基于火用参数环境影响评价探讨

基于煳参数与环境之间的关系，论述了将斓参数用于环境影响评价的可行性。提出通过修正标准参考环境而确定安全基准环境的理论，然后用足用参数来评价不同污染物的环境影响。阐述了火电厂系统、标准参考环境和安全基准环境三者之间的关系。     

Emergy analysis of the recycling options for construction and demolition waste

Construction and demolition (C&D) waste is becoming a major contributor to environmental pollution. In Shanghai, China, the quantity of C&D waste is 2.11E+07 t/yr, which accounts for 45% of the total quantity of solid waste. There has been a growing promotion of recycling C&D waste as an effective way to solve this waste problem. However, the evaluation of the efficiency of recycling C&D waste as a potential source of resources is largely based on traditional economic analysis. The economic analysis emphasizes money instead of the harmony between economic benefit and environmental effects. There is a need for a new strategic approach to investigate the efficiency of recycling C&D waste to achieve the integration between economic, social and environmental effects. Emergy theory can be employed to analyze different recycling options for C&D waste. With reference to the Chinese construction industry, this paper demonstrates that the close-loop recycling option is better than the open-loop recycling option for C&D waste in terms of the integration of social, environmental and sustainable aspects. To evaluate different technology solutions for C&D waste recycling, the emergy theory and method is not limited to a cost-benefit balance but can include economic, social, environmental and sustainable effects.     

Evaluation of recycling policies for PET bottles based on multiattribute utility indices

This study focused on waste plastic, especially the polyethylene telephthalate (PET) bottle as representative waste, which has been assigned as goods to be recycled by the Packaging Waste Recycling Law in Japan. We developed a plastic transport model which explained the entire flow of plastic from the production stage to the disposal stage within an the evaluation model of plastic recycle policy based on multiattribute utility theory. This model is designed to be used by local municipal governments in supporting the evaluation of the PET bottle recycling policy. In evaluating the plastics recycling policy, we selected indices relating to economy, ecology, and rate of resource recycling. The results indicate that when the evaluation of the material recycling policy and thermal recycling policy in the model city were characterized in terms of their economic and environmental aspects the thermal recycling policy had the highest utility within our scenario. Received: July 31, 1998 / Accepted: January 26, 1999     

Use of life cycle assessment as decision-support tool for water reuse and handling of residues at a Danish industrial laundry.

This analysis presents the results of a life cycle assessment (LCA) carried out on six alternative options for the recycling of water at a Danish industrial laundry for workwear. The study focuses on the handling and disposal of the wet residues generated when wastewater is treated for recycling, and in accounting for long-term potential toxicity impacts. The analysed options are a combination of two water-upgrading technologies: biofilter and ultrafiltration, and three residue disposal alternatives: biogas followed by incineration of sludge at local wastewater treatment plant, thermal vitrification treatment for production of vitrified sand, and mineralization in a sludge bed. It is concluded from the results that with the current Danish environmental policy priorities, the environmental impacts of highest priority are the toxicity effects derived from the presence of heavy metals in the residues. Heavy metals originate from the dirt in the workwear that is washed in the laundry. It is further concluded that the studied water treatment technologies satisfy both the need of clean water for recycling and simultaneously help controlling a safe disposal of pollutants by concentration of the residues. The results of the study also confirm the potential of LCA as a decision-support tool for assisting water recycling initiatives and for residue handling management. The handling of residues has been identified as a stage of the water recycling strategy that bears important environmental impacts. This holistic perspective provided by LCA can be used as input for the definition of environmental management strategies at an industrial laundry, and the prioritization of investments to the environmental profile of laundry processes. In this case-study, the results of the LCA are made operational by, for example, selecting the water treatment technology which is associated wih a safe disposal of the wet residue. It is important to bear in mind that such prioritization depends on national boundary conditions. In the case study analysed, the boundary conditions steer the weighing of the environmental impacts, following the current Danish environmental policy priorities.     

Mathematical modelling as a tool for environmental evaluation of industrial sectors in Colombia

A general mathematical model has been developed as a tool for environmental evaluation of industrial chemical processes. This model is based on the life cycle assessment (LCA) methodology and includes a modular and cumulative conceptual approximation. Accordingly, the model considers the potential effects on the environment caused by mass, energy and exergy flows. For environmental loads related with mass flows, two main categories are defined: pollution and perturbation environmental effects. Whereas for the environmental effect associated with energy flows, a factor defined as “energy dissipation” is employed, and similarly for exergy flows, a “exergy destruction” parameter is used. The measurement unit employed throughout the model is expressed in terms of “potential environmental impact units/hour”. As an example study case, the integrated production chain (IPC) for nitric acid production in the Colombian context is evaluated. This particular IPC includes the ammonia production plant, energy plants and main process plant. The results demonstrate that for environmental perturbation effects based on mass flows, the main contribution in the IPC corresponds to the energy plants. In the case of pollution environmental loads, the principal contribution relates to ammonia production. Regarding environmental effects associated with energy flows, the highest “energy dissipation” factor corresponds to the main process, followed in order by the ammonia process. Finally, for the effect denominated as “exergy destruction”, it could be established that Colombian energy plants show the highest contribution in the IPC.     

Informal electronic waste recycling: a sector review with special focus on China

Informal recycling is a new and expanding low cost recycling practice in managing Waste Electrical and Electronic Equipment (WEEE or e-waste). It occurs in many developing countries, including China, where current gaps in environmental management, high demand for second-hand electronic appliances and the norm of selling e-waste to individual collectors encourage the growth of a strong informal recycling sector. This paper gathers information on informal e-waste management, takes a look at its particular manifestations in China and identifies some of the main difficulties of the current Chinese approach. Informal e-waste recycling is not only associated with serious environmental and health impacts, but also the supply deficiency of formal recyclers and the safety problems of remanufactured electronic products. Experiences already show that simply prohibiting or competing with the informal collectors and informal recyclers is not an effective solution. New formal e-waste recycling systems should take existing informal sectors into account, and more policies need to be made to improve recycling rates, working conditions and the efficiency of involved informal players. A key issue for China’s e-waste management is how to set up incentives for informal recyclers so as to reduce improper recycling activities and to divert more e-waste flow into the formal recycling sector.     

Networking possibilities for waste recycling in Miyagi prefecture, Japan

Successful case studies for waste recycling in Japan have not been evaluated. The evaluation of economic efficiency and environmental effects were lacking at the time the actual network was established. A waste/resource input/output (I/O) coincidence retrieval system called ZENESYS was developed to examine the usefulness of a waste-exchange network in a nonmanufacturing district. We analyzed data from the Miyagi prefecture, a region without heavy industry. The data were collected from 77 companies using a questionnaire and interviews. A total of 33 possible waste exchange links arose after analysis using ZENESYS. However, these were frail networks that relied heavily on the construction industry. Two waste recycling technologies were selected from the ZENESYS database: reclaiming fuel from waste plastic and making construction materials from bottom ash. Evaluation of the environmental effects and economics of these two technologies showed they were both suitable for the environment, but no profit was made from reclaiming fuel from waste plastics. We concluded that in an area with no heavy industry, it may be difficult to adopt recycling technologies that have high environmental and economic performance. Materials are difficult to circulate among manufacturing industries even if a waste-exchange network exists, and resources are consumed during transportation and recycling.     

Chemical Recycling of PLA: A Great Opportunity Towards the Sustainable Development?

This work aims at analyzing the energy efficiency of the chemical recycling process of polylactic acid (PLA) and its sustainability from an environmental point of view. The results show that the production of lactic acid from chemical depolymerization of PLA is preferable, from an energy point of view, to the production of lactic acid by glucose fermentation. The study also shows that the environmental footprint of the analyzed process is larger than that of the PLA mechanical recycling.     

An international comparative study of end-of-life vehicle (ELV) recycling systems

End-of-life vehicles (ELV) have become a global concern as automobiles have become popular worldwide. An international workshop was held to gather data and to discuss 3R policies and ELV recycling systems, their background and present situation, outcomes of related policies and programs, the framework of recycling and waste management, and case studies on related topics in several countries and regions, as well as the essential points of the comparison. Legislative ELV recycling systems are established in the EU, Japan, Korea, and China, while in the US, ELV recycling is managed under existing laws on environmental protection. Since automobile shredding residue (ASR) has a high calorific value and ash content, and includes heavy metals as well as a mass of unclassified fine particles, recycling ASR is considered highly difficult. Countries with a legislative ELV system commonly set a target for recovery rates, with many aiming for more than 95 % recovery. In order to reach this target, higher efficiency in ASR recovery is needed, in addition to material recycling of collectable components and metals. Environmentally friendly design was considered necessary at the planning and manufacturing stages, and the development of recycling systems and techniques in line with these changes are required for sound ELV management.     

Application of system dynamics modeling for evaluation of different recycling scenarios in Singapore

The influence of socioeconomic factors, such as population and rapid economic growth, and the change of consumption and living patterns make waste management in Singapore, a complex issue. Due to limited land and resources, the solid waste management scheme requires a comprehensive approach. Therefore, system dynamics (SD) modeling was applied to assess alternative strategies for solid waste management by interconnecting landfill capacity and recycling efficiency with reference to the projection on waste generation. Nine different scenarios were investigated to identify the best approach to maintain environmental sustainability without inhibiting the economic growth. Four subsystems (i.e., population, economy, waste recycling, and waste disposal) have been incorporated into the SD model to broaden the effectiveness of the waste management system. Research findings revealed that a high economic pattern and a high recycling rate are recommended to satisfy the requirements for economic growth and environmental sustainability while extending landfill capacity for waste disposal. Even though the balance of expenditure could be increased by the high recycling rate, it meets the need for long-term incineration and landfill planning.     

Life cycle assessment of integrated recycling schemes for plastic containers and packaging with consideration of resin composition

Many life cycle assessment studies have evaluated and compared the environmental performance of various technologies for recycling plastic containers and packaging in Japan and other countries. However, no studies have evaluated the combination of recycling technologies in consideration of the resin composition in terms of the quantity of each recycled product so as to maximize their environmental potential. In this study, 27 scenarios of recycling schemes for household waste plastic containers and packaging are developed through integrating a conventional recycling scheme with additional recycling schemes. The conventional recycling scheme involves municipal curbside collection and either the material recycling or feedstock recycling of waste plastics. The additional recycling schemes are feedstock recycling in steel works of the residue from conventional material recycling processes, and corporate voluntary collection and independent material recycling of specific types of plastic trays. Life cycle assessment based on the modeling of recycling processes considering the resin composition in terms of the quantity of each recycled product is applied to evaluate and compare these scenarios from the viewpoints of fossil resource consumption and CO₂ emission. The results show that the environmental loads are reduced in all scenarios including the additional recycling schemes compared with the conventional recycling scheme. However, the independent plastic tray recycling scheme exhibits lower additional environmental savings when the residue recycling scheme is integrated with the conventional material recycling scheme. This is because both additional recycling schemes aim to utilize polystyrene and polyethylene terephthalate, which would otherwise be incinerated as residue from material recycling processes. The evaluation of the environmental loads of plastic recycling with consideration of the resin composition in terms of the quantity of each recycled product makes it possible to investigate recycling schemes that integrate different technologies to maximize their environmental potential.     

Comparisons of four categories of waste recycling in China's paper industry based on physical input-output life-cycle assessment model

Waste recycling for paper production is an important component of waste management. This study constructs a physical input-output life-cycle assessment (PIO-LCA) model. The PIO-LCA model is used to investigate environmental impacts of four categories of waste recycling in China’s paper industry: crop straws, bagasse, textile wastes and scrap paper. Crop straw recycling and wood utilization for paper production have small total intensity of environmental impacts. Moreover, environmental impacts reduction of crop straw recycling and wood utilization benefits the most from technology development. Thus, using crop straws and wood (including wood wastes) for paper production should be promoted. Technology development has small effects on environmental impacts reduction of bagasse recycling, textile waste recycling and scrap paper recycling. In addition, bagasse recycling and textile waste recycling have big total intensity of environmental impacts. Thus, the development of bagasse recycling and textile waste recycling should be properly limited. Other pathways for reusing bagasse and textile wastes should be explored and evaluated. Moreover, imports of scrap paper should be encouraged to reduce large indirect impacts of scrap paper recycling on domestic environment.     

The development and prospects of the end-of-life vehicle recycling system in Taiwan

Automobiles usually contain toxic substances, such as lubricants, acid solutions and coolants. Therefore, inappropriate handling of end-of-life vehicles (ELVs) will result in environmental pollution. ELV parts, which include metallic and non-metallic substances, are increasingly gaining recycling value due to the recent global shortage of raw materials. Hence, the establishment of a proper recycling system for ELVs will not only reduce the impact on the environment during the recycling process, but it will also facilitate the effective reuse of recycled resources. Prior to 1994, the recycling of ELVs in Taiwan was performed by related operators in the industry. Since the publishing of the “End-of-life vehicle recycling guidelines” under the authority of the Waste Disposal Act by the Environmental Protection Administration (EPA) in 1994, the recycling of ELVs in Taiwan has gradually become systematic. Subsequently, the Recycling Fund Management Board (RFMB) of the EPA was established in 1998 to collect a Collection–Disposal–Treatment Fee (recycling fee) from responsible enterprises for recycling and related tasks. Since then, the recycling channels, processing equipment, and techniques for ELVs in Taiwan have gradually become established. This paper reviews the establishment of the ELV recycling system, analyzes the current system and its performance, and provides some recommendations for future development. The reduction of auto shredder residue (ASR) is a key factor in maximizing the resource recovery rate and recycling efficiency. The RFMB needs to provide strong economic incentives to further increase the recycling rate and to encourage the automobile industry to design and market greener cars.     

Recycling of WEEE plastics: a review

Electric and electronic equipment (EEE) is swiftly growing in volume, level of sophistication, and diversity. Also, it evolves briskly, moved by innovation and technical change, and draws on numerous and at times rare resources. Waste EEE (WEEE) has evolved into an important societal problem. Recycling and treating WEEE implies occupational as well as environmental hazards that are still incompletely documented. Still, second hand EEE has been exported and treated in Africa, China, and India in a precarious informal context. In developed countries, EEE recycling has been sustained by a wide range of initiatives and motives, such as sustainability, creating jobs, and the value of precious or rare metals. Current EU Directives require a steep reduction of WEEE plastics (WEEP) going to landfill. Mechanical, thermal, and feedstock recycling of WEEP are analysed and some options confronted. Plastics recycling should be weighed against the eventual risks related to their hazardous ingredients, mainly legacy brominated fire retardants and heavy metals. Another paper is related to a somewhat similar problem, yet involving a different mix of plastics: recycling plastics from automotive shredder residue.     

Enhancement of the recycling of waste Ni-Cd and Ni-MH batteries by mechanical treatment

A serious environmental problem was presented by waste batteries resulting from lack of relevant regulations and effective recycling technologies in China. The present work considered the enhancement of waste Ni-Cd and Ni-MH batteries recycling by mechanical treatment. In the process of characterization, two types of waste batteries (Ni-Cd and Ni-MH batteries) were selected and their components were characterized in relation to their elemental chemical compositions. In the process of mechanical separation and recycling, waste Ni-Cd and Ni-MH batteries were processed by a recycling technology without a negative impact on the environment. The technology contained mechanical crushing, size classification, gravity separation, and magnetic separation. The results obtained demonstrated that: (1) Mechanical crushing was an effective process to strip the metallic parts from separators and pastes. High liberation efficiency of the metallic parts from separators and pastes was attained in the crushing process until the fractions reached particle sizes smaller than 2 mm. (2) The classified materials mainly consisted of the fractions with the size of particles between 0.5 and 2 mm after size classification. (3) The metallic concentrates of the samples were improved from around 75% to 90% by gravity separation. More than 90% of the metallic materials were separated into heavy fractions when the particle sizes were larger than 0.5 mm. (4) The size of particles between 0.5 and 2 mm and the rotational speed of the separator between 30 and 60 rpm were suitable for magnetic separation during industrial application, with the recycling efficiency exceeding 95%.     

Assessing recycling versus incineration of key materials in municipal waste: The importance of efficient energy recovery and transport distances

Recycling of materials from municipal solid waste is commonly considered to be superior to any other waste treatment alternative. For the material fractions with a significant energy content this might not be the case if the treatment alternative is a waste-to-energy plant with high energy recovery rates. The environmental impacts from recycling and from incineration of six material fractions in household waste have been compared through life cycle assessment assuming high-performance technologies for material recycling as well as for waste incineration. The results showed that there are environmental benefits when recycling paper, glass, steel and aluminium instead of incinerating it. For cardboard and plastic the results were more unclear, depending on the level of energy recovery at the incineration plant, the system boundaries chosen and which impact category was in focus. Further, the environmental impact potentials from collection, pre-treatment and transport was compared to the environmental benefit from recycling and this showed that with the right means of transport, recyclables can in most cases be transported long distances. However, the results also showed that recycling of some of the material fractions can only contribute marginally in improving the overall waste management system taking into consideration their limited content in average Danish household waste.     

Evaluation of the effect of automotive bumper recycling by life-cycle inventory analysis

This paper describes a case study of the application of life-cycle inventory analysis to automotive bumper recycling. Two scenarios of bumper recycling are compared. One is “bumper-to-bumper recycling,” in which we recycle bumpers into more bumpers. The other is “cascade recycling,” in which bumpers are recycled into different parts of a car with a lower function. Inventory analysis is applied to both these recycling scenarios by analyzing the stages of acquiring natural resources, manufacturing materials, and parts, disposal, and recycling. We chose air emission, solid waste, and fossil fuel resources as items of the inventory analysis. We quantified the effect of reductions in the environmental load by recycling bumpers, and found that reductions in the environmental load were larger with cascade recycling than with bumper-to-bumper recycling based on current conditions. Received: February 2, 2000 / Accepted: April 21, 2000     

Improving the layout of recycling centres by use of lean production principles

There has been increased focus on recycling in Sweden during recent years. This focus can be attributed to external environmental factors such as tougher legislation, but also to the potential gains for raw materials suppliers. Recycling centres are important components in the Swedish total recycling system. Recycling centres are manned facilities for waste collection where visitors can bring, sort and discard worn products as well as large-sized, hazardous, and electrical waste. The aim of this paper was to identify and describe the main flows and layout types at Swedish recycling centres. The aim was also to adapt and apply production theory for designing and managing recycling centre operations. More specifically, this means using lean production principles to help develop guidelines for recycling centre design and efficient control.Empirical data for this research was primarily collected through interviews and questionnaires among both visitors and employees at 16 Swedish recycling centres. Furthermore, adapted observation protocols have been used in order to explore visitor activities. There was also close collaboration with a local recycling centre company, which shared their layout experiences with the researchers in this project.The recycling centres studied had a variety of problems such as queues of visitors, overloading of material and improper sorting. The study shows that in order to decrease the problems, the recycling centres should be designed and managed according to lean production principles, i.e. through choosing more suitable layout choices with visible and linear flows, providing better visitor information, and providing suitable technical equipment. Improvements can be achieved through proper planning of the layout and control of the flow of vehicles, with the result of increased efficiency and capacity, shorter visits, and cleaner waste fractions. The benefits of a lean production mindset include increased visitor capacity, waste flexibility, improved sorting quality, shorter time for visits and improved working conditions.     

Removal of polychlorinated biphenyls from capacitors and pressure-sensitive paper by vacuum thermal recycling

This paper describes a new vacuum thermal recycling (VTR) method for treating discarded polychlorinated biphenyls (PCB)-contaminated capacitors and pressure-sensitive paper. Based on results demonstrating an exceptionally high PCB separation efficiency and recovery ratio from capacitors containing high-concentration PCBs, i.e. > 99.9%, respectively, the presented VTR method is verified to effectively remove PCBs. In addition, associated safety aspects of the employed procedure were confirmed.     

An overview on the processes and technologies for recycling cathodic active materials from spent lithium-ion batteries

This paper aims to make an overview on the current status and new tendency for recycling cathodic active materials from spent lithium-ion batteries. Firstly, it introduces several kinds of pretreatment technologies, followed by the summary of all kinds of single recycling processes mainly focusing on organic acid leaching and synergistic extraction. Then, several examples of typical combined processes and industrial recycling processes are presented in detail. Meanwhile, the advantages, disadvantages and prospect of each single process, combined process, as well as industrial recycling processes, are discussed. Finally, based on a novel acidic organic solvent, the authors briefly introduce an environmental friendly process to directly recycle and resynthesize cathodic active material LiNi_1/3Co_1/3Mn_1/3O₂ from spent lithium-ion batteries. The preliminary experimental results demonstrated the advantages of low reaction temperature, high separation efficiency and organic solvent cycling and preventing secondary pollution to the environment. This process may be used for large-scale recycling of spent lithium-ion batteries after further study.