电子与电器废弃物资源化处理技术

当今世界电子、电器工业快速发展,层出不穷的技术创新与持续膨胀的市场需求加速了电子与电器设备的更新换代,产生了大量的电子与电器废弃物(WEEE).鉴于WEEE所带来的严重的环境问题及其所含有的金属、贵金属、塑料及玻璃等高利用价值的材料,对WEEE进行资源化再循环处理已成为人们关注的热点.WEEE组成材料在密度、铁磁性、导电性等物理性质方面的较大差异使采用环境友好的机械物理方法对其进行资源化再循环处理成为可能.就WEEE拆解及其所含物质机械物理分离研究进展进行了综述.     

Characterisation of polymer fractions from waste electrical and electronic equipment (WEEE) and implications for waste management

There is an increasing interest in the end-of-life management of polymers present in waste electrical and electronic equipment (WEEE). This is mainly due to high recycling and recovery quotas set by the European WEEE directive, which can only be fulfilled by including the plastic fraction in recycling and recovery approaches. Previous studies identified a high material diversity and various contaminants in WEEE plastics, including heavy metals, polybrominated biphenyls (PBB), diphenyl ethers (PBDE), as well as polybrominated dibenzodioxins and dibenzofurans (PBDD/F). These substances are regulated by European directives that limit their levels in marketable products. Consequently, both material diversity and contaminants are strong arguments against material recycling and point to hazardous waste treatment. However, recent developments in the production of flame retardants and electrical and electronic goods aimed to reduce contaminants and material diversity. Thus, the present study summarises updated contaminant levels of plastic fractions of European WEEE, as well as data on materials in waste housing polymers. Material characterisation revealed housing fractions to be interesting sources for polymer recycling, which however has to implement potent material separation and/or bromine elimination techniques. With respect to contaminants, our data indicate an effective phase-out of PBB, but still high levels of PBDE and PBDD/F are found. Sources and implications for the material recycling and thermal recovery approaches are discussed in detail.     

WEEE closed-loop supply chain network management considering the damage levels of returned products

Environmental Science and Pollution Research - Due to economic, social, and environmental concerns, managing waste electrical and electronic equipment (WEEE) has become an important research area....     

Novel trends in the thermo-chemical recycling of plastics from WEEE containing brominated flame retardants

Environmental Science and Pollution Research - The amount of plastics from waste electric and electronic equipment (WEEE) has enormously increased nowadays, due to the rapid expansion and...     

A bibliometric analysis on waste electrical and electronic equipment research

Environmental Science and Pollution Research - Waste electrical and electronic equipment (WEEE) contains both toxic and valuable materials. Due to rapid development of information and communication...     

Environmental product attributes in end-of-life management in the UK. Part I: an end-of-life eco-declaration for waste IT and office equipment

The focus of this paper and its companion (Part II) is to identify producer responsibility associated with the proposed Waste from Electrical and Electronic Equipment (WEEE) Directive and the need for greater information about the environmental attributes of electrical and electronic equipment to facilitate end-of-life management of discarded products. Recently, a wide-ranging debate has started within the IT industry centred on the best way to define the exact nature of the information that needs to be supplied to recyclers by producers in order to comply with the proposed European Commission Directive. Using IT and office equipment as an indicative example, semi-structured telephone interviews were conducted with representatives of the UK electronics end-of-life management industry about the environmental attributes that are needed for compliance with the draft Directive. The results of this research indicate there is specific information about equipment that is required on a regular basis, the most important of which is centred on hazardous substances and materials contained in whole units, parts and components of that equipment. The content of an eco-declaration for end-of-life management of IT and office equipment derived from quantitative and qualitative interview data is presented.     

我国电子废弃物管理与资源化对策

电子废弃物对人类环境的影响,已成为全球化的问题。通过对发达国家关于电子废弃物管理以及资源化技术的进展回顾,针对我国目前的情况提出相应的对策:制定延伸生产者责任以及有害物质的停用限期的相应法规;建立电子废弃物回收网络体系;通过国家政策和经济的扶持,尽快建立专门处理电子废弃物的机构;加快我国电子废弃物处理技术的步伐,尽快提高现有工艺及设备。     

Revisiting e-waste management practices in selected African countries

ABSTRACT

African countries are among the prime destinations of electronic waste (e-waste) also called Waste of Electrical and Electronic Equipment (WEEE), and have been challenged with the management of its environmental and health impacts. This paper was carried out to understand the e-waste sector and policy responses in selected African countries. Data for the study were generated from sources; such as policy documents, legislations and literature. Findings show that the import of WEEE is on rising in Africa while landfill and incineration continued to be widely used handling approaches. Countries studied lack WEEE specific national policies and stringent policy instruments to enforce proper collection and recycling systems. Despite the start-ups in emerging recycling operations, a major gap is that informal e-waste actors dominate the e-waste chain from collection to material extraction and refurbish activities through rudimentary tools that cannot detect toxic elements. Tackling the problem demands integrated multi-actor interventions with multiple stakeholders to reduce WEEE inflow on one hand, and ramping up safe recycling capacity on the other hand.     

Transformation of tetrabromobisphenol A in the presence of different solvents and metals

Solvent-based separation method is presumably an efficient and environmentally beneficial approach for elimination of brominated flame retardants (BFRs) from waste electrical and electronic equipment (WEEE). The overall goal of this study was to evaluate possible effects of organic solvent on the behavior of BFRs during solvent-based processing of WEEE. We initiated a set of batch experiments for examining the rates and possible pathways of transformation of a representative BFR (tetrabromobisphenol A, TBBPA) using acetone, toluene, and methanol as the solvents. Our results showed that toluene and methanol had no effect on the transformation of TBBPA, but approximately 20% of TBBPA (100 mg L⁻¹) was transformed by acetone within 2 h at 50 °C. Analysis of the products with GC-MS showed that two high-molecular-weight products (MW = 586) were major products of the transformation reactions. The role of acetone as a reactant in the transformation of TBBPA was further validated with dueterated acetone. In addition, the effects of co-existing metals in WEEE (i.e., Zn, Cu, and Ni) on the transformation of TBBPA in the solvent systems were investigated. These metals tested were found to greatly enhance the rates of TBBPA transformation. The metal facilitated solvent reactions with TBBPA may lower the extractability of TBBPA by formation of larger and less soluble products, hence potentially increasing the cost for separating the chemical from WEEE.     

Heavy metal contamination characteristic of soil in WEEE (waste electrical and electronic equipment) dismantling community: a case study of Bangkok,Thailand

Sue Yai Utit is an old community located in Bangkok, Thailand which dismantles waste electrical and electronic equipment (WEEE). The surface soil samples at the dismantling site were contaminated with copper (Cu), lead (Pb), zinc (Zn), and nickel (Ni) higher than Dutch Standards, especially around the WEEE dumps. Residual fractions of Cu, Pb, Zn, and Ni in coarse soil particles were greater than in finer soil. However, those metals bonded to Fe-Mn oxides were considerably greater in fine soil particles. The distribution of Zn in the mobile fraction and a higher concentration in finer soil particles indicated its readily leachable character. The concentration of Cu, Pb, and Ni in both fine and coarse soil particles was mostly not significantly different. The fractionation of heavy metals at this dismantling site was comparable to the background. The contamination characteristics differed from pollution by other sources, which generally demonstrated the magnification of the non-residual fraction. A distribution pathway was proposed whereby contamination began by the deposition of WEEE scrap directly onto the soil surface as a source of heavy metal. This then accumulated, corroded, and was released via natural processes, becoming redistributed among the soil material. Therefore, the concentrations of both the residual and non-residual fractions of heavy metals in WEEE-contaminated soil increased.     

废电子电器回收处理体系研究

分析了废电子电器回收处理体系的问题,提出了一种适合我国国情的废电子电器回收处理体系模式,并对国家对废电子电器回收处理体系的支持问题进行了讨论。     

Integrated bioleaching of copper metal from waste printed circuit board—a comprehensive review of approaches and challenges

Waste electrical and electronic equipment (e-waste) is the most rapidly growing waste stream in the world, and the majority of the residues are openly disposed of in developing countries. Waste printed circuit boards (WPCBs) make up the major portion of e-waste, and their informal recycling can cause environmental pollution and health risks. Furthermore, the conventional disposal and recycling techniques—mechanical treatments used to recover valuable metals, including copper—are not sustainable in the long term. Chemical leaching is rapid and efficient but causes secondary pollution. Bioleaching is a promising approach, eco-friendly and economically feasible, but it is slower process. This review considers the recycling potential of microbes and suggests an integrated bioleaching approach for Cu extraction and recovery from WPCBs. The proposed recycling system should be more effective, efficient and both technically and economically feasible.     

Status of electronic waste recycling techniques: a review

Environmental Science and Pollution Research - The increasing use of electrical and electronic equipment leads to a huge generation of electronic waste (e-waste). It is the fastest growing waste...     

Trends in the management of waste tyres and recent experimental approaches in the analysis of polycyclic aromatic hydrocarbons (PAHs) from rubber crumbs

The health and environmental consciousness of waste tires has increased tremendously over the years. This has motivated efforts to develop secondary applications that will utilize tire when they reach the end of their life cycle and limit their disposal in landfills. Among the applications of waste tires which are discussed in this review, the use of rubber crumbs in artificial turf fields has gained worldwide attention and is increasing annually. However, there are serious concerns regarding chemicals that are used in the manufacturing process of tires, which ultimately end up in rubber crumbs. Chemicals such as polycyclic aromatic hydrocarbons (PAH) and heavy metals which are found in rubber crumbs have been identified as harmful to human health and the environment. This review paper is intended to highlight some of the methods which have been used to manage waste tire; it also looks at chemicals/materials used in tire compounding which are identified as possible carcinogenic.

     

Post-combustion syntheses of PCDD/F and PBDD/F from halogen-rich fuel is suppressed by a pebble heater technology

GOAL, SCOPE AND BACKGROUND: Changes in German and European legislation shifted processing of polymer-rich shredding residues (SR) from landfill to thermal treatment. However, when waste of electric and electronic equipment (WEEE) is the source of SR, thermal treatment is complicated by halogens as well as the presence of polybrominated dioxins and furans (PBDD/F) and brominated flame retardants (BFR). Hence, WEEE requires high temperature incineration with sufficient residence times. Post-combustion synthesis of polyhalogenated dioxins and furans (PXDD/F) is dominant in the temperature range between 250-450 degrees C. Thus, a very rapid gas cooling from 450 degrees to 250 degrees C is important for proper raw gas treatment. The pebble heater technology developed by ATZ Entwicklungszentrum (Sulzbach-Rosenberg, Germany) might serve as an alternative to the state-of-the-art quench cooling. It is based on the application of a pebble bed of natural bulk material, which the exhaust gases flows through radially. It provides an excellent heat transfer and a temperature gradient in the range of 1,500-2,000 K/m. The paper presents data of a pilot application of the pebble heater technology for the treatment of raw gas derived from the incineration of polymeric materials from WEEE. METHODS: A liquid fuel was chosen in order to minimise technical modifications of the plant. It was analysed for halogens by x-ray fluorescence, for brominated flame retardants by HPLC-UV/MS and for PXDD/F by GC-HRMS. Combustion gases were rapidly cooled down to temperatures below 200 degrees C and emissions of PBDD/F and PCDD/ F were estimated without further off-gas treatment. PBDD/F emissions were computed as PCDD/F toxicity equivalents applying two different calculation approaches. RESULTS AND DISCUSSION: PCDD/F emissions accounted for 0.04 ng I-TEQ/Nm3 and are in compliance with European emission limits. Calculated PBDD/F toxicity equivalents exceeded the emission limit of 0.1 ng I-TEQ/Nm3 by factors of 75 and 208 depending on the calculation approach. A mass balance of PBDD/F and PCDD/F congeners revealed an efficient elimination of more than 95% in most cases. Lower reduction rates (76% for 2,3,7,8-TeBDF and 82% for 1,2,3,7,8-PeBDF) were attributed to incomplete combustion. An intended recovery of halogens by one-stage scrubbing downstream of the pebble heater was ineffective, recovering 28% of the applied chlorine and 9% of the bromine, only. CONCLUSIONS: Our pilot incineration test indicates that the pebble heater technology can effectively suppress a post-combustion synthesis of PCDD/F and PBDD/F, resulting in low PCDD/F emission levels without further off-gas treatment. The presented data state that WEEE is sensible to incomplete combustion, which will lead to increased PBDD/F emissions without increasing PCDD/F emission limits. This finding is especially relevant for small and low-technical incineration appliances, which have been reported to treat WEEE in developing countries and are considered to serve as a significant source of PXDD/F these days. RECOMMENDATIONS AND PERSPECTIVES: Monitoring of PCDD/F emissions only might considerably underestimate the total emission of dioxins and dioxin-like compounds. It is therefore an ineffective means for assessing resulting health risks, at least for those waste treatment plants which are considered to handle the increasing amounts of PBDD/ F-containing polymers from WEEE in future. Consequently, it is recommended to initiate a screening programme for PXDD/F emissions in large scale incineration facilities which are capable of treating WEEE shredder residues.     

上海市废弃电器电子产品回收现状及分析

基于废弃电器电子产品产生量大、价值高、危害性强等特点,阐述了对它们进行回收处理的必然性。文中在调研上海市废弃电器电子产品回收量、预测其产生量的基础上,阐明了在家电以旧换新的政策下上海市废弃电器电子产品具有很高回收率以及废弃电视机的所占比例极高的特点,并分析了产生这种现象的原因。     

Evolutionary game analysis of WEEE recycling tripartite stakeholders under variable subsidies and processing fees

Environmental Science and Pollution Research - The standardization of formal recycling and rational subsidy plays an important role in waste electrical and electronic equipment recycling. In order...     

Factors influencing appropriate management of household hazardous waste in Nakhon Nayok,Thailand: A multilevel analysis

Household hazardous products contain hazardous chemicals, so when discarding these products a household hazardous waste (HHW) stream is created. HHW is a major environmental problem in Thailand, yet HHW has received scant attention so management is often inadequate or inappropriate. The objective of this study was to investigate the factors associated with appropriate HHW management in Thailand. Data were collected using a structured questionnaire completed during randomly assigned household interviews in Nakhon Nayok province, Thailand, between February and May 2017. The proportion of “appropriate management” was presented as percentage with its 95% confidence interval (CI). A multilevel mixed-effects logistic regression model was performed to determine the factors associated with appropriate HHW management, with 663 households included. The proportion of appropriate HHW management was 23.4% (95%CI: 20.2% to 26.6%). Both individual and local government administrative organization factors had on an effect on appropriate HHW management, including (a) being female (adjusted odds ratio [OR]:1.59; 95%CI: 1.03 to 2.46); (b) household size (adjusted OR: 1.66; 95%CI: 1.09 to 2.54); (c) knowledge score vis-à-vis HHW management (adjusted OR: 1.78; 95%CI: 1.43 to 2.02); (d) appropriate HHW storage behavior (adjusted OR: 2.48; 95%CI: 1.60 to 3.83); and (e) appropriate HHW use behavior (adjusted OR: 3.97; 95%CI: 2.40 to 6.58). The government of Thailand might consider a program to increase appropriate management of household hazardous waste to mitigate public health and environmental contamination risks.

Implications: Household hazardous waste becomes a major concern in many countries, including Thailand. The household hazardous waste management should be started at the source first, because household hazardous waste is mixed with the municipal waste stream. Thus, this study finding will be important for policymakers such as government and local government and can be used to create a specific policy and campaigns for household hazardous waste management.     

Influence factors of multicomponent mixtures containing reactive chemicals and their joint effects

Organic chemicals usually coexist as a mixture in the environment, and the mixture toxicity of organic chemicals has received increased attention. However, research regarding the joint effects of reactive chemicals is lacking. In this study, we examined two kinds of reactive chemicals, cyanogenic toxicants and aldehydes and determined their joint effects on Photobacterium phosphoreum. Three factors were found to influence the joint effects of multicomponent mixtures containing reactive chemicals, including the number of components, the dominating components and the toxic ratios. With an increased number of components, the synergistic or antagonistic effects (interactions) will weaken to the additive effects (non-interactions) if the added component cannot yield a much stronger joint effect with an existing component. Contrarily, the joint effect of the mixture may become stronger instead of weaker if the added components can yield a much stronger joint effect than the existing joint effect of the multicomponent mixture. The components that yield the strongest interactions in their binary mixture can be considered the dominating components. These components contribute more to the interactions of multicomponent mixtures than other components. Moreover, the toxic ratios also influence the joint effects of the mixtures. This study provides an insight into what are the main factors and how they influence the joint effects of multicomponent mixtures containing reactive chemicals, and thus, the findings are beneficial to the study of mixture toxicology.