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1.
The present article examines flows and stocks of Stockholm Convention regulated pollutants, commercial penta‐ and octabrominated diphenyl ether (cPentaBDE, cOctaBDE), on a city level. The goals are to (1) identify sources, pathways, and sinks of these compounds in the city of Vienna, (2) determine the fractions that reach final sinks, and (3) develop recommendations for waste management to ensure their minimum recycling and maximum transfer to appropriate final sinks. By means of substance flow analysis (SFA) and scenario analysis, it was found that the key flows of cPentaBDE stem from construction materials. Therefore, end‐of‐life (EOL) plastic materials used for construction must be separated and properly treated, for example, in a state‐of‐the‐art municipal solid waste (MSW) incinerator. In the case of cOctaBDE, the main flows are waste electrical and electronic equipment (WEEE) and, possibly, vehicles. Most EOL vehicles are exported from Vienna and pose a continental, rather than a local, problem. According to the modeling, approximately 73% of cOctaBDE reached the final sink MSW incinerator, and 17% returned back to consumption by recycling. Secondary plastics, made from WEEE, may thus contain significant amounts of cOctaBDE; however, uncertainties are high. According to uncertainty analysis, the major cause is the lack of reliable values regarding cOctaBDE concentrations in European WEEE categories 3 and 4, including cathode ray tube monitors for computers and televisions. We recommend establishing a new, goal‐oriented data set by additional analyses of waste constituents and plastic recycling samples, as well as establishing reliable mass balances of polybrominated diphenyl ethers’ flows and stocks by means of SFA.  相似文献   

2.
The diversity of raw materials used in modern products, compounded by the risk of supply disruptions—due to uneven geological distribution of resources, along with socioeconomic factors like production concentration and political (in)stability of raw material producing countries—has drawn attention to the subject of raw material “criticality.” In this article, we review the state of the art regarding the integration of criticality assessment, herein termed “product‐level supply risk assessment,” as a complement to environmental life cycle assessment. We describe and compare three methods explicitly developed for this purpose—Geopolitical Supply Risk (GeoPolRisk), Economic Scarcity Potential (ESP), and the Integrated Method to Assess Resource Efficiency (ESSENZ)—based on a set of criteria including considerations of data sources, uncertainties, and other contentious methodological aspects. We test the methods on a case study of a European‐manufactured electric vehicle, and conclude with guidance for appropriate application and interpretation, along with opportunities for further methodological development. Although the GeoPolRisk, ESP, and ESSENZ methods have several limitations, they can be useful for preliminary assessments of the potential impacts of raw material supply risks on a product system (i.e., “outside‐in” impacts) alongside the impacts of a product system on the environment (i.e., “inside‐out” impacts). Care is needed to not overlook critical raw materials used in small amounts but nonetheless important to product functionality. Further methodological development could address regional and firm‐level supply risks, multiple supply‐chain stages, and material recycling, while improving coverage of supply risk characterization factors.  相似文献   

3.
Carbon recycling, in which organic waste is recycled into chemical feedstock for material production, may provide benefits in resource efficiency and a more cyclical economy—but may also create “trade‐offs” in increased impacts elsewhere. We investigate the system‐wide environmental burdens and cost associated with carbon recycling routes capable of converting municipal solid waste (MSW) by gasification and Fischer‐Tropsch synthesis into ethylene. Results are compared to business‐as‐usual (BAU) cases in which ethylene is derived from fossil resources and waste is either landfilled with methane and energy recovery (BAU#1) or incinerated (BAU#2) with energy recovery. Monte Carlo and sensitivity analysis is used to assess uncertainties of the results. Results indicate that carbon recycling may lead to a reduction in cumulative energy demand (CED), total material requirement (TMR), and acidification, when compared to BAU#1. Global warming potential is found to be similar or slightly lower than BAU#1 and BAU#2. In comparison to BAU#2, carbon recycling results in higher CED, TMR, acidification, and smog potential, mainly as a result of larger (fossil‐based) energy offsets from energy recovery. However, if a renewable power mix (envisioned for the future) is assumed to be offset, BAU#2 impacts may be similar or higher than carbon recycling routes. Production cost per kilogram (kg) MSW‐derived ethylene range between US$1.85 and US$2.06 (Jan 2011 US$). This compares to US$1.17 per kg for fossil‐based ethylene. Waste‐derived ethylene breaks even with its fossil‐based counterpart at a tipping fee of roughly US$42 per metric ton of waste feedstock.  相似文献   

4.
The environmental impact of the management of biodegradable waste in Stockholm, based mainly on incineration and landfilling, was compared to systems with significant nutrient recycling; large-scale composting, anaerobic digestion, and separate collection and utilization of urine. The systems' emissions, residual products, energy turnover, and resource consumption were evaluated from a life-cycle perspective, using a computerized model, ORWARE (ORganic WAste REsearch model).
Transportation was of relatively low importance to overall environmental impact, even at high rates of nutrient recycling. This is remarkable considering the geographical setting of Stockholm, with high population density and little nearby farmland. Ancillary systems, such as generation of electricity and district heating, were crucial for the overall outcome.
Increased recycling of nutrients in solid biodegradable waste in Stockholm can reduce net environmental impact, whereas separation of human urine to be spread as fertilizer cannot yet be introduced without increased acidification. Increased nutrient recycling from solid biodegradable waste inevitably increases spreading of metals on arable land. Urine is by far the least contaminated residual product. Spreading of all other residuals would be limited by their metal content.  相似文献   

5.
《Biotechnology advances》2017,35(6):758-771
Microbial electrolysis cells (MECs) are a promising technology for biological hydrogen production. Compared to abiotic water electrolysis, a much lower electrical voltage (~ 0.2 V) is required for hydrogen production in MECs. It is also an attractive waste treatment technology as a variety of biodegradable substances can be used as the process feedstock. Underpinning this technology is a recently discovered bioelectrochemical pathway known as “bioelectrohydrogenesis”. However, little is known about the mechanism of this pathway, and numerous hurdles are yet to be addressed to maximize hydrogen yield and purity. Here, we review various aspects including reactor configurations, microorganisms, substrates, electrode materials, and inhibitors of methanogenesis in order to improve hydrogen generation in MECs.  相似文献   

6.
Like many economic exchanges, industrial symbiosis (IS) is thought to be influenced by social relationships and shared norms among actors in a network. While many implicit references to social characteristics exist throughout the literature, there have been few explicit attempts to operationalize and measure the concepts. The “short mental distance,”“trust,”“openness,” and “communication” recorded among managers in Kalundborg, Denmark, set a precedent for examining and encouraging social interactions among key personnel in the dozens of eco‐industrial networks around the world. In this article we explore the relationships among various aspects of social embeddedness, social capital, and IS. We develop a conceptual framework and an approach using quantitative and qualitative methods to identify and measure these social characteristics, including social network structure, communication, and similarities in norms and conceptions of waste, and apply them in an industrial network in Nanjangud, South India. The findings suggest that there is a fairly high level of shared norms about dealing with waste—the “short mental distance”—in this network, but by‐product transactions are only weakly correlated with the structure and content of communication among managers. Replication of this approach can increase the understanding and comparability of the role of social characteristics in eco‐industrial activities around the world.  相似文献   

7.
Aim, Scope and Background  When materials are recycled they are made available for use for several future life cycles and can therefore replace virgin material more than just once. In order to analyse the optimal waste management system for a given material, the authors have analysed the material flows in a life cycle perspective. It is important to distinguish this approach for material flow analysis for a given material from life cycle analysis of products. A product life cycle analysis analyses the product system from cradle to grave, but uses some form of allocation in order to separate the life cycle of one product from another in cases where component materials are recycled. This paper does not address allocation of burdens between different product systems, but rather focuses on methodology for decision making for waste management systems where the optimal waste management system for a given material is analysed. The focus here is the flow of the given material from cradle (raw material extraction) to grave (the material, or its inherent energy, is no longer available for use). The limitation on the number of times materials can be recycled is set by either the recycling rate, or the technical properties of the recycled material. Main Features  This article describes a mathematical geometric progression approach that can be used to expand the system boundaries and allow for recycling a given number of times. Case studies for polyethylene and paperboard are used to illustrate the importance of including these aspects when part of the Goal and Scope for the LCA study is to identify which waste management treatment options are best for a given material. The results and discussion examine the different conclusions that can be reached about which waste management option is most environmentally beneficial when the higher burdens and benefits of recycling several times are taken into account. Results  In order to assess the complete picture of the burdens and benefits arising from recycling the system boundaries must be expanded to allow for recycling many times. A mathematical geometric progression approach manages to take into account the higher burdens and benefits arising from recycling several times. If one compares different waste management systems, e.g. energy recovery with recycling, without expanding the system to include the complete effects of material recycling one can reach a different conclusion about which waste management option is preferred. Conclusions  When the purpose of the study is to compare different waste management options, it is important that the system boundaries are expanded in order to include several recycling loops where this is a physical reality. The equations given in this article can be used to include these recycling loops. The error introduced by not expanding the system boundaries can be significant. This error can be large enough to change the conclusions of a comparative study, such that material recycling followed by incineration is a much better option than waste incineration directly. Recommendations and Outlook  When comparing waste management solutions, where material recycling is a feasible option, it is important to include the relevant number of recycling loops to ensure that the benefits of material recycling are not underestimated. The methodology presented in this article should be used in future comparative studies for strategic decision-making for waste management. The approach should not be used for LCAs for product systems without due care, as this could lead to double counting of the benefits of recycling (depending on the goal and scope of the analysis). For materials where the material cycle is more of a closed loop and one cannot truly say that recycled materials replace virgin materials, a more sophisticated approach will be required, taking into account the fact that recycled materials will only replace a certain proportion of virgin materials.  相似文献   

8.
This article addresses a market‐based management concept for waste electrical and electronic equipment (WEEE) known as the “best‐of‐two‐worlds” approach. The concept is based on the idea that recyclers in developing countries and emerging economies can cooperate with technologically advanced refineries in industrialized countries to facilitate efficient recovery of valuable metals, such as gold and palladium, from e‐waste. The article provides an overview of technical and environmental concerns underlying the concept and sheds light on the political framework, the waste‐related trade issues, and the resource economics that need to be considered for further decision making. Building on this synthesis, I conduct a qualitative assessment of sustainability impacts of the proposed concept by analyzing two scenarios and their associated risks. The analysis suggests that, under certain preconditions, the best‐of‐two‐worlds concept could yield significant improvements in terms of management of hazardous substances, resource efficiency, greenhouse gas emissions, income generation, and investments into social and environmental standards. Generally, two potential implementation scenarios were identified: Whereas under Scenario 1 only WEEE generated within developing countries and emerging economies is managed through the best‐of‐two‐worlds approach, Scenario 2 additionally incorporates WEEE imported from industrialized countries. Although both scenarios can yield a variety of benefits, Scenario 2 might cause a net flow of hazardous substances from industrialized countries into developing countries and emerging economies, thus leading to less beneficial sustainability impacts.  相似文献   

9.
This study investigates the benefits of waste management policies on gaseous emissions and resource consumption caused by the final demand, in the specific case of France and in a context of economic growth. Waste input‐output analysis is implemented to compare three scenarios, depicting and combining the upward trend of final demand from 2008 to 2020, the increase in recycling rates by 2020 (encompassing the achievement of recycling objectives set by European Union Directives), and the simultaneous larger implementation of best available techniques (BAT) for waste incineration. Hybrid monetary physical input‐output tables are initially derived from balanced physical supply and use tables and further complemented with process inventory data on waste treatment technologies. A dramatic reduction in the demand for primary metals (by a factor of 2.0) and for primary mining and quarrying products for construction (by a factor of 1.9) is observed in 2020, as compared to 2008, in the case of the scenario “recycling,” despite the competition induced by the evolution of the final demand. On the contrary, considering energy requirements and fossil carbon dioxide, sulfur dioxide, and nitrogen oxide emissions caused by the French final demand, the combined improvements in recycling and incineration performances by 2020 would only limit the rise induced by the evolution of the final demand. On the basis of these results, the potential contribution of waste management policies to the decoupling of resource consumption and gaseous emissions from final demand's growth is finally discussed.  相似文献   

10.
Abstract: In a life‐cycle assessment (LCA) involving only one of several products from the same process, how are the resource consumption and the emissions associated with this process to be partitioned and distributed over these co‐products? This is the central question in co‐product allocation, which has been one of the most controversial issues in the development of the methodology for life‐cycle assessment, as it may significantly influence or even determine the result of the assessments. In this article, it is shown that in prospective life‐cycle assessments, co‐product allocation can always be avoided by system expansion. Through a number of examples, it is demonstrated how system expansion is performed, with special emphasis on issues that earlier have been a focus of the allocation debate, such as joint production (e.g., of chlorine and sodium hydroxide, zinc and heavy metals, and electricity and heat), the handling of “near‐to‐waste” by‐products, processes simultaneously supplying services to multiple product systems, and credits for material recycling and downcycling. It is shown that all the different co‐product situations can be covered by the same theoretical model and the same practical procedure, and that it is also possible to include the traditional co‐product allocation as a special case of the presented procedure. The uncertainty aspects of the presented procedure are discussed. A comparison is made with the procedure of ISO 14041, “Life‐cycle assessment—Goal and scope definition and inventory analysis,” the international standard.  相似文献   

11.
China produces and consumes a large amount of batteries annually, which leads to many waste batteries needing to be recycled. The collection and recycling system of primary, alkaline secondary, and lithium‐ion secondary batteries in China is particularly poor, and waste battery recycling enterprises generally sustain economic losses if they solely use waste batteries as raw materials. Increasing the profits of waste battery recycling systems is a key problem that needs to be considered. This article quantitatively analyzes waste battery generation in China by using annual sales data and probable lifetime distribution of various batteries. The results show that the rapid growth of battery usage has led to an increased generation of waste batteries and the percentage of different types of waste batteries is changing over time. In 2013, the total quantity of all waste batteries in the medium lifetime scenario reached 570 kilotons, of which primary, alkaline secondary, and lithium‐ion secondary waste batteries accounted for approximately 36%, 28%, and 35%, respectively. Based on a real‐world case study of a typical domestic waste battery recycling enterprise in China, material flow analysis and cost‐benefit analysis were conducted to study the development of the recycling process of comingled waste batteries. Through scenario analysis, we conclude that increasing the use of waste batteries as raw materials and the recycling of other materials that are less valuable reduces the profits of the waste battery recycling enterprise. Higher profits can be achieved by adding the production of high value‐added downstream products and government support. At the same time, the essential role of the government in developing a waste battery recycling system was identified. Finally, relevant suggestions are made for improvements in both the government and enterprise sectors.  相似文献   

12.
Experiments with gummy bears With gelatin in the form of gummy bears, the differences to vegetable gelling agents can be easily demonstrated by simple experiments. How these gummy bears can also be used to produce sustainable labels is shown in this article. The presented experiments and instructions are part of a experiment kit with teaching materials for the implementation of a project week in schools with the topic “sustainability”.  相似文献   

13.
Extended producer responsibility (EPR) policies have proven effective at raising consumer awareness, expanding waste collection infrastructure, and shifting costs of end‐of‐life (EOL) management from municipalities to stewardship organizations. Yet, such policies have been less successful in advancing waste management programs that ensure a net environmental benefit. This article analyzes how EPR policies for single‐use batteries in the European Union (EU), Canada, and the United States address the environmental costs and benefits of EOL management. Considering these EPR policies is instructive, because single‐use batteries have high collection costs and are of relatively low economic value for waste processors. Without deliberate planning, the environmental burdens of collecting and recycling such batteries may exceed the benefits. This article considers how EPR policies for single‐use batteries integrate performance requirements such as collection rates, recycling efficiencies, and best available techniques. It argues that for such policies to be effective, they need to be extended to address waste collection practices, the life cycle consequences of EOL management, and the quality of recovered materials. Such strategies are relevant to EPR policies for other products with marginal secondary value, including some textiles, plastics, and other types of electronic waste.  相似文献   

14.

Purpose

Approximately 46,000 t/day of packaging waste was generated in China in 2010, of which, 2,500 t was composite packaging waste. Due to the lack of recycling technology and an imperfect recovery system, most of this waste is processed in sanitary landfills. An effective packaging waste management system is needed since this waste not only uses up valuable resources, but also increases environmental pollution. The purpose of this study is to estimate the environmental impact of the treatment scenarios in composite packaging waste which are commonly used in China, to determine the optimum composite packaging waste management strategy, and to design new separating and recycling technology for composite packaging, based on the life cycle assessment (LCA) results.

Methods

To identify the best treatment for composite packaging waste, the LCA software SimaPro 7.1.6 was used to assist in the analysis of the environmental impacts, coupled with the impact assessment method Eco-Indicator 99. LCA for composite packaging waste management was carried out by estimating the environmental impacts of the four scenarios most often used in China: landfill, incineration, paper recycling, and separation of polyethylene and aluminum. One ton of post-consumption Tetra Pak waste was selected as the functional unit. The data on the mass, energy fluxes, and environmental emissions were obtained from literature and site investigations.

Results and discussion

Landfill—scenario 1—was the worst waste management option. Paper recycling—scenario 3—was more environmentally friendly than incineration, scenario 2. Scenario 4, separating out polyethylene and aluminum, was established based on the LCA result, and inventory data were obtained from the demonstration project built by this research. In scenario 4, the demonstration project for the separation of polyethylene and aluminum was built based on the optimum conditions from single-factor and orthogonal experiments. Adding this flow process into the life cycle of composite packaging waste treatment decreased the environmental impacts significantly.

Conclusions

The research results can provide useful scientific information for policymakers in China to make decisions regarding composite packaging waste. Incineration could reduce more environmental impacts in the respiratory inorganics category, and separation of polyethylene and aluminum, in the fossil fuel category. If energy saving is the primary governmental goal, the separation of polyethylene and aluminum would be the better choice, while incineration would be the better choice for emission reduction.  相似文献   

15.
Studies in both terrestrial and aquatic ecosystems have documented the potential importance of consumers on ecosystem‐level nutrient dynamics. This is especially true when aggregations of organisms create biogeochemical hotspots through nutrient consumption, assimilation, and remineralization via excretion and egestion. Here, we focused on aggregations of humans in cities to examine how diet and waste management interact to drive nitrogen‐ (N) and phosphorus‐ (P) fluxes into nutrient pollution, inert forms, and nutrient recycling. We constructed six diet patterns (five US‐based and one developing nation) to examine N‐ and P‐consumption and excretion, and explored their implications for human health. Next, we constructed six waste‐management patterns (three US and three for developing nations) to model how decisions at household and city scales determine the eventual fates of N and P. When compared to the US Recommended Daily Intake, all US diet patterns exceeded N and P requirements. Other than the “enriched CO2 environment scenario” diet, the typical US omnivore had the greatest excess (37% N and 62% P). Notably, P from food additives could account for all of the excess P found in US omnivore and vegetarian diets. Across all waste‐management approaches, a greater proportion of P was stored or recycled (0 to > 100% more P than N) and a greater proportion of N was released as effluent (20 to > 100% more N than P) resulting in pollution enriched with N and a recycling stream enriched with P. In developing nations, 60% of N and 50% of P from excreta entered the environment as pollution because of a lack of sanitation infrastructure. Our study demonstrates a novel addition to modeling sustainable scenarios for urban N‐ and P‐budgets by linking human diets and waste management through socio‐ecological systems.  相似文献   

16.
Electronic textiles are a vanguard of an emerging generation of smart products. They consist of small electronic devices that are seamlessly embedded into clothing and technical textiles. E‐textiles provide enhanced functions in a variety of unobtrusive and convenient ways. Like many high‐tech products, e‐textiles may evolve to become a mass market in the future. In this case, large amounts of difficult‐to‐recycle products will be discarded. That can result in new waste problems. This article examines the possible end‐of‐life implications of textile‐integrated electronic waste. As a basis for assessment, the innovation trends of e‐textiles are reviewed, and an overview of their material composition is provided. Next, scenarios are developed to estimate the magnitude of future e‐textile waste streams. On that base, established disposal and recycling routes for e‐waste and old textiles are assessed in regard to their capabilities to process a blended feedstock of electronic and textile materials. The results suggest that recycling old e‐textiles will be difficult because valuable materials are dispersed in large amounts of heterogeneous textile waste. Moreover, the electronic components can act as contaminants in the recycling of textile materials. We recommend scrutinizing the innovation trend of technological convergence from the life cycle perspective. Technology developers and product designers should implement waste preventative measures at the early phases in the development process of the emerging technology.  相似文献   

17.
The so‐called iodine test is ideal for demonstrating the role of the enzyme “amylase” in simple experiments based on a colour reaction when a yeast dough rises, when carbohydrates are digested or when dishes are washed in the dishwasher. The experiments presented can be used to clarify the question of which everyday substances are capable of degrading starch or whether a food contains starch or not. The central question of the experiments is, how yeast makes the bread dough rise despite of its “starch intolerance”.  相似文献   

18.
The market for photovoltaic (PV) electricity generation has boomed over the last decade, and its expansion is expected to continue with the development of new technologies. Taking into consideration the usage of valuable resources and the generation of emissions in the life cycle of photovoltaic technologies dictates proactive planning for a sound PV recycling infrastructure to ensure its sustainability. PV is expected to be a “green” technology, and properly planning for recycling will offer the opportunity to make it a “double‐green” technology—that is, enhancing life cycle environmental quality. In addition, economic feasibility and a sufficient level of value‐added opportunity must be ensured, to stimulate a recycling industry. In this article, we survey mathematical models of the infrastructure of recycling processes of other products and identify the challenges for setting up an efficient one for PV. Then we present an operational model for an actual recycling process of a thin‐film PV technology. We found that for the case examined with our model, some of the scenarios indicate profitable recycling, whereas in other scenarios it is unprofitable. Scenario SC4, which represents the most favorable scenario by considering the lower bounds of all costs and the upper bound of all revenues, produces a monthly profit of $107,000, whereas the least favorable scenario incurs a monthly loss of $151,000. Our intent is to extend the model as a foundation for developing a framework for building a generalized model for current‐PV and future‐PV technologies.  相似文献   

19.
Extended producer responsibility (EPR), which assigns significant responsibility to producers to take back their end‐of‐life products to create incentives for redesign of products with lower life cycle environmental impacts, has come to a crossroad facing a trade‐off between the original innovation‐oriented regime design and the cost‐efficiency challenges in practice. This is particularly true in its implementation in non‐Organization for Economic Co‐operation and Development (OECD) countries as they are trying to transplant the “best practices” from OECD countries, for there is increasing skepticism as to whether EPR is suitable for developing countries at all. As an important producer of electronic products and destination of electronic waste (e‐waste) flows in the world, China has been expected to play a vital role in the evolution of global governance based on the idea of EPR, either to create new ways for producers to perform their end‐of‐life strategies, or to reshape the mode of production and consumption with its fast‐growing market. However, the establishment of EPR in China has been long and full of difficulties. This article reviews the status and trends in the establishment of an EPR system for waste electrical and electronic equipment (WEEE) management in China. We use the framework of a multilevel perspective of transition theory in our analysis to characterize the complex interactions among various agents in the evolution of the Chinese system from initial innovation‐oriented design to the current efficiency‐oriented version. An ongoing research framework for evaluation of the EPR program in China is outlined as the research agenda in coming years.  相似文献   

20.
In this article, we explore several options for linking information technology to materials and products through the use of bar codes and radio-frequency identification (RFID) tags, and the implications for product life-cycle management. We also describe tests with existing and modified tags, both on and inside products, as would be needed for environmental management applications.
Bar codes are cheap and have an existing infrastructure; RFID tags are more expensive and less widespread, but they can be read without a line of sight between the tag and the reader. Bar codes and RFID tags carrying basic product information could link to different databases for a range of applications. Product tags could increase recycling efficiency by automating the sorting of recyclables or by linking to product dismantling instructions during the recycling process. Product tags could provide incentives for good waste management, through Universal Product Code (UPC) bar-code recycling coupons or through RFID tag automatic recycling credits for curbside collection programs. Measures to encourage the development of these types of applications include moves toward competitive, market-based waste management systems, the encouragement of experimental systems, and coordination between manufacturers and waste management industries.  相似文献   

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