Waste treatment

废物处理
  • 文章类型: Journal Article
    重复使用,recovery,由于各种经济和环境效益,鼓励回收报废车辆(ELV)。汽车再制造是一种特定的循环营销系统,用于回收零件的再利用,可以为拆解公司和消费者带来经济利益。本研究旨在揭示电力报废处理的经济和环境效益,混合动力车,传统乘用车。这项研究基于物料流分析(MFA)对ELV零件的再利用进行了经济评估,并对立陶宛市场上这些零件的价格进行了实际分析。使用MFA对ELV零件的再利用进行了环境评估,生产不同材料的二氧化碳当量,和生命周期评估方法。结果表明,38%的电动和混合动力车部件,以及27%和28%的柴油和汽油动力ELV零件,分别,可以出售(重复使用)。所有四种类型的ELV的经济利益可以为拆解者和乘用车消费者节省多达12,739欧元和51,281欧元。分别。最大的二氧化碳节约来自电动ELV部件的再利用,而最低的节省来自汽油ELV。
    Reuse, recovery, and recycling of end-of-life vehicles (ELVs) are encouraged owing to various economic and environmental benefits. Automotive remanufacturing serves as a specific circular marketing system for the reuse of recovered parts that can bring economic benefits for both dismantling companies and consumers. This study aimed to reveal the economic and environmental benefits of the end-of-life treatment of electric, hybrid, and conventional passenger cars. This research presents an economic assessment of the reuse of ELV parts based on a material flow analysis (MFA) and a practical analysis of the prices of these parts in the Lithuanian market. The environmental assessment of the reuse of ELV parts was performed using an MFA, the CO2 equivalents for the production of different materials, and a life cycle assessment methodology. The results showed that 38% of all electric and hybrid ELV parts, and 27% and 28% of diesel- and petrol-powered ELV parts, respectively, can be sold (reused). The economic benefit across all four types of ELVs could amount to savings of up to 12,739 Eur and 51,281 Eur for the dismantlers and passenger car consumers, respectively. The greatest CO2 savings result from reusing the parts of electric ELVs, whilst the lowest savings come from petrol ELVs.
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  • 文章类型: Journal Article
    Effective and efficient urban waste management systems (WMSs) are a cornerstone for a sustainable society. Life cycle costing (LCC) provides a useful framework for the joint analysis of economic and environmental impacts of a WMS, by considering both financial and external costs. The present study applies the methodology of societal LCC to the WMS of the Italian region of Emilia-Romagna to provide a case study on how the available information on waste flows and budget costs of a real WMS can be used to obtain an estimate of the total cost of waste management, including externalities. The results evidence that the main source of negative externality in the analyzed WMS is the transportation of waste, with only a minor role of external burdens due to incinerators and landfills. However, the positive externality resulting from recycling more than compensates those impacts, leading to a net external benefit associated to the WMS. The contribution of both uncertain unit external costs and environmental benefits imputable to recycled materials to the overall uncertainty of the result is systematically investigated by parametric uncertainty analysis. The most critical parameters in determining the sensitivity of the result are the monetary values attributed to primary energy consumption and CO2 emissions, together with assumptions on energy savings related to recycling. Eventually, it is shown how the developed LCC model can be used as decision-support tool to preliminarily investigate the implications of alternative management options on the financial and external costs of the WMS.
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  • 文章类型: Journal Article
    The amount and type of municipal solid waste (MSW) in Bahía Blanca (Argentina) were assessed and correlated with population socioeconomic level. In this sense, seven areas with different quality of life were selected. In addition, a parallel study on a control area was performed and validated for obtaining a representative result to provide analogous conclusions for the whole city. From this study, a combination of sorting methodologies is proposed in order to reduce the actual amount of waste sent to landfill. If these methodologies are implemented in Bahia Blanca city, MSW in landfill could be reduced at least 80%. The proposed strategy is to combine waste sorting at source and at destination. An alternative separation at source could be proposed as follows: packaging (including plastic, cans and Tetra Pak), other plastics, paper and glass. The rest of MSW could be included in a container which would be collected daily or three times a week without changing inhabitants\' habits and promoting their collaboration. Then, it could be separated at destination for waste-to-energy, composting, and biogas obtaining. Residuals from incinerators and biogas/composting plants would be sent to landfill. On the other hand, regarding the relationship between the proposed strategy and population quality of life, obtained results from this study could be useful to size and to efficiently locate disposal bins/containers for source separation as well as to redesign routes of municipal solid waste collection. Also, this strategy allows to add value to different components of MSW, improving working conditions of waste workers and creating new jobs in Bahia Blanca city.
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  • 文章类型: Journal Article
    工业塑料废物在环境中的积累是全球日益关注的问题。热化学工艺是处理塑料废物的首选方法,主要是因为它可以减少废物的体积;然而,塑料废物的热化学处理会排放有害的化学物质,如苯衍生物和多环碳氢化合物。为了克服这一挑战,负载型金属催化剂(碳载Pd和Pt催化剂)用于抑制聚对苯二甲酸乙二醇酯(PET)热解形成多环化合物和联苯衍生物。在Pd或Pt催化的PET热解过程中产生的多环化合物和联苯衍生物比非催化的PET热解少。在700°C下,Pt催化热解的多环化合物和联苯衍生物的浓度比非催化热解低107%和56%,分别。在400至800°C的温度下,Pt催化剂比Pd催化剂更有效地抑制PET热解过程中多环化合物和联苯衍生物的产生。这可能是因为Pt位点催化脱环反应和/或自由基机理,其在含碳物质如PET的热裂化中占主导地位。这项研究的结果将有助于通过热化学过程开发环境友好的工业塑料废物处理方法。
    The accumulation of industrial plastic waste in the environment is a global growing concern. Thermochemical process is a preferred method to dispose plastic waste mainly because it can reduce volume of the waste; however, the thermochemical disposal of plastic waste can emit harmful chemical species such as benzene derivatives and polycyclic hydrocarbons. As an effort to overcome this challenge, supported metal catalysts (carbon-supported Pd and Pt catalysts) were used to inhibit the formation of polycyclic compounds and biphenyl derivatives by pyrolysis of polyethylene terephthalate (PET). Less polycyclic compounds and biphenyl derivatives were generated during the Pd or Pt-catalyzed PET pyrolysis than non-catalytic PET pyrolysis. The concentrations of polycyclic compounds and biphenyl derivatives were 107 % and 56 % lower for the Pt-catalyzed pyrolysis at 700 °C than non-catalytic pyrolysis, respectively. The Pt catalyst was more effective to suppress the generation of polycyclic compounds and biphenyl derivatives during the PET pyrolysis than the Pd catalyst at temperatures from 400 to 800 °C. This was likely because the Pt sites catalyzes decyclization reaction and/or free radical mechanism that is dominant in thermal cracking of carbonaceous substances such as PET. The results of this study would help develop environmentally friendly industrial plastic waste treatment methods via thermochemical processes.
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  • 文章类型: Journal Article
    This paper presents the investigation of metals production form artificial ore, which consists of printed circuit board (PCB) waste, processed in plasmatron plasma reactor. A test setup was designed and built that enabled research of plasma processing of PCB waste of more than 700 kg/day scale. The designed plasma process is presented and discussed. The process in tests consumed 2 kWh/kg of processed waste. Investigation of the process products is presented with their elemental analyses of metals and slag. The average recovery of metals in presented experiments is 76%. Metals recovered include: Ag, Au, Pd, Cu, Sn, Pb, and others. The chosen process parameters are presented: energy consumption, throughput, process temperatures, and air consumption. Presented technology allows processing of variable and hard-to-process printed circuit board waste that can reach up to 100% of the input mass.
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  • 文章类型: Journal Article
    The rapid increase in anthropogenic nitrogen (N) load in urbanized environment threatens urban sustainability. In this study, we estimated the amount of reactive N (Nr) as an index of N pollution potential caused by human activities, using the megacity of Beijing as a case study. We investigated the temporal changes in Nr emissions in the environment from 2000 to 2012 using a multidisciplinary approach with quantitative evaluation. The Nr emissions presented slightly increasing during study period, and the annual emission was 0.19 Tg N, mainly resulting from fuel combustion. Nevertheless, the Nr output intensity resulting from inhabitants\' livelihoods and material production had weakened over the study period. The evaluation results showed that the environmental measures to remove Nr in Beijing were efficient in most years, suggesting that progress in mitigating the growth of the Nr load in this urban environment was significant. Further measures based on N offset are suggested that could help alleviate the environmental pressure resulting from anthropogenic Nr emissions. These could provide theoretical support for the sustainable development of megacities.
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  • 文章类型: Journal Article
    处理来自城市固体废物焚烧(MSWI)的灰可能相当麻烦。一些灰分馏分含有有机污染物,比如二恶英,以及有毒金属。此外,一些金属具有很高的价值,被认为对工业至关重要。回收铜,MSWI骨灰中的锌和铅,例如,不仅会提供原本将被填埋的有价值的金属,而且还会产生具有较低浓度的有毒金属的灰分残留物。在这项工作中,来自MSWI设施的粉煤灰和底灰用于研究和优化使用不同溶液(硝酸,盐酸和硫酸)和参数(温度、控制pH值,浸出时间,和液体/固体比)。发现盐酸在20°C下在不到24小时内从粉煤灰中溶解铜(68.2±6.3%)和锌(80.8±5.3%)相对有效。还实现了镉和铅的有效浸出(分别超过92%和90%)。来自相同燃烧单元的底灰也被表征并使用酸浸出。金属产率适中,渗滤液倾向于形成凝胶状沉淀物,这表明溶液实际上相对于某些组分是过饱和的。这种凝胶形成将导致进一步的金属纯化过程的问题,例如溶剂萃取。
    Ash from municipal solid waste incineration (MSWI) may be quite cumbersome to handle. Some ash fractions contain organic pollutants, such as dioxins, as well as toxic metals. Additionally, some of the metals have a high value and are considered as critical to the industry. Recovery of copper, zinc and lead from MSWI ashes, for example, will not only provide valuable metals that would otherwise be landfilled but also give an ash residue with lower concentrations of toxic metals. In this work, fly ash and bottom ash from an MSWI facility was used for the study and optimization of metal leaching using different solutions (nitric acid, hydrochloric acid and sulfuric acid) and parameters (temperature, controlled pH value, leaching time, and liquid/solid ratio). It was found that hydrochloric acid is relatively efficient in solubilizing copper (68.2±6.3%) and zinc (80.8±5.3%) from the fly ash in less than 24h at 20°C. Efficient leaching of cadmium and lead (over 92% and 90% respectively) was also achieved. Bottom ash from the same combustion unit was also characterized and leached using acid. The metal yields were moderate and the leachates had a tendency to form a gelatinous precipitate, which indicates that the solutions were actually over-saturated with respect to some components. This gel formation will cause problems for further metal purification processes, e.g. solvent extraction.
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  • 文章类型: Journal Article
    The problem of chromium slag pollution is a great challenge for China. It is now an urgent task for China to take effective measures to eliminate chromium slag pollution. This article examines the case of the treatment of chromium slag in Shandong Province and explores how chromium slag pollution can be eliminated in Shandong Province. It shows that the chromium slag stockpiled by the chemical plants was successfully utilised by local steel companies, who act as \'scavenger companies\'. The driving mechanism, seeking a potential \'scavenger company\' within the local region and the role of the local government on the case of Shandong Province are discussed. This article concludes that local steel companies can be utilised to effectively and efficiently treat the chromium slag while benefiting the steel companies. The local governments need to play multiple roles in solving the problem of chromium slag pollution. Seeking and identifying \'scavenger companies\' within a region could be an important approach to reducing pollution within the region.
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