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1.
A tax on waste-to-energy incineration of fossil carbon in municipal solid waste from households was introduced in Sweden on July 1, 2006. The tax has led to higher incineration gate fees. One of the main purposes with the tax is to increase the incentive for recycling of materials, including biological treatment. We investigate whether and to what extent this effect can be expected. A spreadsheet model is developed in order to estimate the net marginal cost of alternative waste treatment methods, i.e., the marginal cost of alternative treatment minus avoided cost of incineration. The value of the households’ time needed for source separation is discussed and included. The model includes the nine largest fractions, totalling 85% (weight), of the household waste currently being sent to waste incineration: food waste, newsprint, paper packaging, soft and hard plastic packaging, diapers, yard waste, other paper waste, and non-combustible waste. Our results indicate that the incineration tax will have the largest effect on biological treatment of kitchen and garden waste, which may increase by 9%. The consequences of an incineration tax depend on: (a) the level of the tax, (b) whether the tax is based on an assumed average Swedish fossil carbon content or on the measured carbon content in each incineration plant, (c) institutional factors such as the cooperation between waste incinerators, and (d) technological factors such as the availability of central sorting of waste or techniques for measurement of fossil carbon in exhaust gases, etc. Information turns out to be a key factor in transferring the governing force of the tax to the households as well improving the households’ attitudes towards material recycling.  相似文献   

2.
Waste management activities contribute to global greenhouse gas emissions approximately by 4%. In particular the disposal of waste in landfills generates methane that has high global warming potential. Effective mitigation of greenhouse gas emissions is important and could provide environmental benefits and sustainable development, as well as reduce adverse impacts on public health. The European and UK waste policy force sustainable waste management and especially diversion from landfill, through reduction, reuse, recycling and composting, and recovery of value from waste. Energy from waste is a waste management option that could provide diversion from landfill and at the same time save a significant amount of greenhouse gas emissions, since it recovers energy from waste which usually replaces an equivalent amount of energy generated from fossil fuels. Energy from waste is a wide definition and includes technologies such as incineration of waste with energy recovery, or combustion of waste-derived fuels for energy production or advanced thermal treatment of waste with technologies such as gasification and pyrolysis, with energy recovery. The present study assessed the greenhouse gas emission impacts of three technologies that could be used for the treatment of Municipal Solid Waste in order to recover energy from it. These technologies are Mass Burn Incineration with energy recovery, Mechanical Biological Treatment via bio-drying and Mechanical Heat Treatment, which is a relatively new and uninvestigated method, compared to the other two. Mechanical Biological Treatment and Mechanical Heat Treatment can turn Municipal Solid Waste into Solid Recovered Fuel that could be combusted for energy production or replace other fuels in various industrial processes. The analysis showed that performance of these two technologies depends strongly on the final use of the produced fuel and they could produce GHG emissions savings only when there is end market for the fuel. On the other hand Mass Burn Incineration generates greenhouse gas emission savings when it recovers electricity and heat. Moreover the study found that the expected increase on the amount of Municipal Solid Waste treated for energy recovery in England by 2020 could save greenhouse gas emission, if certain Energy from Waste technologies would be applied, under certain conditions.  相似文献   

3.
In 1992, Sweden introduced a producer responsibility ordinance which explicitly states that sorted out, collected waste paper must be material recycled. Another alternative could be to recover energy by incineration. Material recycling was prioritized, although there is no environmental consensus favouring either of the alternatives. By calculating shadow prices of waste paper for the paper industry and for the heating plants, this study tries to determine whether waste paper should be partly incinerated. The study also addresses whether the producer responsibility has contributed to an inefficient allocation of waste paper. The results find no economic support for the producer responsibility.  相似文献   

4.
A tax on waste-to-energy incineration of fossil carbon in municipal solid waste from households was introduced in Sweden on July 1, 2006. The tax has led to higher incineration gate fees. One of the main purposes with the tax is to increase the incentive for recycling of materials, including biological treatment. We investigate whether and to what extent this effect can be expected. A spreadsheet model is developed in order to estimate the net marginal cost of alternative waste treatment methods, i.e., the marginal cost of alternative treatment minus avoided cost of incineration. The value of the households’ time needed for source separation is discussed and included. The model includes the nine largest fractions, totalling 85% (weight), of the household waste currently being sent to waste incineration: food waste, newsprint, paper packaging, soft and hard plastic packaging, diapers, yard waste, other paper waste, and non-combustible waste. Our results indicate that the incineration tax will have the largest effect on biological treatment of kitchen and garden waste, which may increase by 9%. The consequences of an incineration tax depend on: (a) the level of the tax, (b) whether the tax is based on an assumed average Swedish fossil carbon content or on the measured carbon content in each incineration plant, (c) institutional factors such as the cooperation between waste incinerators, and (d) technological factors such as the availability of central sorting of waste or techniques for measurement of fossil carbon in exhaust gases, etc. Information turns out to be a key factor in transferring the governing force of the tax to the households as well improving the households’ attitudes towards material recycling.  相似文献   

5.
Abstract

This article presents a case study of a projected solar assisted biomass district heating system in the north of Sweden. It is generally known that a biomass district heating system combined with solar heat brings many important benefits. The most common system solution is to install a heat store and a large solar collector field near the heating central. No plant of this type is however in operation in the northern part of Sweden. The main reason for this is that the solar irradiation at these latitudes is very low when the demand for heat is high. Solar heat could however be useful during summer in order to generate hot tap water. One problem is that the heat losses, calculated as percentage of the delivered heat, become very large during these months. This article presents the idea of allowing the connected households to generate their own hot tap water using solar collectors and heat stores installed in each house. The district heating network can therefore be closed in summer, which eliminates the heat losses outside the heating period. A case study of a projected plant has been carried out and it is shown that it is possible to reduce the heat losses by 20% compared to a conventional system. This idea also provides many other important technical and economic benefits.  相似文献   

6.
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.  相似文献   

7.
The management of the plastic fraction is one of the most debated issues in the discussion on integrated municipal solid waste systems. Both material and energy recovery can be performed on such a waste stream, and different separate collection schemes can be implemented. The aim of the paper is to contribute to the debate, based on the analysis of different plastic waste recovery routes. Five scenarios were defined and modelled with a life cycle assessment approach using the EASEWASTE model. In the baseline scenario (P0) the plastic is treated as residual waste and routed partly to incineration with energy recovery and partly to mechanical biological treatment. A range of potential improvements in plastic management is introduced in the other four scenarios (P1–P4). P1 includes a source separation of clean plastic fractions for material recycling, whereas P2 a source separation of mixed plastic fraction for mechanical upgrading and separation into specific polymer types, with the residual plastic fraction being down-cycled and used for “wood items”. In P3 a mixed plastic fraction is source separated together with metals in a “dry bin”. In P4 plastic is mechanically separated from residual waste prior to incineration.A sensitivity analysis on the marginal energy was carried out. Scenarios were modelled as a first step assuming that marginal electricity and heat were based on coal and on a mix of fuels and then, in the sensitivity analysis, the marginal energy was based on natural gas.The study confirmed the difficulty to clearly identify an optimal strategy for plastic waste management. In fact none of the examined scenarios emerged univocally as the best option for all impact categories. When moving from the P0 treatment strategy to the other scenarios, substantial improvements can be obtained for “Global Warming”. For the other impact categories, results are affected by the assumption about the substituted marginal energy. Nevertheless, irrespective of the assumptions on marginal energy, scenario P4, which implies the highest quantities of specific polymer types sent to recycling, resulted the best option in most impact categories.  相似文献   

8.
Municipal solid waste (MSW) disposal and management is one of the most significant challenges faced by urban communities around the world. Municipal solid waste management (MSWM) over the years has utilized many sophisticated technologies and smart strategies. Municipalities worldwide have pursued numerous initiatives to reduce the environmental burden of the MSW treatment strategies. One of the most beneficial MSWM strategies is the thermal treatment or energy recovery to obtain cleaner renewable energy from waste. Among many waste-to-energy strategies, refuse-derived fuel (RDF) is a solid recovered fuel that can be used as a substitute for conventional fossil fuel. The scope of this study is to investigate the feasibility of RDF production with MSW generated in Metro Vancouver, for co-processing in two cement kilns in the region. This study investigates environmental impacts and benefits and economic costs and profits of RDF production. In addition, RDF utilization as an alternative fuel in cement kilns has been assessed. Cement manufacturing has been selected as one of the most environmentally challenged industries and as a potential destination for RDF to replace a portion of conventional fossil fuels with less energy-intensive fuel. A comprehensive environmental assessment is conducted using a life cycle assessment (LCA) approach. In addition, cost–benefit analysis (CBA) has been carried out to study the economic factors. This research confirmed that RDF production and use in cement kilns can be environmentally and economically viable solution for Metro Vancouver.  相似文献   

9.
The management system for solid and liquid organic waste affects the environment and surrounding technical systems in several ways. In order to decrease the environmental impact and resource use, biological waste treatment and alternative solutions for sewage treatment are often advocated. These alternatives include increased agricultural use of waste residuals. To analyse whether such proposed systems indicate improvements for the environment and its sustainability, systems analysis is a useful method. The changes in environmental impact and resource use is not only a result of changes in waste treatment methods, but also largely a result of changes in surrounding systems (energy and agriculture) caused by changes in waste management practices. In order to perform a systems analysis, a substance-flow simulation model, the organic waste research model (ORWARE), has been used. The results are evaluated by using methodology from life cycle assessment (LCA). An economic analysis was also performed on three of the studied scenarios. The management system for solid organic waste and sewage in the municipality of Uppsala, Sweden, was studied. Three scenarios for different treatments of solid waste were analysed: incineration with heat recovery, composting, and anaerobic digestion. These three scenarios included conventional sewage treatment. A fourth scenario reviewed was anaerobic digestion of solid waste, using urine-separating toilets and separate handling of the urine fraction. The results are only valid for the case study and under the assumptions made. In this case study anaerobic digestion result in the lowest environmental impact of all the solid waste management systems, but is costly. Economically, incineration with heat recovery is the cheapest way to treat solid waste. Composting gives environmental advantages compared to incineration methods, without significantly increased costs. Urine separation, which may be implemented together with any solid waste treatment, has great advantages, particularly in its low impact on the environment. However, there is a large increase in acidification.  相似文献   

10.
Food waste can be valorized through different technologies, such as anaerobic digestion, incineration, and animal feed production. In this study we analyzed the environmental performance of two food waste valorization scenarios from a company of the retail sector in Belgium, through exergy analysis, exergetic life cycle assessment (ELCA), and a traditional life cycle assessment (LCA). In scenario 1 all food waste was considered to be valorized in an anaerobic digestion (producing electricity, heat, digestate and sorting the packaging material to be used as fuel for cement industry), while in scenario 2 a bread fraction was valorized to produce animal feed and a non-bread fraction was valorized in an anaerobic digestion (producing the same products on scenario 1, but in lower amounts). Scenario 2 was 10% more efficient than scenario 1 in the exergy analysis. For the ELCA and the single score LCA, scenario 2 presented lower environmental impacts than scenario 1 (32% and 26% lower, respectively). These results were mainly due to the avoided products from traditional supply chain (animal feed produced from agricultural products) and lower exergy loss at the feed production plant. Nevertheless, the high dry matter content of the bread waste played an important role on these results, therefore it should be pointed out that valorizing food waste to animal feed seems to be a better option only for the fractions of food waste with low water content (as bread waste).  相似文献   

11.
Plastics have become an indispensable ingredient of human life. They are non-biodegradable polymers of mostly containing carbon, hydrogen, and few other elements such as chlorine, nitrogen etc. Rapid growth of the world population led to increased demand of commodity plastics. High density poly ethylene is one of the largest used commodity plastics due to its vast applications in many fields. Due to its non bio degradability and low life, HDPE contributes significantly to the problem of Municipal Waste Management. To avert environment pollution of HDPE wastes, they must be recycled and recovered. On the other hand, steady depletion of fossil fuel and increased energy demand, motivated the researchers and technologists to search and develop different energy sources. Waste to energy has been a significant way to utilize the waste sustainably, simultaneously add to meet the energy demand. Plastics being petrochemical origin have inherently high calorific value. Thus they can be converted back to useful energy. Many researches have been carried out to convert the waste plastics into liquid fuel by thermal and catalytic pyrolysis and this has led to establishment of a number of successful firms converting waste plastics to liquid fuels. This paper reviews the production and consumption HDPE, different methods of recycling of plastic with special reference to chemical degradation of HDPE to fuel. This also focuses on different factors that affect these degradations, the kinetics and mechanism of this reaction.  相似文献   

12.
This article presents a general multi-objective mixed-integer linear programming (MILP) optimization model aimed at providing decision support for waste and resources management in industrial networks. The MILP model combines material flow analysis, process models of waste treatments and other industrial processes, life cycle assessment, and mathematical optimization techniques within a unified framework. The optimization is based on a simplified representation of industrial networks that makes use of linear process models to describe the flows of mass and energy. Waste-specific characteristics, e.g. heating value or heavy metal contamination, are considered explicitly along with potential technologies or process configurations. The systems perspective, including both provision of waste treatment and industrial production, enables constraints imposed upon the systems, e.g. available treatment capacities, to be explicitly considered in the model. The model output is a set of alternative system configurations in terms of distribution of waste and resources that optimize environmental and economic performance. The MILP also enables quantification of the improvement potential compared to a given reference state. Trade-offs between conflicting objectives are identified through the generation of a set of Pareto-efficient solutions. This information supports the decision making process by revealing the quantified performance of the efficient trade-offs without relying on weighting being expressed prior to the analysis. Key features of the modeling approach are illustrated in a hypothetical case. The optimization model described in this article is applied in a subsequent paper (Part II) to assess and optimize the thermal treatment of sewage sludge in a region in Switzerland.  相似文献   

13.
为进一步完善我国废物焚烧标准体系,防控废物焚烧环境风险,本文对欧盟废物焚烧指令与我国焚烧标准体系进行了对比分析。欧盟废物焚烧指令分别对专用焚烧厂和协同焚烧厂从废物运输到处理处置全过程的污染物排放控制做出了相关规定,适用于危险废物和非危险废物的焚烧以及常规污染物和有毒污染物的控制。欧盟废物焚烧指令对不同规模的焚烧设施采用统一标准,以日均值和半小时均值为污染物排放限值,更客观、准确地评价了污染物排放对环境的影响。与欧盟废物焚烧指令相比,我国废物焚烧标准涉及废物联合利用处置的相关条文较少,内容不详,项目缺失。我国烟尘、HCl的排放限值均在欧盟标准限值6倍以上,SO2的排放限值是欧盟标准的4~8倍。除CO、NOx的排放限值外,其他污染物排放限值也明显高于欧盟标准限值。我国采用抽样监测方法,监测结果可能在日常排放值的95%置信区间外,不具备代表性。我国可借鉴欧盟废物焚烧指令的成果制定协同焚烧标准,并严格污染物排放限值,考虑采用日均值或半小时均值的评价方法,提高我国废物焚烧标准的精确性和可执行性。  相似文献   

14.
Pyrolysis is considered as possible technique to thermally convert waste plastics into chemicals and energy. Literature on experimental findings is extensive, although experiments are mostly performed in a dynamic heating mode, using thermogravimetric analysis (TGA) and at low values of the heating rate (mostly below 30 K/min). The present research differs from literature through the application of far higher heating rates, up to 120 K/min. The use of these dynamic results to define the reaction kinetics necessitates the selection of an appropriate reaction mechanism, and 21 models have been proposed in literature considering the rate limiting step being diffusion, nucleation or the reaction itself.The current research studied the cracking of PET and PS by TGA at different heating rates (temperature ramps). Results were used to check the validity of the proposed mechanisms. Several conclusions are drawn: (i) to obtain fair results, the heating ramp should exceed a minimum value, calculated at 30 K/min for PET and 80 K/min for PS; (ii) application of the majority of the models to experimental findings demonstrated that they do not meet fundamental kinetic considerations and are questionable in their use; and (iii) simple models, with reaction order 1 or 2, provide similar results of the reaction activation energy.A further comparison with literature data for dynamic and isothermal experiments confirms the validity of these selected models. Since TGA results are obtained on a limited amount of sample, with results being a strong function of the applied heating rate, the authors believe that isothermal experiments, preferably on a large scale both towards equipment and/or sample size, are to be preferred.  相似文献   

15.
The environmental performance of the University of Maribor (Engineering Campus) has been assessed on a life cycle basis. The following activities have been considered in the study: the use and operation of lecture theatres (construction and maintenance, heating, lighting and water consumption) and day-to-day consumption of sundries (paper and plastic bottles). The results indicate that the heating and construction of buildings are the ‘hot spots’ in the system, for most environmental impacts. Different waste management options for the plastic and paper, including recycling, incineration and landfill, have also been compared for environmental impacts and economic costs. The option combining 70% recycling, 29% incineration and 1% landfill has been found to be most economically and environmentally sustainable.  相似文献   

16.
Industrial waste is a good resource from the viewpoint of efficient waste management. The vital need for energy utilization and environmental protection mean it is of interest to develop circulating fluidized bed combustion (CFBC) to burn solid wastes with low pollutant emissions. The paper presents some explanatory studies on waste-to-energy in a pilot scale CFCB facility. A series of combustion/incineration tests have been carried out for the industrial wastes: petroleum coke, waste tire and sludge cakes with various moisture contents. It seems that the CFBC has feed flexibility without modifying heat transfer equipments for energy recovery. In addition, the results of experimental tests demonstrate that gas emissions from waste incineration in CFBC can be well controlled under local regulation limits.At normal operation temperature in CFBC (approx. 800°C), the heat transfer coefficient between bulk bed and bed wall is on the order of 102 W/m C, which is useful to estimate the energy recovery of waste combustion by CFBC. A practical and simple guide is proposed to estimate the energy recovery from waste combustion by CFBC, and to find maximum allowable moisture content of waste if there is to be any energy recovery without auxiliary fuel.  相似文献   

17.
This paper reviews the evolution of energy use in Sweden since the early 1970s to shed light on the future, with emphasis on the role of energy efficiency. Between 1973 and 1989 improvements in end-use energy efficiency saved 8% of Sweden's primary energy use and 24% of Sweden's delivered energy use. These savings were concentrated in the residential and manufacturing sectors, with important savings also occurring in air travel and the heating of commercial buildings. Despite these accomplishments, we found that Sweden was well behind Denmark, FRGermany, Japan and the USA in energy savings during this period. At the beginning of the 1990s Sweden exhibited one of the most energy intensive economic structures in the OECD. Sweden now faces many dilemmas that will influence future energy use: the role of nuclear power, pricing and taxation policies for fuels and electricity, the future of subsidies for housing and travel, the role of Sweden's energy intensive exports, and indeed the very lifestyle of the Swedes.  相似文献   

18.
The urban waste treatment service has been a sensitive issue for the Portuguese governments in the past decades. Among other measures, the environmental and economical issues led to the creation of a sector-specific regulator for the waste sector. Considering this atypical circumstance in the worldwide context it is worth studying the external factors that may influence the waste utilities efficiency along with the regulation role. In this regard, we applied the parametric approach of the stochastic frontier analysis to evaluate the influence of the operational environment on the urban waste services performance. The sample included 32 utilities responsible for the waste treatment service in Portugal. The results showed a negative influence of factors, such as the existence of regulation, the distance to the waste treatment facilities and the provision of other services on utility performance. We also observed some benefits from privatisation and incineration, although these options have some particular features.  相似文献   

19.
In policy support of municipal solid waste (MSW) management, life cycle assessment (LCA) can serve to compare the environmental or economic impacts of two or more options for waste processing. The scope of waste management LCAs generally focuses less attention on future developments, e.g., where will recycling take place, and more on the environmental performance of prototypes, e.g., the incineration of all waste compared to recycling. To provide more robust support for Swiss waste glass-packaging disposal, scenarios of Swiss waste glass-packaging are assessed from a life cycle perspective. The scenarios consist in schemes for the disposal of the total amount of Swiss waste glass-packaging, i.e., different combinations of recycling and downcycling in Switzerland or abroad developed in Part I, Meylan et al. (2013). In this article (Part II), the disposal schemes are assessed with respect to eco-efficiency, an indicator that combines total environmental impacts and gross value added in Switzerland. Results show that no policy alternative guarantees environmental impact reductions and gross value added gains under all developments of exogenous constraints. Downcycling to foam glass in Switzerland is not only an environmentally sound disposal option, but it also buffers gross value added losses in case domestic recycling (and thus glass-packaging production in Switzerland) ceases in the future. The substitution of products based on raw materials other than Swiss cullet is the main responsible for change in environmental and economic impacts. Hence, an eco-efficiency maximizing policy should consider the products of disposal schemes. The combination of scenario analysis and eco-efficiency assessment as presented in this paper can be applied to other contexts (i.e., countries, waste fractions).  相似文献   

20.
Due to the lack of appropriate policies in the last decades, 60% of Brazilian cities still dump their waste in non-regulated landfills (the remaining ones dump their trash in regulated landfills), which represent a serious environmental and social problem. The key objective of this study is to compare, from a techno-economic and environmental point of view, different alternatives to the energy recovery from the Municipal Solid Waste (MSW) generated in Brazilian cities. The environmental analysis was carried out using current data collected in Betim, a 450,000 inhabitants city that currently produces 200 tonnes of MSW/day. Four scenarios were designed, whose environmental behaviour were studied applying the Life Cycle Assessment (LCA) methodology, in accordance with the ISO 14040 and ISO 14044 standards. The results show the landfill systems as the worst waste management option and that a significant environmental savings is achieved when a wasted energy recovery is done. The best option, which presented the best performance based on considered indicators, is the direct combustion of waste as fuel for electricity generation. The study also includes a techno-economical evaluation of the options, using a developed computer simulation tool. The economic indicators of an MSW energy recovery project were calculated. The selected methodology allows to calculate the energy content of the MSW and the CH4 generated by the landfill, the costs and incomes associated with the energy recovery, the sales of electricity and carbon credits from the Clean Development Mechanism (CDM). The studies were based on urban centres of 100,000, 500,000 and 1,000,000 inhabitants, using the MSW characteristics of the metropolitan region of Belo Horizonte. Two alternatives to recovering waste energy were analyzed: a landfill that used landfill biogas to generate electricity through generator modules and a Waste-to-Energy (WtE) facility also with electricity generation. The results show that power generation projects using landfill biogas in Brazil strongly depend on the existence of a market for emissions reduction credits. The WtE plant projects, due to its high installation, Operation and Maintenance (O&M) costs, are highly dependent on MSW treatment fees. And they still rely on an increase of three times the city taxes to become attractive.  相似文献   

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