Using LCA to evaluate impacts and resources conservation potential of composting: A case study of the Asti District in Italy

Separate collection of municipal solid waste has overcome the 50% threshold in the Asti District in northern Italy, nearly one-third being composed of household and green organic waste. In order to address present and future solutions, it becomes therefore fundamental to assess the environmental performances of the current management of organic waste from separate collection. A from-gate-to-cradle life cycle assessment (LCA) model has been developed by expanding system boundaries, in order to carry out the assessment in the context of the whole waste management streamline. The environmental performances of an existing aerobic plant were made available, based on field measured data, by paying attention to the role and contribution of waste management subsystems. The need for actual and reliable data on materials and energy input, as well as gross and net gains from materials recovery, including benefits arising from use of compost in farming activities, was probably the major drawback that had to be faced. The study integrated the findings of different investigations from the literature with field measured data in order to obtain a more comprehensive framework representative of the area under study. The results may help public administrators to better understand the suitability of using LCA tools when dealing with solid waste management strategies.     

Environmental and economic analysis of management systems for biodegradable waste

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.     

生命周期评价在我国固体废物环境管理中的应用

生命周期评价是评价产品、工艺或活动（服务）整个生命周期阶段有关环境负荷,进而辨识和评价减少环境影响机会的一种非常有用的工具。将生命周期评价应用于固体废物环境管理,无疑对于我国建立科学化的固体废物环境管理模式具有十分重要的作用。本文对生命周期评价的定义、主要阶段、应用工具、特点进行了阐述,并对生命周期评价如何应用于我国固体废物环境管理进行了探讨。     

Methodological aspects of life cycle assessment of integrated solid waste management systems

Environmental life cycle assessment (LCA) developed rapidly during the 1990s and has reached a certain level of harmonisation and standardisation. LCA has mainly been developed for analysing material products, but can also be applied to services, e.g. treatment of a particular amount of solid waste. This paper discusses some methodological issues which come into focus when LCAs are applied to solid waste management systems. The following five issues are discussed. (1) Upstream and downstream system boundaries: where is the ‘cradle’ and where is the ‘grave’ in the analysed system? (2) Open-loop recycling allocation: besides taking care of a certain amount of solid waste, many treatment processes also provide additional functions, e.g. energy or materials which are recycled into other products. Two important questions which arise are if an allocation between the different functions should be made (and if so how), or if system boundaries should be expanded to include several functions. (3) Multi-input allocation: in waste treatment processes, different materials and products are usually mixed. In many applications there is a need to allocate environmental interventions from the treatment processes to the different input materials. The question is how this should be done. (4) Time: emissions from landfills will continue for a long time. An important issue to resolve is the length of time emissions from the landfill should be considered. (5) Life cycle impact assessment: are there any aspects of solid waste systems (e.g. the time horizon) that may require specific attention for the impact assessment element of an LCA? Although the discussion centres around LCA it is expected that many of these issues are also relevant for other types of systems analyses.     

A waste management planning based on substance flow analysis

The paper describes the results of a municipal solid waste management planning based on an extensive utilization of material and substance flow analysis, combined with the results of specific life cycle assessment studies. The mass flow rates of wastes and their main chemical elements were quantified with a view to providing scientific support to the decision-making process and to ensure that the technical inputs to this process are transparent and rigorous. The role of each waste management option (recycling chains, biological and thermal treatments), as well as that of different levels of household source separation and collection (SSC), was quantitatively determined. The plant requirements were consequently evaluated, by assessing the benefits afforded by the application of high quality SSC, biological treatment of the wet organic fraction, and thermal treatment of unsorted residual waste. Landfill volumes and greenhouse gas emissions are minimized, toxic organic materials are mineralized, heavy metals are concentrated in a small fraction of the total former solid waste volume, and the accumulation of atmophilic metals in the air pollution control residues allows new recycling schemes to be designed for metals. The results also highlight that the sustainability of very high levels of SSC is reduced by the large quantities of sorting and recycling residues, amounts of toxic substances in the recycled products, as well as logistic and economic difficulties of obtaining very high interception levels. The combination of material and substance flow analysis with an environmental assessment method such as life cycle assessment appears an attractive tool-box for comparing alternative waste management technologies and scenarios, and then to support waste management decisions on both strategic and operating levels.     

Identification and testing of potential key parameters in system analysis of municipal solid waste management

Life cycle assessment (LCA) and life cycle costing (LCC) are well-established methods used for many years in many countries for system analysis of waste management. According to standard LCA procedure the assessment should include improvement analysis, in many cases this is performed by simple sensitivity analyses. An obstacle to perform more thorough sensitivity analyses is that it is hard to distinguish input data important to the results, i.e. key parameters. This paper further elaborates sensitivity analyses performed in an environmental system analysis for a hypothetical Swedish municipality. In this paper, the method to identify and test input data that can be categorised as potential key parameters is described. The method and the results from computer simulations of the identified parameters are presented, and some conclusions are drawn regarding the robustness of the results for environmental impact from municipal solid waste management. The major conclusion is that the results are robust. Changes in results, when changing the preconditions, are often small and the changes observed do not lead to new conclusions; i.e., a change of ranking order between treatment options.     

以大数据驱动固体废物管理创新的思考

2015年7月,国务院印发《关于积极推进"互联网+"行动的指导意见》,鼓励利用物联网、大数据开展信息采集、数据分析、流向监测,跟踪废物流向,创新再生资源回收模式。我国固体废物种类多、数量大,部分废物具有一定的综合利用价值。从环境风险角度来看,需要关注固体废物生产、转移、利用、处置等多个环节,一直是环境管理的难点。但以大数据和云计算为代表的新技术为推动固体废物有效利用、提升环境风险防控能力提供了可能。文章介绍了新加坡利用大数据关联模型分析技术开展共生产业园区规划和建设,以及江苏省利用大数据和物联网技术开展危险废物转移动态监管的案例,分析了大数据应用在固体废物管理方面的优势和存在的挑战,为固体废物管理大数据建设提出了初步设想。未来固体废物大数据的建设应围绕《土壤污染防治行动计划》,首先要服务社会,实现数据共享和信息公开;其次要服务于日常管理,固体废物管理部门可以通过大数据应用辅助决策,落实简政放权,实现智慧管理;再次要服务于环境应急,通过对固体废物全生命周期的数据实时采集和动态分析,整合应急资源,服务应急救援。     

Alternative scenarios to meet the demands of sustainable waste management

This paper analyses different alternatives for solid waste management that can be implemented to enable the targets required by the European Landfill and Packaging and Packaging Waste Directives to be achieved in the Valencian Community, on the east coast of Spain. The methodology applied to evaluate the environmental performance of each alternative is Life Cycle Assessment (LCA). The analysis has been performed at two levels; first, the emissions accounted for in the inventory stage have been arranged into impact categories to obtain an indicator for each category; and secondly, the weighting of environmental data to a single unit has been applied. Despite quantitative differences between the results obtained with four alternative impact assessment methods, the same preference ranking has been established: scenarios with energy recovery (1v and 2v) achieve major improvements compared to baseline, with scenario 1v being better than 2v for all impact assessment methods except for the EPS'00 method, which obtains better results for scenario 2v. Sensitivity analysis has been used to test some of the assumptions used in the initial life cycle inventory model but none have a significant effect on the overall results. As a result, the best alternative to the existing waste management system can be identified.     

Assessing the “design paradox” with life cycle assessment: A case study of a municipal solid waste incineration plant

One of the most important processes in an integrated waste management system is incineration, which, among the different waste management disposal options still remains a critical waste treatment system. New dynamics and approaches have to be developed to embrace such a wide and complex topic, and better knowledge and assessment of incineration are strategically significant to define future environmental scenarios.Life cycle assessment (LCA), as a tool to optimise process-operating conditions and to support decision-making process, is often applied to investigate processes under design in various sectors, since choices made in the development phases can affect the future environmental profile. However, even if the greatest opportunity to improve a process from an environmental perspective is during the design phase, at the same time the knowledge is limited, in accordance with the so-called “design paradox”.Thus, in this context, this study used LCA methodology to quantitatively assess the extent to which the environmental impact of an incineration line reflects the environmental burdens perceived during the design phase. A comparative LCA was conducted at the design phase and under operating conditions at an Italian municipal solid waste incineration plant.The outcomes of the study indicated that for almost all of the categories analysed, the impacts associated with the process under design overestimated the impacts associated with the operating process, with the exception of climate change and water depletion. The results suggested that after the conduction of an LCA at the design phase of a process, an LCA of the operative conditions should be carried out to verify how much the over- or under-estimations affected the results.     

A mixed integer linear programming model for optimisation of organics management in an integrated solid waste system

In this paper, the authors propose a mixed integer linear programming model for designing an Integrated Solid Waste Management System (ISWMS) to meet specific economic goals. The model refers to a set of municipalities, known as ‘local basin’, which have to share a common waste management system. At the municipal level the model allows for an identification of the optimal collection service option; at the local basin level, the model provides the optimal waste flow appropriate to the collection service option of each municipality. The model has been applied to a full-scale case study of an area located in southeast Italy. A scenario analysis was carried out to investigate alternative municipal solid waste management options, which fundamentally differ in the organic flow mass rate to be either collected and composted or landfilled. Findings show that an increase in the cost of landfilling determines the optimal collection scenario and the configuration plants tend to recover higher rates of organics in separate collection and thus higher refuse derived fuel productions. The results obtained validate the application of the model in both the strategic planning and operational phases, by supporting public administrators at both municipality and local basin level in decision making and evaluation of technical and economic performances of ISWMSs.     

Life cycle assessment for reuse/recycling of donated waste textiles compared to use of virgin material: An UK energy saving perspective

In the UK, between 4 and 5% of the municipal solid waste stream is composed of clothes/textiles. Approximately 25% of this is recycled by companies such as the Salvation Army Trading Company Limited (SATCOL) who provide a collection and distribution infrastructure for ‘donated’ clothing and shoes. Textiles can be reused or undergo a processing stage and enter a recycling stream. Research was conducted in order to quantify the energy used by a reuse/recycling operation and whether this resulted in a net energy benefit. The energy footprint was quantified using a streamlined life cycle assessment (LCA), an LCA restricted in scope in order to target specific aspects of the footprint, in this case energy consumption. Taking into account extraction of resources, manufacture of materials, electricity generation, clothing collection, processing and distribution and final disposal of wastes it was demonstrated that for every kilogram of virgin cotton displaced by second hand clothing approximately 65 kWh is saved, and for every kilogram of polyester around 90 kWh is saved. Therefore, the reuse and recycling of the donated clothing results in a reduction in the environmental burden compared to purchasing new clothing made from virgin materials.     

An energetic life cycle assessment of C&D waste and container glass recycling in Cape Town,South Africa

This study presents the results of a comparative life cycle assessment (LCA) on the energy requirements and greenhouse gas (GHG) emission implications of recycling construction and demolition (C&D) rubble and container glass in Cape Town, South Africa. Cape Town is a medium sized city in a developing country with a growing population and a rising middle class, two factors that are resulting in increased generation of solid waste. The City is constrained in terms of landfill space and competing demands for municipal resources.The LCA assessment was based on locally gathered data, supplemented with ecoinvent life cycle inventory data modified to the local context. The results indicated that recycling container glass instead of landfilling can achieve an energy savings of 27% and a GHG emissions savings of 37%, with a net savings still being achieved even if collection practices are varied. The C&D waste results, however, showed net savings only for certain recycling strategies. Recycling C&D waste can avoid up to 90% of the energy and GHG emissions of landfilling when processed and reused onsite but, due to great dependence on haulage distances, a net reduction of energy use and GHG emissions could not be confidently discerned for offsite recycling. It was also found that recycling glass achieves significantly greater savings of energy and emissions than recycling an equivalent mass of C&D waste.The study demonstrated that LCA provides an important tool to inform decisions on supporting recycling activities where resources are limited. It also confirmed other researchers’ observations that strict adherence to the waste management hierarchy will not always result in the best environmental outcome, and that more nuanced analysis is required. The study found that the desirability of recycling from an energy and climate perspective cannot be predicted on the basis of whether such recycling conserves a non-renewable material. However, recycling that replaces a virgin product from an energy-intensive production process appears to be more robustly beneficial than recycling that replaces a product with little embodied energy. Particular caution is needed when applying the waste management hierarchy to the latter situations.     

全过程固体废物管理研究进展及其对我国相关管理的启示

当某种固态、半固态物质不再具有原有的价值，它就成了固体废物，并可能在产生、排放、收集、贮存、运输、利用、处理和处置过程的任何一个或多个环节产生对环境的污染危害。对固体废物进行全过程监督管理因而显得尤为重要。本文回顾了全过程固体废物管理实施方法，包括生命周期清单和生命周期评价方法，用于废物管理系统的模型，在固体废物产生量预测、收集系统最优化以及处理处置设施选址等步骤中，各自所用不同方法的进展，以及在一些较发达国家和地区的管理实例。最后讨论了这些进展对我国固体废物相关管理的启示。     

LCA: A decision support tool for environmental assessment of MSW management systems

Life cycle assessment (LCA) can be successfully applied to municipal solid waste (MSW) management systems to identify the overall environmental burdens and to assess the potential environmental impacts. In this study, two methods used for current MSW management in Phuket, a province of Thailand, landfilling (without energy recovery) and incineration (with energy recovery), are compared from both energy consumption and greenhouse gas emission points of view. The comparisons are based on a direct activity consideration and also a life cycle perspective. In both cases as well as for both parameters considered, incineration was found to be superior to landfilling. However, the performance of incineration was much better when a life cycle perspective was used. Also, landfilling reversed to be superior to incineration when methane recovery and electricity production were introduced. This study reveals that a complete picture of the environmental performance of MSW management systems is provided by using a life cycle perspective.     

Environmental and economic aspects of production and utilization of RDF as alternative fuel in cement plants: A case study of Metro Vancouver Waste Management

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.     

Life cycle assessment of EPS and CPB inserts: design considerations and end of life scenarios

Expanded polystyrene (EPS) and corrugated paperboard (CPB) are used in many industrial applications, such as containers, shock absorbers or simply as inserts. Both materials pose two different types of environmental problems. The first is the pollution and resource consumption that occur during the production of these materials; the second is the growing landfills that arise out of the excessive disposal of these packaging materials. Life cycle assessment or LCA will be introduced in this paper as a useful tool to compare the environmental performance of both EPS and CPB throughout their life cycle stages. This paper is divided into two main parts. The first part investigates the environmental impacts of the production of EPS and CPB from 'cradle-to-gate', comparing two inserts--both the original and proposed new designs. In the second part, LCA is applied to investigate various end-of-life cases for the same materials. The study will evaluate the environmental impacts of the present waste management practices in Singapore. Several 'what-if' cases are also discussed, including various percentages of landfilling and incineration. The SimaPro LCA Version 5.0 software's Eco-indicator 99 method is used to investigate the following five environmental impact categories: climate change, acidification/eutrophication, ecotoxicity, fossil fuels and respiratory inorganics.     

Current Levels and Management of Solid Wastes in Nigeria

Solid waste is of serious concern in developing countries because of its high rate of generation and the low‐end quality of its management. Inefficient handling of solid wastes may result in deterioration of environmental quality, but it can also result in loss of potential resources. This study reviews current solid waste generation and management in Nigeria and the need for an effective collection, recovery, and recycling policy. Our review is based on literature searches and personal field surveys. Observations showed that uncontrolled electronic waste (e‐waste), agricultural‐waste (agro‐waste), scrap metals, waste polymers, and waste from the transportation sector are prevalent in Nigeria. Recent collection rates were less than 50% of the total solid waste generated (i.e., approximately 40% was collected). With an effective collection system and appropriate policies, the abundance of solid waste in the country could present material recovery and recycling opportunities that would boost the economy and move Nigeria closer to sustainable resource management.     

Social and environmental injustices in solid waste management in sub-Saharan Africa: a study of Kinshasa,the Democratic Republic of Congo

This paper investigates social and environmental injustices in solid waste management in Kinshasa, the capital of the Democratic Republic of Congo. The urban poor in most parts of Kinshasa bear a huge encumbrance of the solid waste burden and face multiple challenges associated with poor management of solid waste. This situation has resulted in poor and unhealthy living conditions for the majority of the urban residents. The problem of solid waste management in Kinshasa has further been compounded by rapid urbanisation which has occurred in the face of poor urban governance, civil conflict and weak institutional set-up. The combination of these challenges has resulted in increased overcrowding, poor sanitary conditions, lack of water and an unprecedented accumulation of solid waste which have triggered a myriad of urban problems. The worst affected are the poor urban who reside in locations that receive little or no socio-economic services from the Kinshasa Municipal authority. Using secondary data collected through a desk study, this paper argues that the poor solid waste situation in Kinshasa is not only a health risk, but also presents issues of both social and environmental injustices. These issues are analysed within the context of evolving arguments that focus on the need to develop a pro-poor approach in solid waste management that may present an opportunity for achieving both social and environmental justice for the urban poor in Kinshasa.     

Transitions of municipal solid waste management. Part II: Hybrid life cycle assessment of Swiss glass-packaging disposal

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).     

Design and implementation study of a Permanent Selective Collection Program (PSCP) on a University campus in Brazil

The selective collection and recycling of municipal solid waste are presented as stages of an integrated program of solid waste management to minimize the environmental impact of the treatment and final disposal of solid waste. Therefore, this program aims to save natural resources, such as energy and raw materials, in the manufacture of new products and to conserve areas for sites, such as to minimize the use of existing landfill sites, and to minimize the need for new waste treatment sites. A university is composed of educational professionals aware of their societal responsibilities, and, therefore, they play a fundamental role in the management of the university's solid waste. This study presents the design and implementation of a Permanent Selective Collection Program (PSCP) at the Federal University of Itajubá (Universidade Federal de Itajubá, UNIFEI), Itajubá-MG, Brazil. The material requirements for initiating the PSCP have been identified, and an action plan for continuous program improvement, which is initially based on the collection of performance indicator data for the PSCP campus, has been developed. Finally, the data from the PSCP performance indicators and software from the United States Environmental Protection Agency, the Landfill Gas Generation Model (LandGEM) and the Waste Reduction Model (WARM), were used to evaluate the impact of implementing PSCP in terms of energy and the generation of greenhouse gases (GHG). The results were promising, showing that there has been an improvement, since the inception of PSCP in 2006, in separating materials for selective collection, even though paper (41.00 wt%), plastic (6.00 wt%) and organic matter (26.00 wt%) are still highly generated wastes. The WARM simulations for a scenario in which 90% of the waste is sent for recycling resulted in an economy of −7 tCO₂ or −74.91 GJ (on an energy basis). The LandGEM (USEPA) simulations estimated 1424.60 kWh of energy in the peak production year.