生命周期分析(LCA)的技术框架

ISO14040标准将LCA的实施步骤分为目的与范围的确定、清单分析、影响评价和结果解释四个阶段。a.目的和范围的确定:为开展LCA研究提供了一个初步计划。它说明开展LCA的目的和意图、研究结果的可能应用领域,确定LCA的研究范围,保证研究的广度、深度与要求的目标一致。b.清单分析:量化和评价所研究的产品、工艺或活动整个生命周期阶段资源和能量使用以及环境释放的过程。c.生命周期影响评价:为可选阶段。将清单数据进一步与环境影响联系起来,让非专业的环境管理决策者更容易理解。一般将影响评价定为一个“三步走”的模型,即分类、特征化和加权。d.解释:根据规定的目的和范围,综合考虑清单分析和影响评价的发现,从而形成结论并提出建议。如果仅仅是生命周期清单研究,则只考虑清单分析的结果。生命周期分析(LCA)的技术框架     

生命周期评价方法研究综述——兼论混合生命周期评价的发展与应用

生命周期评价(Life cycle assessment, LCA)随着其评价对象不断复杂化、系统化,逐渐发展出包含基于清单分析的过程生命周期评价(Process-based LCA, PLCA)、投入产出的生命周期评价(Economic input-output LCA, EIO-LCA)和混合生命周期评价(Hybrid LCA, HLCA)三种方法。论文简述了各类LCA方法的发展过程和特征,并结合实例分析了各自的优势与不足。结果认为:自下而上的PLCA方法针对性较好,其评价结果较为详细,但由于主观边界设定,核算结果存在无法避免的截断误差;自上而下的EIO-LCA方法采用投入产出表进行评价,边界为整个国民经济系统,但存在部门聚合、数据滞后等问题;HLCA结合PLCA与EIO-LCA两种方法,既保持了结果的精准性,又消除了截断误差。研究最后总结并提出未来HLCA的发展方向,以期为LCA方法的进一步发展提供参考。     

动态生命周期评价的研究与应用现状

生命周期评价（LCA）在理论和实际应用中存在一些局限性,包括清单和评价方法缺乏时间维度和空间维度,主要表现为缺乏对产品能源系统随时间变化的考虑,使用静态的过时的清单数据而非基于时间的动态生命周期清单数据,以及影响评价方面缺乏动态特征因子的选择和计算方法.动态生命周期评价（DLCA）是针对工业和环境系统的时间和空间变化的动态建模过程的评价方法,可大大提高传统生命周期评价的科学性和准确性.本文从3个方面对动态生命周期评价方法进行总结和评述,即将时间信息作为不确定因素的动态建模分析;生产过程或污染物排放的实时数据的获取;基于时间分化的动态特征因子的影响评价方法.通过目前的动态生命周期评价的研究现状来看,其方法框架并不统一,另外缺乏科学的时间分化的LCI计算的数学模型和软件以及生命周期影响评价的建模解决方案.因此,本文对DLCA未来的发展进行展望,以期为LCA方法的研究、应用、发展和完善提供更多的支持.     

危险废物处理处置技术评价方法研究

在对不同危险废物处理处置技术评价方法适用性进行分析的基础上,对危险废物处理处置技术评价方法进行了系统研究.结果发现专家评价法和环境技术评价(EnTA)法以定性评价为主,简单易行,应用范围广泛;生命周期评价(LCA)法以定量为主,但由于数据采集困难,目前在应用上还面临很多困难;层次分析(AHP)法把定性与定量评价融合得比较好,对于解决危险废物处理处置技术的选择问题行之有效.     

钢渣处理技术的环境性能比较

随着钢铁工业的快速发展,大量钢渣弃置堆积,不仅成为环境污染源,而且占用大量的土地。目前钢渣处理技术较多,其中主要的处理方法有冷弃法、热闷法、热泼法、浅盘法、水淬法、风淬法等。本研究采用生命周期评价方法,对主要钢渣处理技术进行评估,定义了生命周期评估边界和清单指标,建立了清单计算模型,得到了不同钢渣处理技术的生命周期清单。为了提高结果的可信性,对模型进行了不确定性分析。结果表明滚筒法和风淬法的环境性能较好,是值得推广的钢渣处理技术。     

综合产品环境审计工具:生命周期清单分析

生命周期清单分析是 ISO 14000环境管理系列标准内容之一 ,是定量评价产品生命周期全过程 (从原材料采掘到最终处理 )环境负荷的重要工具 ,也是实施产品全过程环境管理的重要审计工具 .系统地论述了生命周期清单分析的实施步骤、方法和相关的概念 .     

中国生命周期参考数据库的建立方法与基础模型

缺乏完善的本地化LCA(Life Cycle Assessment)数据库是国内广泛开展LCA研究与应用的主要障碍.本文总结提出了建立中国生命周期参考数据库(Chinese Reference Life Cycle Database,CLCD)的基本方法,包括环境影响类型与物质名录的选择、单元过程清单数据的收集与审核、生命周期清单数据的建模与计算、CLCD数据库的建立等4个方面.按照上述方法,以电力、煤炭、燃油、运输等基础性产品为核心,初步建立了可扩展的中国基础工业系统的生命周期模型,收集了单元过程的全国平均清单数据,通过模型计算获得了这些基础性产品的生命周期清单数据,从而得到了CLCD基础数据库,为下一步扩展为更完善的CLCD数据库提供了方法与模型基础.     

垃圾热化学转化利用过程中碳排放的两种计算方法

为了明确城市生活垃圾焚烧和热解两种热化学方式处理过程中温室气体的排放量(简称"碳排放"或GHG),分别采用生命周期评价方法(LCA)和政府间气候变化专门委员会(IPCC)制定的2006国家温室气体排放清单指南(简称"IPCC2006指南")进行了核算,并计算了两种垃圾热化学处理方式相对于填埋处理的GHG减排量.结果表明,两种核算方法计算所得的不同垃圾处理方式的碳排放趋势基本一致,但基于IPCC2006指南计算出的GHG减排量高于LCA方法的计算结果.相对填埋处理而言,焚烧处理的GHG减排量从LCA法的597～660kg(以CO2当量计,下同)提高到IPCC2006指南法的648～747kg;垃圾热解发电的GHG减排量从LCA法的535kg提高到IPCC2006指南法的589kg.同时,对这两种核算方法的特点及在我国的适用性进行了分析,研究认为LCA法和IPCC2006指南可以结合使用以促进我国GHG核算机制的完善.     

生命周期评价在清洁生产领域的应用前景

生命周期评价(LCA)作为一种产品环境特征分析和决策支持工具,技术上已经日趋成熟,并在国际社会得到较广泛的应用.由于它也同时是一种有效的清洁生产工具,因而可以在我国清洁生产审计、产品生态设计、废物管理、生态工业等方面发挥应有的作用.目前应尽快引进和消化吸收国际上先进的LCA方法,建立符合中国国情的LCA方法学体系和数据支撑体系,并在此基础上开展各个领域、各种形式的应用研究与示范.      

基于LCA方法的水泥企业清洁生产审核

水泥行业是典型的高能耗、高污染的工业,其快速发展带来了严重的资源、能源、环境等问题.因此,本文选择生命周期评价方法(LCA)作为清洁生产审核工具,对大连某水泥企业进行了清洁生产审核.本文在调研水泥工艺及现状的基础上,运用生命周期评价方法对水泥生产过程中原料开采、运输、生料制备、煤粉制备、熟料煅烧及水泥粉磨阶段进行清单分析与建模.采用了生命周期评价软件Gabi4进行清单计算与分析,评价模型为CML2001Dec07特征化模型.在整个水泥生产过程中考虑了全球变暖,人体毒性,环境酸化等环境影响类型,得出整个生命周期中石灰石和煤炭的资源能源耗竭潜值和资源消耗量最大,而环境排放影响中熟料煅烧阶段对各个类型的环境影响远远高于其他几个阶段,同时熟料煅烧过程中排放的二氧化碳等温室气体的影响最严重.最终根据评价分析结果确定清洁生产审核重点并提出了清洁生产方案,并且在清洁生产方案中选择其中最重要的余热发电方案,进行余热发电清洁生产方案前后环境影响比较和清洁生产方案量化分析.     

Development of weighting factors in the context of LCIA

A new method is proposed for the identification of environmental impact category weights using a panel approach and a MultiCriteria Decision Aid (MCDA) for use within the weighting step in Life Cycle Impact Assessment (LCIA). Seven environmental criteria were assessed by panellists and weights were obtained. The weighting factors of 10 impact categories were calculated according to a four-step procedure: (1) criteria definition; (2) scoring of each impact category (scale of 1–100, 100 causing the most damage) according to seven environmental criteria (human health, ecosystem health, resource consumption as well as scale, duration, reversibility and “distance-to-target”) by a panel of Canadian citizens; (3) assessment of each criterion's importance using a “resistance to change” approach; and (4) criteria aggregation (through MCDA) which allowed the calculation of a final weighting score for each impact category. The greatest advantage of this procedure is the ease with which it can be implemented in a Life Cycle Assessment (LCA) study whatever the LCIA method is used. Integrating weighting factors specific to the Canadian environmental context into a site-dependant LCIA method will contribute to the progress of LCA in Canada.     

Method for assessing impacts on life support functions (LSF) related to the use of ‘fertile land’ in Life Cycle Assessment (LCA)

Degradation of soil quality is a major concern due to the scarcity of fertile land, and needs to be properly addressed in the environmental assessment of agro-forestry systems. This paper addresses the main issues arising in assessing the impacts of fertile land use on “Life Support Functions” in Life Cycle Assessment (LCA). These issues include the assessment of occupation and transformation impacts, the references against which such impacts should be measured, and the concept of natural relaxation versus backup technology for recovery from the impacts. The alternative (or reference) situation is defined using the concept of consequential LCA, which facilitates clarification of the allocation issues arising due to successive land uses. This paper presents soil organic matter (SOM) as a robust indicator for soil quality; even though it does not fully consider all aspects of soil functioning, SOM has been often recognised as the best stand-alone indicator for soil quality. Impacts on biodiversity are not included in this indicator and should be assessed in parallel. Alternative data sources for practical implementation of the method are suggested in a hierarchical way, including locally specific data sets describing changes in SOM; mechanistic models for the prediction of SOM evolution; and general data sources for simplified analyses. Thanks to its flexibility in data collection the method is applicable to any agricultural or forestry LCA to fill an important gap in Life Cycle Impact Assessment (LCIA) of land use.     

Eco-toxicological impact of “metals” on the aquatic and terrestrial ecosystem: A comparison between eight different methodologies for Life Cycle Impact Assessment (LCIA)

The assessment of eco-toxicological impacts related to the emission of contaminants into the environment has peculiar characteristics in the context of Life Cycle Assessment (LCA), and many different Life Cycle Impact Assessment (LCIA) methodologies can be used. However, previous studies recognized the presence of high uncertainties in the process, in particular when the analysis focuses on metal emissions. Metals are diverse inorganic substances relevant for their characteristic environmental chemistry, their high persistency into the environment and their toxicity at even low environmental concentrations. This study aims at expanding the discussion about how, and how differently, various methods for LCIA are estimating the impacts related to metals emissions, with a focus on eco-toxicological impacts. A comparison between eight different LCIA methods is presented in relative terms, using a contribution analysis at two levels: general and specific. Results show that there is a poor agreement between methods in the determination of the total eco-toxic impact attributable to metals, and in defining which metal provokes the highest eco-toxic impact per unitary emission. Furthermore, the characterization phase is critical in determining the disagreement between methods. However, some similarities were found: there is the tendency in most methods to associate the largest share of the total eco-toxicological impacts to metals. Theoretical and practical differences between methods are discussed and suggestions for the choice of the proper, case-specific, LCIA method are provided.     

基于生命周期思想的透水铺装资源环境影响评价述评

透水铺装作为典型的海绵城市设施,具有城市雨水径流减排、水质净化等多种环境效益,但在材料制备、施工、维护管理过程中相对于传统铺装资源能源消耗有所增加,亟须应用生命周期评价这一系统分析方法,开展透水铺装的资源环境效益的综合评估。通过文献述评,总结了生命周期评价方法应用于透水铺装评估的现状与面临的挑战,并提出了相应对策:将运行维护阶段纳入评价系统边界,有助于提升透水铺装资源环境评价的全面性;针对生命周期评价结果难以指导工程设计的问题,建议将生命周期评价与建筑信息模型相结合,优化透水铺装的绿色设计;针对透水效应动态变化等生命周期环境影响评价方法问题,建议将水文模型引入整体评估方法。通过上述角度的提升,生命周期评价方法有望为透水铺装的政策制定、规划设计、施工养护等全过程提供参考数据与优化方案,助力海绵城市建设乃至城市生态系统的良性发展。     

环境技术验证评价体系研究与案例应用

目前,以政府为主导的环境技术评价体系已不能满足新形势下对创新环境技术评价的不同需求,为了适应我国环境技术水平的迅速发展和环境保护的要求,迫切需要建立起一个有效的环境技术评价体系.在对加拿大、美国等推行的环境技术验证(ETV)制度比较研究的基础上,提出了国际等效且符合我国国情的环境技术验证评价程序和测试参数体系,基本流程分为验证申请、验证准备、验证测试、验证评价、验证结果发布5个阶段,研究了测试参数、测试周期、采样频率的设计原则及方法.并以水蚯蚓原位消解污泥技术为例开展应用研究,对该技术的环境保护效果、环境影响以及从其他环境观点出发的重要性能进行了测试和分析.结果显示,通过对环境效果参数、维护管理参数和运行工艺参数的评价,能够客观有效地反映处理技术的真实性能.     

生命周期评价在企业环境管理中的应用

环境管理对于企业的可持续发展起着决定性的作用,生命周期评价作为面向产品系统的新型环境管理工具越来越多地被企业所采用。文章结合中国企业环境管理实际,对所采用的环境管理工具做了分类,详述了生命周期评价的具体应用以及优势。对生命周期评价在未来企业环境管理中的重要作用做了展望。     

Life cycle assessment of mine tailings management in Canada

The effective management of mine tailings involves the control of several environmental impacts and legal requirements. Six tailings site management and closure scenarios were developed for a copper zinc underground mine located in Quebec (Canada) and compared using life cycle assessment (LCA). Two options are considered for the mine operation: tailings can be sent to the tailings disposal area where they are submerged or they can be partly used for backfilling. For each of these two operation options, three alternatives are presented for mine closure: (a) submerged tailings, (b) partial desulphurization with a cover of desulphurized material and (c) a cover with capillary barrier effects (CCBE) made of natural soils followed by revegetation. The goals of the study were to draw the inventory of these management scenarios from the development to the post-closure phase, to assess and compare their environmental impacts and to determine the importance of the land-use impact category. The potential impacts for each scenario were evaluated using the IMPACT 2002+ LCIA method. The results of the performed LCA indicate that for mine development and operation, scenarios where tailings are partly used as backfill for underground stopes appear to lead to larger impacts in 11 of the 14 midpoint categories since the backfill plant operation consumes a greater amount of material and energy. For a site closure period of 2 years, the CCBE option creates the greatest impacts, since it requires much more effort than the other techniques. The results for the post-closure phase have been analysed separately since they have a larger uncertainty. They appear to modify the comparative assessment results. The various results presented in the paper show the importance of taking land-use impacts into account.     

Influence of impact assessment methods in wastewater treatment LCA

Facing the increase of environmental concern in the water treatment field, stakeholders need reliable decision support tools to assess environmental performances of urban and industrial wastewater systems. To discuss how life cycle assessment (LCA) can be applied to wastewater treatment projects, such an assessment has been performed through a case study on a full-scale plant. Methodological issues that had to be dealt with are briefly exposed. Five life cycle impact assessment (LCIA) methods have been used: CML 2000, Eco Indicator 99, EDIP 96, EPS and Ecopoints 97. Consistent assessment between these methods has been obtained for greenhouse effect, resources depletion and acidification. Eutrophication is correctly estimated if one looks at the potential impact of a treatment scenario but not at the characterization of the eutrophication state of a specific receiving stream. Work is needed concerning human toxicity as large discrepancies are noticed between the impact assessment methods.     

Impacts of “metals” on human health: a comparison between nine different methodologies for Life Cycle Impact Assessment (LCIA)

This paper looks into the differences and uncertainties in determining the impact of “metals’” emissions on human health, in Life Cycle Impact Assessment (LCIA). Metals are diverse substances, with different properties and characteristics, considered important in LCIA because of their toxicity to humans and ecosystems. First, we defined a list of the most significant metals in terms of impacts on human health. This was done according to precise criteria accounting for both physical and toxic properties of the metals. Second, we performed an LCIA on different key processes using various existing LCIA methodologies and including also USEtox: the recently developed consensus-model for LCIA. Last, we compared the results in relative terms using a contribution analysis. The analysis showed poor or no agreement between the methods: the relative contribution of each metal and of the metals in total to the total impact on human health changes greatly according to the LCIA method used. These differences are due mainly to the number of metals included in each method and to the technique used to calculate the characterization factors. Results obtained with USEtox show no apparent correlation with results calculated with other methods. At present time USEtox is recommended as the best model for LCIA on human toxicity, but mainly because of the large consensus behind it, because its uncertainties regarding metals are still high. The study gives a good and simple overview regarding the way different methods address the impact assessment for metals, and helps in the interpretation of LCIA results for actual LCA studies where metal emissions are involved.     

Environmental management and life cycle approaches in the Mexican mining industry

Mexico ranks among the 11 major producer countries of minerals worldwide; its open pit and underground systems are 500 years old. This paper presents an overview of the Mexican mining industry from technological development, historical and economic perspectives. The efforts made by mining companies to address issues of environmental management and sustainable development expressed in national and international frameworks, as well as the Mexican environmental regulatory framework for the mining sector, are analyzed. Since, among others, life cycle assessment (LCA) has been recognized as a key topic to promote sustainable development in the Latin American and Caribbean region, this paper also examines the application of LCA in mining. Two life cycle approaches are presented: a national life cycle inventory for base metals, and an integral life cycle model for the management of mining processes.