Air emissions from pavement layers composed of varying rates of reclaimed asphalt

An experimental study of road building and recycling of used pavement has been conducted within the framework of a Life Cycle Analysis. Four equivalent asphalt concretes made with different recycling rates have been investigated during road construction. Airborne emissions, pollutant release over time and odor production related to asphalt laying have all been determined and compared among the various recycling rates. All of the results (VOC, PAH and odors), expressed in terms of concentrations and fluxes, exhibit quite monotonic variations with respect to the recycling rate. These results, however, did not reveal the same trend as a function of the recycling rate (increases or decreases), depending on the selected target parameter (VOC or PAH). Indicators have been proposed for a discussion of results that take into account: (i) raw material emissions with respect to the reference defined in the case of pavement without reclaimed asphalt; and (ii) emissions in each case from all material production sources.     

A model recycling program for Alabama

Solid waste disposal is becoming a difficult problem for many states. Since 1960, the amount of municipal solid waste (MSW) has been increasing at a rate of 1% per year. More than 75% of the waste is comprised of recyclable materials. Several states have mandated recycling to decrease the volume of waste intended for disposal. Those mandated programs are very popular, but depend on many political, social, and economic factors for success. While Alabama has the manufacturing infrastructure to support a mandated recycling program, no recycling legislation has been promulgated. At this time recycling is only being done on a voluntary basis. A mandatory program with the proper support, education and funding could allow Alabama to recycle much of the 5.2 million tons of waste that are generated within its borders each year.     

Current results and future perspectives for Japanese recycling of home electrical appliances

The Japanese system of recycling home electrical appliances has several unique aspects, including (1) a limited number of target appliances, (2) a recycling fee system that requires consumers to pay a recycling fee at the time of disposal, and (3) a direct recycling obligation for manufacturers, who have a physical, rather than a financial, responsibility for their end-of-life products. We studied data from 2001 to 2007 and found that the amount of four specified home electrical appliances and their materials that was recycled increased from about 319,249 tonnes in 2001 to about 447,262 tonnes—or 3.5 kg per inhabitant—in 2006. Recycling yield and development of recycling technologies have also improved. New recycling technologies have enabled a higher rate of material recycling of plastics (i.e., a closed-loop recycling). Improved eco-design, such as design for easier disassembly, has been promoted, and the higher quality of discarded appliances has enhanced the reuse market. Hazardous substances and fluorocarbons are being well managed. Problems with the recycling system include inelastic recycling fees, illegal dumping, illegal transfer by retailers, and the limited number of target appliances. Recycling fees could be reduced; this move might reduce the incidence of illegal dumping, as would engage stakeholders in collaborative efforts against illegal dumping. Illegal transfers could be reduced by improved traceability for retailers. Products such as liquid crystal displays, plasma display panels and clothes dryers have become increasingly common and should be also be targeted for recycling.     

Current results and future perspectives for Japanese recycling of home electrical appliances

The Japanese system of recycling home electrical appliances has several unique aspects, including (1) a limited number of target appliances, (2) a recycling fee system that requires consumers to pay a recycling fee at the time of disposal, and (3) a direct recycling obligation for manufacturers, who have a physical, rather than a financial, responsibility for their end-of-life products. We studied data from 2001 to 2007 and found that the amount of four specified home electrical appliances and their materials that was recycled increased from about 319,249 tonnes in 2001 to about 447,262 tonnes—or 3.5 kg per inhabitant—in 2006. Recycling yield and development of recycling technologies have also improved. New recycling technologies have enabled a higher rate of material recycling of plastics (i.e., a closed-loop recycling). Improved eco-design, such as design for easier disassembly, has been promoted, and the higher quality of discarded appliances has enhanced the reuse market. Hazardous substances and fluorocarbons are being well managed. Problems with the recycling system include inelastic recycling fees, illegal dumping, illegal transfer by retailers, and the limited number of target appliances. Recycling fees could be reduced; this move might reduce the incidence of illegal dumping, as would engage stakeholders in collaborative efforts against illegal dumping. Illegal transfers could be reduced by improved traceability for retailers. Products such as liquid crystal displays, plasma display panels and clothes dryers have become increasingly common and should be also be targeted for recycling.     

The time-varying factors influencing the recycling rate of products

In Europe targets have been laid down by EU legislation for the recycling rate of end-of-life vehicles to be achieved within the nearby future. It is illustrated in this paper that the definition of the recycling rate and the realisation of the imposed targets are very much dependent on different parameters such as the changing lifetime of the product and product design. It may seem obvious that the recycling rate is determined by various time-varying factors, however, this paper endeavours to describe and quantify the role of these factors on the recycling rate over time by the use of a dynamic systems model. This model permits the prediction of the recycling rate as a function of the numerous presented parameters, changing design scenarios etc. In addition, different definitions of the recycling rate will be presented and discussed. This will lead to a better understanding of the parameters affecting the recycling system and a more precise understanding of the recycling targets and their realisation as imposed by EU legislation. This paper focuses on cars, but the discussion and the definitions derived are equally valid for any end-of-life product.     

Recycling and the Environmental Debate: A Question of Social Conscience or Scientific Reason?

Social conscience and public opinion have promoted a popular belief that all recycling is good for the environment. Planning policies and environmental legislation have been and continue to be influenced in part by this belief. Economic and political factors have been important especially in terms of developing recovery programmes and systems for collecting waste material. This is particularly true for paper products, for which there is now a whole range of arbitrary set recycling targets in most western countries. Paper products are different from all other major recycled products in that they are made from a renewable resource and, as recovered waste, it has alternative uses such as energy recovery. In the framework of mounting empirical evidence the aim of the paper is to question the validity of social conscience as a raison d'etre for increasing the rate of recycling paper products. Forests, which are the primary renewable resource, have important implications for a whole range of economic, social and climatic issues, especially global warming. There is an urgent need to take stock of these issues for both planning and managing the environment.     

Life cycle assessment of waste paper management: The importance of technology data and system boundaries in assessing recycling and incineration

The significance of technical data, as well as the significance of system boundary choices, when modelling the environmental impact from recycling and incineration of waste paper has been studied by a life cycle assessment focusing on global warming potentials. The consequence of choosing a specific set of data for the reprocessing technology, the virgin paper manufacturing technology and the incineration technology, as well as the importance of the recycling rate was studied. Furthermore, the system was expanded to include forestry and to include fossil fuel energy substitution from saved biomass, in order to study the importance of the system boundary choices. For recycling, the choice of virgin paper manufacturing data is most important, but the results show that also the impacts from the reprocessing technologies fluctuate greatly. For the overall results the choice of the technology data is of importance when comparing recycling including virgin paper substitution with incineration including energy substitution. Combining an environmentally high or low performing recycling technology with an environmentally high or low performing incineration technology can give quite different results. The modelling showed that recycling of paper, from a life cycle point of view, is environmentally equal or better than incineration with energy recovery only when the recycling technology is at a high environmental performance level. However, the modelling also showed that expanding the system to include substitution of fossil fuel energy by production of energy from the saved biomass associated with recycling will give a completely different result. In this case recycling is always more beneficial than incineration, thus increased recycling is desirable. Expanding the system to include forestry was shown to have a minor effect on the results. As assessments are often performed with a set choice of data and a set recycling rate, it is questionable how useful the results from this kind of LCA are for a policy maker. The high significance of the system boundary choices stresses the importance of scientific discussion on how to best address system analysis of recycling, for paper and other recyclable materials.     

Life cycle assessment of waste paper management: The importance of technology data and system boundaries in assessing recycling and incineration

The significance of technical data, as well as the significance of system boundary choices, when modelling the environmental impact from recycling and incineration of waste paper has been studied by a life cycle assessment focusing on global warming potentials. The consequence of choosing a specific set of data for the reprocessing technology, the virgin paper manufacturing technology and the incineration technology, as well as the importance of the recycling rate was studied. Furthermore, the system was expanded to include forestry and to include fossil fuel energy substitution from saved biomass, in order to study the importance of the system boundary choices. For recycling, the choice of virgin paper manufacturing data is most important, but the results show that also the impacts from the reprocessing technologies fluctuate greatly. For the overall results the choice of the technology data is of importance when comparing recycling including virgin paper substitution with incineration including energy substitution. Combining an environmentally high or low performing recycling technology with an environmentally high or low performing incineration technology can give quite different results. The modelling showed that recycling of paper, from a life cycle point of view, is environmentally equal or better than incineration with energy recovery only when the recycling technology is at a high environmental performance level. However, the modelling also showed that expanding the system to include substitution of fossil fuel energy by production of energy from the saved biomass associated with recycling will give a completely different result. In this case recycling is always more beneficial than incineration, thus increased recycling is desirable. Expanding the system to include forestry was shown to have a minor effect on the results. As assessments are often performed with a set choice of data and a set recycling rate, it is questionable how useful the results from this kind of LCA are for a policy maker. The high significance of the system boundary choices stresses the importance of scientific discussion on how to best address system analysis of recycling, for paper and other recyclable materials.     

废印刷线路板处置和非金属回收利用研究进展

废印刷线路板的资源化处置一直是电子废弃物处理的热点和难点,目前有多种方法已经投入应用或者在研究阶段,这些方法在分离效率、回收率、操作简单性、本身环境友好性、有无二次污染等方面有不同的优缺点。目前主流的广泛采用的方法是分步处理,破碎后利用物理方法进行分选,得到的金属和非金属组分再分别进行进一步的回收利用。本文对近年来废印刷线路板的总体处置技术和物理分选后非金属的回收利用的研究进行了总结,并对将来的研究方向进行了展望,为废印刷线路板资源化再利用产业化发展提供参考。     

Modelling and analysis of international recycling between developed and developing countries

To deal with the complexity of recycling, a wide variety of models have been developed, each serving a specific purpose. Despite the current trend increasing international trade in recycling-related material flows, the international dimension of physical and economic relationships in recycling is often ignored in current models and analyses. This paper develops a formal model of an international material-product chain (MPC) that represents the mechanism behind international recycling. The attention is focused on the case of a developed and a developing country that exchange material commodities, final products and recyclable waste. Among others, the model demonstrates that taking into account environmental externalities results in higher levels of recycling. Moreover, we show that international recycling is mainly driven by regional differences in the quantity and quality of factor endowments and economic efficiency of recycling. Given that industrialised countries are relatively well endowed with recyclable waste, the recovery rate usually exceeds the utilisation rate. In developing countries, an opposite pattern is observed.     

Amounts of non-fibrous components in recovered paper

Paper and board recycling is now a central issue in papermaking. Understanding of material flows, as a part of the total production chain, as well as, fibrous and non-fibrous component flows needs further clarification. These flows are studied at a European level, with special focus on Germany and Sweden. Non-fibrous components are discussed in terms of a material which hampers the processing of paper and board. Resource-efficiency improvements, in conjunction with economic benefits, are sought and recycling has been able to fulfil both of these. The main drivers to maximize the use of recovered paper in paper and board manufacturing, have been improved over the last decades. These drivers are cost, environmental image and good technical properties to be used as raw material.The increased recycling rate has reduced the quality of the collected paper, produced recycled paper, and replaced virgin pulp. Also, recycling as a process, like deinking, produces large amounts of waste material that has challenges to find proper utilization. These problem areas are addressed in this paper, too.One focus area in the analysis of statistical information is an estimation of the share of non-fibrous components and fibre volumes of paper in Europe (EU) for the year 2010.     

Evaluation of recycling efforts of aircraft companies in Wichita

The number of manufactured aircraft has been continuously increasing worldwide because of the high demand for airline transportation. During manufacturing, many advanced materials and devices are used to build various sizes and shapes of aircraft. However, most of these materials and devices require considerable energy and labor to produce, so reusing these at any life stage of the aircraft offers many economic and environmental benefits, and is considered lucrative and environmentally responsible. Several recyclable materials—composites, metals and alloys, wires, wood, paper, plastics, electronics, and avionics—emerge as waste streams during the manufacturing of aircraft. Many aircraft companies have been recycling these materials to remanufacture aircraft parts or other products for more sustainable production. In the present study, we evaluated the recycling efforts of local aircraft companies in Wichita, KS. These efforts were considered in terms of recycling efficiency/rate and environmental benefits. These included cradle-to-gate (CTG) life-cycle inventory analysis of the materials, carbon dioxide emissions, virgin material replacement with recycled materials, and natural resources usage. Our findings show that there exists a significant potential for contributions to sustainability as well as environmental and health benefits in the region from recycling by aircraft manufacturing plants.     

The role of perceived effectiveness of policy measures in predicting recycling behaviour in Hong Kong

Hong Kong is a compact and ‘land-hungry’ city where recycling has become an important measure for treating waste and reducing the demand on the limited landfills. The objectives of this paper are to extend the model of recycling attitude and behaviour to explain the relationship between perceived policy effectiveness and recycling behaviour. Previous studies on recycling attitude and behaviour had widely adopted the theory of planned behaviour (TPB) and the norm activation model (NAM), and drawn policy implications from them. Nevertheless, little research has been conducted to investigate the role of perceived effectiveness of policy measures in predicting recycling behaviour. To address this, a model that integrates the TPB and NAM was proposed in this study, and a street survey was conducted to investigate the case. The results illustrate that recycling intention is influenced by subjective norms, perceived behavioural control, moral norms, and awareness of consequences, as well as a newly proposed construct, namely perceived policy effectiveness. The study proved self-reported recycling behaviour (direct behaviour) and support for policy measures (indirect behaviour) are influenced by recycling intention. All in all the Government should provide more recycling bins, guidelines on recycling activities, and should accent what it has been doing to facilitate and encourage recycling.     

Solid waste management in urban areas: Development and application of a decision support system

A decision support system (DSS) developed to assist the planner in decisions concerning the overall management of solid waste at a municipal scale is described. The DSS allows to plan the optimal number of landfills and treatment plants, and to determine the optimal quantities and the characteristics of the refuse that has to be sent to treatment plants, to landfills and to recycling. The application of the DSS is based on the solution of a constrained non-linear optimization problem. Various classes of constraints have been introduced in the problem formulation, taking into account the regulations about the minimum requirements for recycling, incineration process requirements, sanitary landfill conservation, and mass balance. The cost function to be minimized includes recycling, transportation and maintenance costs. The DSS has been tested on the municipality of Genova, Italy, and the results obtained are presented.     

Management and recycling of waste glass in concrete products: Current situations in Hong Kong

Disposal of more than 300 tonnes waste glass daily derived from post-consumer beverage bottles is one of the major environmental challenges for Hong Kong, and this challenge continues to escalate as limited recycling channels can be identified and the capacity of valuable landfill space is going to be saturated at an alarming rate. For this reason, in the past ten years, a major research effort has been carried out at The Hong Kong Polytechnic University to find practical ways to recycle waste glass for the production of different concrete products such as concrete blocks, self-compacting concrete and architectural mortar. Some of these specialty glass-concrete products have been successfully commercialized and are gaining wider acceptance. This paper gives an overview of the current management and recycling situation of waste glass and the experience of using recycled waste glass in concrete products in Hong Kong.     

Electronic labelling in recycling of manufactured articles

The concept of a recycling system aiming at the recovery of resources from manufactured articles is proposed. The system integrates electronic labels for product identification and internet for global data exchange. A prototype for the recycling of electric motors has been developed, which implements a condition-based recycling decision system to automatically select the environmentally and economically appropriate recycling strategy, thereby opening a potential market for second-hand motors and creating a profitable recycling process itself. The project has been designed to evaluate the feasibility of electronic identification applied on a large number of motors and to validate the system in real field conditions.     

我国再生资源行业现状分析及其发展趋势

再生资源回收利用的种类与数量的多少、回收率的高低,科学技术是决定因素之一。我国虽然从50年代初期就开始了有计划、全面系统的回收利用再生资源,对经济和衽会的发展起到了一定的促进作用。但是,同工业发达国家相比,回收的数量和利用水平还有很大差距。其关键就是我们的科学技术水平较低。因此,作者认为,要提高我国再生资源的利用水平,首先要重视这个行业的技术改造和科学研究。     

基于典型相关分析的电子类生活垃圾回收政策及其效果关系研究

本文围绕以手机为主的电子类生活垃圾回收环节,基于EPR电子生活垃圾回收实验及目前电子类生活垃圾的回收激励政策和效果,运用典型相关分析方法确定激励政策及政策效果的主要影响变量,研究以手机为主的电子类生活垃圾回收的激励政策与政策效果之间的关系,强化电子类生活垃圾回收的政策措施,扩大政策效果,促进资源的回收及再利用。本文设定的回收激励政策包括政府对废旧手机回收率的最低要求、优惠力度以及获得高优惠的最低回收率要求,政策效果包括废旧手机实际回收率、销售市场营业额以及生产者补贴总额等方面。研究结果表明,电子类生活垃圾回收激励政策与政策效果之间存在着显著的相关关系,其中,获得高优惠的最低回收率对废旧手机实际回收率有显著抑制作用,废旧手机回收率的最低要求对销售市场营业额有显著抑制作用。本文在此基础上给出了政策建议。     

A rationale for recycling

The decision as to whether to recycle discarded objects or not has traditionally been made on a simple financial basis. However, over the last few years a popular movement has sprung up which regards recycling as a good in itself, and this movement finds itself at odds with the present financial basis for recycling. In this paper a rationale for recycling is worked out in an attempt to resolve this conflict. It is concluded that the normal market signals do not provide a proper basis for recycling decisions and that this market failure must be corrected by government intervention. However, this intervention should not take the form of uncritical support for recycling. Rather the societal objectives of individual recycling proposals should be identified and the proposal should then be evaluated in terms of whether it would achieve these objectives more effectively than some alternative action.     

Differentiation of determinants of low-cost and high-cost recycling

The bulk of research on recycling has been devoted to disentangling factors that affect it. Based on the low-cost hypothesis, we suggest that psychological factors differentially influence behaviors that are relatively less costly to perform compared to behaviors that are more costly to perform. Recycling has often been viewed as low-cost behavior, neglecting that recycling in different waste categories may vary in cost. The aim of the present study was to apply and extend the low-cost hypothesis by investigating whether beliefs about environmental consequences, knowledge, and norms differentially affect low-cost and high-cost recycling. A survey of 418 participants showed that knowledge, social norms, and personal norms were related to both low-cost and high-cost recycling, but the relation was significantly stronger for high-cost recycling. Personal norms partially mediated procedural knowledge and social norms in both low-cost and high-cost recycling. The findings emphasize the need to regard recycling as a multiform behavior and to analyse its determinants separately for different waste categories.