed that source separated household organic municipal solid waste is a suitable feedstock for bioenergy production and sustainable waste management. Using a suitable bioconversion process such as anaerobic digestion technology, 24.6 kJ of electricity is estimated to be obtained daily from the SSOHSW fractions.
PubDate: 2023-05-28
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- Synthesis of artificial aggregates and their impact on performance of
concrete: a review-
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Abstract: Infrastructure development and urbanization have created a demand for the prime construction material—"Concrete." The manufacture of concrete has pressurized the aggregate supply chain for over-exploitation of natural resources leading to eco-detrimental impacts besides environmental regulations. The auxiliary sectors of the construction industry are creating a vast quantum of by-products and waste, causing environmental degradation, which concerns governing bodies. Developing aggregates artificially using these by-products and waste materials would be an eco-friendly and economical solution. This article provides an overview of the ingredients, production methods, and factors influencing the characteristics of such sustainable building materials, which can substitute conventional aggregates in the near future.
PubDate: 2023-05-27
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- Resource recovery potential from source-separated organic municipal solid
waste: opportunities for organic fertilizer production and creating
sustainable urban agriculture in Ethiopia-
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Abstract: Increasing waste production and its disposal into the environment without treatment and resource recovery is considered as a threat to the environment and human health. This study aimed to determine the current commercial and institutional solid waste generation rates, physicochemical and compositional analyses at selected sub-cities in Addis Ababa (Arada, Kirkos and Yeka), Ethiopia and to estimate its nutrient recovery potential for the production of organic fertilizer. The study covered a sample size of 44 commercial and 44 institutional centers. Physiochemical analyses of organic fraction of mixed commercial and institutional solid wastes were determined following standard methods. The study finding showed that the average municipal (commercial and institutional) solid waste generation rates was 0.24 kg/capita/day with 0.33 kg/capita/day and 0.16 kg/capita/day, respectively. The bulk densities of commercial and institutional solid waste were 421.80 kg/m3 and 361.87 kg/m3, respectively. The composition of commercial and institutional solid waste in the selected area was dominated by food waste (42.3%) followed by paper waste (30.8%). Yard & plastic wastes accounted for 9.9% and 8%, respectively. The rest waste fractions were accounted for a total of 9%. The average percentage composition of compostable wastes of the solid waste was significantly high (53%) followed by recyclable wastes (41%). The average value of pH and moisture content of the organic wastes were in the range of 6–7.5 and 47–81%, respectively. With the exception of paper waste, the highest amount of hemicellulose was recorded. Generally, the overall results showed that most of the generated waste was organic, easily biodegradable, and can be suitable feedstocks for processing organic fertilizer through composting.
PubDate: 2023-05-27
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- University students’ awareness of e-waste and its disposal practices in
Pakistan: a construction of the conceptual framework-
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Abstract: Pakistan is among the few countries generating and receiving enormous e-waste, which posits a threat to its future generations. A systematic literature review also suggests exploring e-waste awareness in Asia to understand awareness and behavior. Therefore, the present study explored university students’ awareness of e-waste and the factors hindering the disposal of laptops, personal computers, and cellphones and suggested a conceptual framework. The study used the qualitative research approach and non-probability sampling. We collected data through four focus group discussions (FGDs) with students at a Pakistani university. After data saturation, we developed themes from FGDs and found computer sciences and engineering students with better awareness than others. The factors hindering e-waste disposal were lower monetary benefits for disposal, breach of sensitive information, nostalgic association with devices, and non-availability of disposal facilities. Other variables like lower resale value and high family sharing increased the storage of e-devices and reduced e-waste disposal. The research is among a few initial attempts to explore e-waste awareness and factors hindering disposal behavior in e-waste-receiving countries (e.g., Pakistan) and provides evidence from students who are the primary users. Our findings are crucial for policymakers to take corrective actions, introduce monetary benefits, and secure disposal to reduce e-waste.
PubDate: 2023-05-27
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- Optimization of oil yield from isothermal pyrolysis of waste polystyrene
over CuO/Kaolin-
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Abstract: Isothermal pyrolysis of waste polystyrene over CuO/kaolin was investigated and optimized for maximum oil yield using Box-Behnken response surface design. The results revealed that the reaction variables affect the yields of the gaseous, liquid and char, respectively. Optimization of the reaction variables predicted an optimal yield of 96.07% at a residence time, heating rate, and catalyst loading of 45 min, 10 °C/min and 30%, respectively in agreement with the validation results of 95.56 ± 1.90%. The physicochemical properties of the oil conformed with petrodiesel properties and could be used as its substitute. The oil has a 84% dominance of benzene,1,1-(1-butenylidene)bis, and the mechanism through which it was formed has been proposed.
PubDate: 2023-05-26
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- Recycling or chemical stabilization' Greenhouse gas emissions from
treatment of waste containing mercury under the Minamata Convention-
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Abstract: Appropriate management of waste containing mercury is important. However, reducing greenhouse gases (GHGs) associated with this process is equally important, warranting research into waste management methods that emit the least amount of GHGs. We evaluated GHG emissions from recycling systems of spent fluorescent lamps and dry cell batteries discarded by households in Japan using a life cycle assessment technique. The results show significant GHG reduction from resource recovery; therefore, it is essential to ensure that resource recovery is conducted properly. Regarding the spent fluorescent lamp recycling system, the transportation process contributes a large amount of GHG emissions if the waste is not crushed. It is recommended that they be crushed before being transported to improve transportation efficiency. The larger the population of a city, the lower the per-capita collection of waste containing mercury. Due to the hazardous nature of mercury, it is necessary to encourage its separate collection. The demand for mercury will decrease in the future, and it is possible that collected mercury will be disposed of through chemical stabilization. This study clarifies no significant, less than 0.01 kg-CO2e/kg-waste, increase in GHG emissions associated with the transition from mercury recycling to chemical stabilization.
PubDate: 2023-05-26
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- Low-carbon utilization of coal gangue under the carbon neutralization
strategy: a short review-
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Abstract: The treatment and utilization of coal gangue, one of the main solid wastes produced during coal mining, are of great significance in environmental protection and resource development. In the contemporary context of the carbon neutralization strategy, due to the property of the carbon in coal gangue, it is necessary to be cautious of the carbon effect during its treatment and utilization process. To grasp the concept of the carbon effect of coal gangue more comprehensively and systematically and provide more economic and reasonable technical strategies for the treatment and utilization of coal gangue against the background of carbon neutralization, this study systematically summarizes the research results from three aspects: the carbon emission risk of coal gangue itself, the carbon emission risk during its treatment and utilization process, and the potential effect of the application carbon sequestration. There are many types of carbon emission risks when considering coal gangue itself, such as direct carbon emissions resulting from spontaneous combustion and extended carbon emissions due to its negative pollution impacts on soil and vegetation. At present, the main utilization modes of coal gangue include fuel, building materials, filling materials, and ecological materials. Most of them have certain carbon emission risks, while some of them also have certain carbon fixation effects. Against the background of the carbon neutralization strategy, the treatment and utilization of coal gangue should focus on three aspects: its own carbon-free emissions; its carbon absorption effect and low-carbon emission in the treatment process; and taking comprehensive technical measures, such as the oxidation inhibition of coal gangue, enhancement of the ecological carbon sink function, excavation of the carbon absorption function, and nearby utilization and pollution prevention and control, to achieve high value and low-carbon release in the treatment and utilization of coal gangue.
PubDate: 2023-05-25
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- Life cycle assessment of source separation of biowaste, pay as you throw
systems and autonomous composting units in the Municipality of Katerini,
Greece-
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Abstract: Nowadays, composting technologies are being used to manage food waste (FW), which is an environmentally friendly method of waste management in which organic matter can decompose biologically. The BIOWASTE project promotes the transfer and application testing of innovative technologies (PAYT and ACUs), aiming to enhance management efficiency in solid waste-related issues, such as source separation schemes and treatment systems emphasizing organic waste. The proposed systems were introduced in the Municipality of Katerini. Ιn the framework of the BIOWASTE project, the Municipality of Katerini developed a detailed pay-as-you throw (PAYT) system and installed two Autonomous Composting Units (ACUs) in decentralized communities to receive the biowaste produced directly without the need for collection. ACUs are small closed integrated composting units that neutralize effluent and expanding liquids. The aim of this paper is to present the results of a case study dealing with the life cycle environmental assessment of the PAYT system and autonomous composting of food waste in decentralized communities of the Municipality of Katerini, Greece. The results of the study indicate that autonomous composting is environmentally preferable over landfill, the current organic waste management practice in Greece. Each ton of biowaste diverted from landfill, due to mechanical composting, saves 0.21 t CO2 eq.
PubDate: 2023-05-23
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- Mechanical properties of shotcrete with addition of sugarcane bagasse
fiber and ash-
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Abstract: Shotcrete is a sprayed concrete placed on steep slopes that have been widely used because it can prevent surface weathering and erosion, and in some cases, small-scale control rock falls. However, shotcrete is usually thin, and it is directly affected by the surrounding environment, resulting in cracks. In this study, sugarcane residues (bagasse fiber and ash) were applied in shotcrete, and mechanical properties were investigated. The results showed that shotcrete with addition of sugarcane residues, obtained similar or better mechanical strength than the control mixture.
PubDate: 2023-05-23
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- Experimental research on compressibility characteristics of recycled
concrete aggregate: recycled tire waste mixtures-
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Abstract: The utilization of processed rubber and construction waste in lieu of soil as a substrate could improve significantly seismic performance, while addressing the pressing environmental issue of how to reutilize and dispose of, i.e., automotive tires and demolition by-products. In this study, a series of laboratory tests explore the influence of recycled tire waste (RTW) and recycled concrete aggregate (RCA) fine particles on the compressibility parameters of RCA–RTW mixtures. The results revealed that the addition of rubber waste to RCA causes an increase in its compressibility and consolidation index (cv) while prompting a power law decrease in the associated void ratio. It is found that all RCA–RTW mixtures are characterized by higher values of the compression (CC) and swelling (CS) indexes when compared to the pure RCA specimens while presenting a primary and secondary constrained modulus of fewer than 42 MPa and 96 MPa, respectively.
PubDate: 2023-05-22
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- Study on mechanical properties and microstructure of recycled fine
aggregate concrete modified by Nano-SiO2-
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Abstract: In this study, the effects of different contents of Nano-SiO2 (NS) on a slump, compressive strength, splitting tensile strength, flexural strength, hydration products, and microstructure of recycled fine aggregate concrete (RFAC) were investigated. The results show that the addition of recycled fine aggregate (RFA) has a significant negative impact on the mechanical properties of concrete, but with the addition of NS, the mechanical properties of RFAC are improved. When the content of NS is 3%, the compressive strength, splitting tensile strength and flexural strength at 28 d of RFAC increased by 30.7%, 35.1%, and 18.7% respectively, and the durability was also improved significantly. Meanwhile, Thermogravimetric differential scanning calorimeter (TG-DSC), and X-Ray diffraction analysis (XRD) demonstrated that the addition of NS reduced the content of calcium hydroxide (CH) crystal in RFAC samples. Scanning electron microscopy (SEM) results show that NS doping can refine CH crystal, adsorb hydration products and improve the compactness of RFAC microstructure. The maximum efficiency is obtained when the content of NS is 3%. This study aims to research the possibility of using 100% recycled fine aggregate (RFA) in concrete and helps to maintain the better mechanical properties and durability of RFAC for a longer time.
PubDate: 2023-05-22
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- Prediction of greenhouse gas emissions from municipal solid waste
incinerators with consideration of utilization of heat and captured CO2 in
the Tokyo waterfront area-
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Abstract: We focused on incineration of solid waste and resource recycling, when clarifying how to achieve carbon neutrality (CN) by 2050; we describe how future municipal solid waste incinerators (MSWIs) should operate. Specifically, eight low-carbon measures were set for four MSWIs located in the Tokyo waterfront area (Chuo, Minato, Shinkoto, and Ariake), and greenhouse gas (GHG) emissions were estimated for each scenario by combining these measures. We concluded that, in addition to MSW reduction and the introduction of biomass plastics, the improvement of power generation efficiency via plant renewal and wide area management of the MSWIs are useful when seeking to achieve CN. If the emission factor of electricity is to achieve CN in the future, the introduction of methanation is desirable in combination with wide area management, but if the emission factor of city-gas is also expected to achieve CN, an expansion of district heat utilization should rather be considered.
PubDate: 2023-05-22
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- Eco-friendly green composites reinforced with recycled polyethylene for
engineering applications-
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Abstract: Polyethylene (PE) and cement are industrial products that promote environmental pollution. These products when exposed on the landfill have tremendous effects on the lives of humanity and other living creatures, including animals. Therefore, this research presents the results of experimental and theoretical modeling of green composites (without the inclusion of cement) reinforced with recycled polyethylene waste for applications in the Mechanical and Civil Engineering industry. The composites are produced using different weight fractions of laterite and molten PE mixed homogeneously to produce unique green composites with excellent mechanical properties. The green composite with 40 wt.% laterites and 60 wt.% PE exhibited the highest compressive strength, flexural strength and fracture toughness of 25 MPa, 7.3 MPa and \(0.6 MPa\sqrt{m}\) , respectively. Additionally, the green composite recorded maximum yield stress of \(\sim 2 MP\) . The maximum yield stress of the green composites falls under the minimum range of yield stress for traditional concrete structures. The SEM images reveal evidence of bonding and ligament bridging in the green composites reinforced with 40 wt.% laterites and 60 wt.% PE. The probability distribution plots show that the polyethylene in the green composites follows the Weibull distribution with low Anderson Darling Statics and p-values greater than significance level of 5%. Graphical abstract
PubDate: 2023-05-21
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- Using machine learning method to predict food waste in catering industry
under high resolution: a case in Dongguan-
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Abstract: Waste classification is comprehensively carried out in China as an important national-level policy, and the large amount and the wide range of food waste generation (FWG) cause problems in the collection, transportation, and treatment. This study has conducted the prediction of FWG from the catering industry under high resolution, and provided suggestions and insights for food waste management and treatment. Taking Dongguan as an example, a Back Propagation Network (BPN) model is used to predict FWG under different operation data, and based on the acquired theoretical FWG numerical distribution, the intervals used to divide FWG values are determined. Then a Random Forest (RF) model is applied to predict the FWG intervals of the restaurants in the Point of Interest (POI) data. FWG of 96,303 restaurants is predicted, and the predicted FWG from the catering industry is about 3,106 t per day. Variation of FWG in different categories of restaurants, the material flow of FWG at the restaurant level, patterns of FWG at the restaurant level, and spatial patterns of FWG at the city level are also investigated. Suggestions for improvement of food waste collection standard and source reduction of FWG, and insights into food waste collection and distributed treatment system are raised. Graphical abstract
PubDate: 2023-05-20
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- The impact of cognitive aversion toward mercury on public attitude toward
the construction of mercury wastes landfill site-
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Abstract: Minamata convention on mercury requests mercury wastes landfilling in environmentally safe manners. Owing to great difficulties to form public acceptance of landfill site construction, this study focused on emotional appraisal to mercury. The author quantitatively evaluated cognitive aversions toward mercury and other harmful/hazard-like objects like dioxin using two types of pairwise comparison methods. The results of both methods showed good agreement. Mercury received the second strongest aversion, following radioactive wastes. Gender and age gave no significant impact on mercury aversion at 5% significance level. When perceived knowledge of mercury was neutral or positive, higher awareness resulted in stronger mercury aversion. In contrast, mercury aversion was almost constant regardless of negative level of the awareness. When the attitude toward construction of mercury waste landfill site was mitigated from rejection to neutral, mercury aversion decreased. On the other hand, mercury aversion increased when the attitude was shifted from neutral to acceptance. Rejection attitude might be affected by mercury aversion. In contrast, acceptance attitude was formed by rational consideration of mercury landfill necessity, not weak aversion. To design a supporting process for public acceptance formation, stronger mercury aversion perceived by both acceptance and rejection attitude persons should be concerned.
PubDate: 2023-05-20
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- 100-year simulation of mercury emissions from landfilled stabilized
mercury waste-
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Abstract: Owing to Minamata Convention on mercury, the final disposal of mercury in environmentally safe manners will be required. Mercury disposal in landfill sites will be one of the feasible options but its environmental risk has been strongly concerned. This study built a model including hydraulic flows of rain infiltration from the top surface, unsaturated percolation in the landfill body, leachate discharge from the collection pipe, mercury transfer including diffusion and sorption, and chemical/biological reactions of mercury species to simulate mercury emissions from a mercury landfill site. Mercury emissions via landfill leachate and landfill gas to the atmosphere were simulated. The model was validated using lab-scale lysimeter experiment data. The model predicted that the major emission pathway of mercury to the environment is landfill leachate, which accounted for 99.8% of the total emissions. 83% of mercury in the leachate was estimated to be inorganic form and the rest 17% was methylmercury. The simulation suggested that mercury emission exceeds the environmental standard after the 16th year. Long-term monitoring of the leachate is necessary even when no mercury detection continues for 16 years. The model proposed that rainwater infiltration control on the top surface is very effective to reduce mercury emissions.
PubDate: 2023-05-20
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- What attributes of mandatory waste management policy can enhance the
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Abstract: China is facing a severe waste siege. Notwithstanding the several years of mandatory policy implementation, the residents’ waste separation intention remains insignificantly enhanced. Consequently, it is urgent to theoretically answer the question of what type of mandatory policy is most effective. Thus, in the current research, we propose the mandatory policy as a combination of five attributes, that is, economic penalty, social penalty, supervision, charging, and community governance, and conduct a policy choice experiment with 354 participants. The results of the randomized conjoint analysis show that economic penalty, supervision, and community governance are influential determinants of separation intention. The mandatory policy has an interaction effect with auxiliary policies; specifically, community governance and supervision are more effective, while residents are also more willing to pay fines when a points redemption policy or a well-developed infrastructure system is present. The effect of mandatory policy also varies across residents. Females, highly educated, or high-income individuals are relatively more inclined to separate waste, while elders, renters, and residents who have lived in an environment for more than 20 years are less likely to separate. The results of the welfare gain analysis show that strengthening the penalty, supervision, and community governance are also helpful toward improving social welfare. In order for mandatory policies to work better, it is important to continuously improve community governance, raise the cost of violations, vigorously promote waste supervision, perfect the reward mechanism, and improve waste separation infrastructure.
PubDate: 2023-05-19
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- Electrical and electronic equipment consumption pattern and e-waste
disposal behaviour of individuals and households in India-
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Abstract: Despite electronic waste (e-waste) rules in force, there is still a huge gap in awareness among communities about the handling of discarded Electrical and Electronic Equipment. Understanding consumer perception about e-waste disposal and its flow holds a vital role in efficient e-waste management in a developing nation like India, where e-waste generation is rapidly increasing. The current study is based on a nationwide survey of consumer consumption patterns, awareness and disposal behaviour. A survey is conducted with a sample size of 491 respondents from urban, semi-urban and rural India with an annual household income of more than INR 0.5 million. Data about individuals and households are captured along with other useful primary data to measure consumer behaviour towards e-waste disposal methods. The results show that resident’s education level and age significantly correlate with a possible cause of e-waste disposal behaviour. A limited number of consumers have adopted the formal disposal method, whereas the informal disposal system is prevalent and dominant in all regions. This research provides a scientific analysis of the various choices and preferences of e-waste disposal methods. It is expected to help policymakers and stakeholders to adopt more effective public e-waste disposal rules. Graphical abstract
PubDate: 2023-05-18
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