共查询到19条相似文献,搜索用时 234 毫秒
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废弃混凝土处理过程的环境影响是辅助废弃混凝土管理决策的重要依据。采用生命周期评价方法,对废弃混凝土再生骨料利用、再生原料利用、基础填料利用和填埋四种方式的环境影响,进行了核算。其中,生命周期影响评价方法采用“中点法”计算生命周期环境影响状况,并通过社会支付意愿的概念将生命周期影响状况结果转化为以货币价值表示的单一环境影响分值。结果表明:在材料替代的前提下,废弃混凝土再生骨料利用的环境影响最低,最能体现废弃混凝土的资源价值。目前西宁市建筑垃圾填埋弃置的收费标准,不能弥补填埋造成的环境影响,亦不足以改善废弃混凝土的再生利用。 相似文献
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废弃水泥混凝土占用大量土地、增加成本、污染环境,资源化处理废弃混凝土已经成为环境保护和可持续发展的关键问题。本文基于"离子渗透沉积"原理,先后采用稀硫酸溶液、饱和Ca(OH)2溶液对废弃水泥混凝土再生骨料进行了处理,陈伏14天后,测试其压碎指标和24小时吸水率。同时采用场发射环境扫描电镜和压汞仪对比分析了处理前后对再生骨料表面砂浆层的微细观性能,并初步探讨了"离子渗透沉积"作用机理。试验结果表明,虽然处理后再生骨料的吸水率变化并不明显,但是孔隙率测试结果表明,处理后总孔隙率降低了50%以上,大害孔含量降低了70%,再生骨料的强度显著提高,压碎值从20.3%降低到16.1%。采用SEM可以观察到经过处理后再生骨料的孔洞被气硬性胶凝材料氢氧化钙、碳酸钙和石膏等晶体填充。本文为废弃水泥混凝土再生利用提供了一种新的方法。 相似文献
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研究废弃混凝土分离回收及应用技术,实现废弃混凝土相关组分的有效分离,为再生利用提供可靠的技术保证。通过对废弃混凝土破碎"、剥壳"和筛分等过程的处理,将废弃混凝土的粗骨料与集料进行有效"剥壳"分离,粗骨料的性能与天然骨料相当,而"剥壳"的细料磨成超细粉后,用于混凝土的掺合料,改善混凝土性能,为废弃混凝土再利用提供了新的有效途径。 相似文献
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废弃混凝土再生利用探讨 总被引:2,自引:0,他引:2
随着我国建筑业迅猛发展,我国每年产生的废弃混凝土的量巨大并呈逐年上升的趋势。该文探讨了废弃混凝土再生利用的途径,设计了适应我国目前发展现状的再生骨料的生产工艺流程,并从环境效益和社会效益方面对废弃混凝土再生利用以及其再生利用产生的经济效益方面进行了分析,文章的分析表明废弃混凝土的再生利用一方面可以减轻废弃混凝土对环境的污染,节省其作为垃圾排放的清运和处理费用,另一方面可以充分利用废弃混凝土这种可再生资源,保护自然资源和人类的生存环境,有利于实施可持续发展战略。本文的研究表明废弃混凝土的再生利用具有很好的环保效益、社会效益和经济效益。 相似文献
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废弃混凝土的再生利用对节约资源、保护环境具有重要的意义,结合再生混凝土研究的重点和难点问题,分析了不同再生骨料掺量和不同粉煤灰掺量下再生混凝土在硫酸盐腐蚀环境中的抗压强度降低情况,并利用SEM分析了再生混凝土界面特性. 相似文献
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分析目前废弃混凝土再生技术,优化混凝土再生工艺,提出提高再生材料和再生混凝土性能的方法。为提高再生材料性能和废弃混凝土利用水平,在原有再生技术基础上,提出将各类再生材料分别进一步强化处理的再生工艺。试验表明,此种再生工艺解决了目前存在的技术缺陷,在得到再生粗骨料、再生细骨料和再生磨细掺和料的同时,各种再生材料技术指标和再生混凝土使用性能得到提高,增加了再生材料的品种,使废弃混凝土得到全部利用。 相似文献
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Proper management and recycling of huge volumes of food waste is one of the challenges faced by Singapore. Semakau island — the only offshore landfill of the nation — only accepts inert, inorganic solid waste and therefore a large bulk of food waste is directed to incinerators. A remaining small percent is sent for recycling via anaerobic digestion (AD), followed by composting of the digestate material. This article investigates the environmental performance of four food waste conversion scenarios — based on a life cycle assessment perspective — taking into account air emissions, useful energy from the incinerators and AD process, as well as carbon dioxide mitigation from the compost products derived from the digestate material and a proposed aerobic composting system. The life cycle impact results were generated for global warming, acidification, eutrophication, photochemical oxidation and energy use. The total normalized results showed that a small-scale proposed aerobic composting system is more environmentally favorable than incinerators, but less ideal compared to the AD process. By making full use of the AD's Recycling Phase II process alone, the Singapore Green Plan's 2012 aim to increase the recycling of food waste to 30% can easily be achieved, along with reduced global warming impacts. 相似文献
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Evaluation of environmental burdens caused by changes of food waste management systems in Seoul, Korea 总被引:2,自引:0,他引:2
During the last decade, there have been remarkable changes in food waste management in Korea following a ban on direct landfilling. To evaluate the environmental impacts of food waste management systems, we examined individual treatment systems with the LCA approach -- landfill, incineration, composting, and feed manufacturing -- and estimated the change from 1997 to 2005. The efficient system was different in each impact category, but it was evaluated that landfill is the main contributor to human toxicity and global warming (based on fossil CO(2)). In contrast, due to the increase of food waste recycling, acidification, eutrophication, and fresh water aquatic ecotoxicity impact was increased. Especially, the high energy consumption and generated residue in recycling systems caused the large burdens in toxicity categories. 相似文献
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石义海 《四川建筑科学研究》2009,35(6)
从废弃混凝土回收利用的必要性、天然骨料的紧缺程度等方面,对再生骨料的应用进行了定性分析.以定量分析对再生骨料的生产成本进行了具体的估算,对废弃混凝土回收利用分别进行了经济评价和环境评价分析,说明再生骨料应用具有很好的经济效益、社会效益、生态效益以及很好的市场应用前景,且符合国家产业政策. 相似文献
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随着城镇建设的快速发展,建筑垃圾剧增,对环境和社会的影响越加严重,建筑垃圾的减量化、资源化和再利用成为建筑业可持续发展亟待解决的问题。免烧免蒸砖是一种替代传统粘土实心砖的新型墙体材料,有利于节能、节地、利废,促进循环经济发展,具有良好的经济效益和社会效益。文章通过对建筑垃圾制免烧免蒸砖生产工艺的调查,系统分析了生产过程的各项环境排放因素,并运用生命周期评价理论和方法,对其生产过程的环境影响进行定量研究和综合测算。针对建筑垃圾制免烧免蒸砖的生产过程中主要环境影响因素,包括温室气体和粉尘的排放等,提出了改进建议。 相似文献
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Life cycle assessment of municipal solid waste management with regard to greenhouse gas emissions: Case study of Tianjin, China 总被引:5,自引:0,他引:5
Wei Zhao Ester van der Voet Gjalt Huppes 《The Science of the total environment》2009,407(5):1517-10314
The environmental impacts of municipal solid waste (MSW) management have been highlighted in China, due to the continually increasing amount of MSW being generated and the limited capacity of waste treatment facilities. Of particular interest is greenhouse gas (GHG) mitigation, aided by the Kyoto Mechanisms. China is an important case study for this global issue; however, an analysis of the entire life cycle of MSW management on GHG emissions is not available for China. This study evaluates the current and possible patterns of MSW management with regard to GHG emissions, using life cycle assessment (LCA), based on the Tianjin case. We assess the baseline scenario, reflecting the existing MSW management system, as well as a set of alternative scenarios, five exploring waste treatment technology innovations and one exploring integrated MSW management, to quantitatively predict potentials of GHG mitigation for Tianjin. Additionally, a sensitivity analysis is used to investigate the influence of landfill gas (LFG) collection efficiency, recycling rate and methodological choice, especially allocation, on the outcomes. The results show GHG emissions from Tianjin's MSW management system amount to 467.34 Mg CO2 eq. per year, based on the treatment of MSW collected in the central districts in 2006, and the key issue is LFG released. The integrated MSW management scenario, combining different improvement options, shows the highest GHG mitigation potential. Given the limited financial support and the current waste management practice in Tianjin, LFG utilization scenario would be the preferred choice. The sensitivity analysis of recycling rate shows an approximately linear relation of inverse proportion between recycling rate and total GHG emissions. Kitchen waste composting makes a considerable contribution to total GHG emissions reduction. Allocation choices result in differences in total quantitative outcomes, but preference orders and contributions analysis are found to be robust, suggesting LCA can support decision making. 相似文献