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711.
Life cycle analysis of several waste management scenarios for an Italian urban area was performed on the basis of different source segregation collection (SS) intensities from 0% up to 52%. Source segregated waste was recycled and or/recovered by composting. Residual waste management options were by landfilling, incineration with energy recovery or solid recovered fuel (SRF) production to substitute for coal. The increase in fuel and materials consumption due to increase in SS had negligible influence on the environmental impact of the system. Recycling operations such as incineration and SRF were always advantageous for impact reduction. There was lower impact for an SS of 52% even though the difference with the SS intensity of 35% was quite limited, about 15%. In all the configurations analyzed, the best environmental performance was achieved for the management system producing SRF by the biodrying process. 相似文献
712.
Water supply and wastewater services incur a large amount of energy and GHG emissions. It is therefore imperative to understand the link between water and energy as their availability and demand are closely interrelated. This paper presents a literature review and assessment of knowledge gaps related to water–energy–greenhouse gas (GHG) nexus studies in an urban context from an ‘energy for water’ perspective. The review comprehensively surveyed various studies undertaken in various regions of the world and focusing on individual or multiple subsystems of an urban water system. The paper also analyses the energy intensity of decentralized water systems and various water end-uses together with the major tools and models used. A major gap identified from this review is the lack of a holistic and systematic framework to capture the dynamics of multiple water–energy–GHG linkages in an integrated urban water system where centralized and decentralized water systems are combined to meet increased water demand. Other knowledge gaps identified are the absence of studies, peer reviewed papers, data and information on water–energy interactions while adopting a ‘fit for purpose water strategy’ for water supply. Finally, based on this review, we propose a water–energy nexus framework to investigate ‘fit-for-purpose’ water strategy. 相似文献
713.
The concept of integrated water management is uncommon in urban areas, unless there is a shortage of supply and severe conflicts among the users competing for limited water resources. Further, problem of water management in urban areas will aggravate due to uncertain climatic events. Therefore, an Integrated Urban Water Management Model considering Climate Change (IUWMCC) has been presented which is suitable for optimum allocation of water from multiple sources to satisfy the demands of different users under different climate change scenarios. Effect of climate change has been incorporated in non-linear mathematical model of resource allocation in term of climate change factors. These factors have been developed using runoff responses corresponding to base and future scenario of climate. Future scenarios have been simulated using stochastic weather generator (LARS-WG) for different IPCC climate change scenarios i.e. A1B, A2 and B1. Further, application of model has been demonstrated for a realistic water supply system of Ajmer urban fringe (India). Developed model is capable in developing adaptation strategies for optimum water resources planning and utilization in urban areas under different climate change scenarios. 相似文献
714.
根据城镇污水处理厂运行情况和城市供排水平衡分析提出一种简化的城镇居民生活污染源产排污总量核算的思路与方法,并以滇池流域为例核算了2010年滇池流域城镇居民生活主要污染物产生与排放总量。 相似文献
715.
基于生态系统服务价值的京津冀城市群湿地主导服务功能研究 总被引:4,自引:0,他引:4
湿地是地球三大生态系统之一,在气候调节、水资源供给、净化环境等方面具有重要的价值和作用。基于1990-2015年6期土地生态遥感解译数据和社会经济数据,通过修正生态系统服务价值当量因子和计算湿地价值的内外部贡献率,利用GIS定量研究了京津冀城市群及各个城市25年间不同湿地类型、不同功能生态系统服务价值的变化,并基于此进行功能定位。结果表明:(1)京津冀城市群湿地的生态系统服务价值呈现先上升后波动下降的趋势,2015年湿地价值较1990年上升了29.3亿元,主要是由于河渠、水库坑塘价值的增加,以及水文调节、水资源供给价值的增加;(2)京津冀城市群的13个城市中,天津市生态系统服务价值最高,且东部沿海区域湿地价值有增加趋势,南部内陆城市不仅湿地面积少且价值逐年下降;(3)水文调节、水资源供给和净化环境是京津冀城市群大部分城市湿地的主导功能,而河渠、水库坑塘、滩地则是提供服务功能的主要湿地类型。生态系统服务价值的减少与增加都与人类活动密切相关,因此了解湿地价值的变化趋势及变化原因,明确湿地的功能定位,不仅可以增强人们对湿地生态的保护意识,同时也为未来京津冀地区湿地的修复、恢复及可持续利用提供科学依据。 相似文献
716.
浅层淹水条件下不同施肥处理对黑土温室气体排放的影响 总被引:1,自引:0,他引:1
以东北黑土区长期耕作土壤为对象,通过室内培养试验研究了浅层淹水条件下不同施肥处理对黑土温室气体排放的影响.结果表明,浅层淹水条件下,与不施肥对照处理相比,单施氮肥处理对土壤CO2排放没有显著影响,氮肥配施猪粪或者秸秆则显著促进了CO2的排放,使得CO2排放速率提高了一个数量级,氮肥配施秸秆处理的CO2排放量最高.浅层淹水条件下,与不施肥对照处理相比,施用氮肥显著促进了土壤N2O的排放.而与单施氮肥处理相比,氮肥配施猪粪和秸秆则显著抑制了N2O的排放,表现为土壤对N2O的微量吸收,氮肥配施秸秆处理的N2O吸收量相对较高.浅层淹水条件下施用氮肥抑制了土壤CH4的排放,而与单施氮肥处理相比,氮肥配施猪粪或者秸秆则促进了土壤CH4的排放. 相似文献
717.
718.
Emergy analysis of the urban metabolism of Beijing 总被引:3,自引:0,他引:3
Cities can be modeled as if they were superorganisms with a range of metabolic processes. Research on this urban metabolism can contribute to solving urban environmental problems by revealing details of the metabolic throughput of the system. A key issue is how to find a common basis for measuring the environmental and economic values. By providing a single unified unit, emergy theory integrates the natural and socioeconomic systems and thoroughly evaluates a system's metabolism. We analyzed Beijing's urban metabolic system using emergy synthesis to evaluate its environmental resources, economy, and environmental and economic relations with the regions outside the city during 14 years of development. We compared Beijing's emergy indices with those of five other Chinese cities and of China as a whole to assess Beijing's relative development status. These indices are the emergy self-support ratio (metabolic dependence), the environmental load ratio (metabolic loading), empower density (metabolic pressure), emergy used per person (metabolic intensity per capita), and the monetary equivalent of emergy (emdollars; metabolic intensity). Based on our emergy analysis, Beijing's socioeconomic system is not self-sufficient, and depends greatly on external environmental resources. Its GDP is supported by a high percentage of emergy purchased from outside the city. During the study period, Beijing's urban system showed an increasing dependence on external resources for its economic development. Beijing's loading and pressure on the ecological environment is continuously increasing, accompanied by continuously increasing human emergy consumption. In the future, it will become increasingly necessary to improve Beijing's metabolic efficiency. 相似文献
719.
M.M. JiangB. Chen 《Ecological modelling》2011,222(13):2149-2165
This paper presented a thermodynamic synthesis that involved resource accounting, evaluation and modeling of urban ecosystems based on embodied cosmic exergy (EcE), which redefined embodied exergy with the cosmic microwave background radiation (CMBR) as the reference for solar exergy. In a case study of the Beijing urban ecosystem, the major resources supporting the urban ecosystem, both from free natural resources and from the economy, were accounted for, analyzed and evaluated in the same units, Cosmic Joules (Jc). These indicators revealed the current performance of the Beijing urban ecosystem by considering five aspects of the system: EcE sources, EcE intensity, EcE welfare, environmental impacts and economic efficiency. Moreover, through the combination of the EcE synthesis with a systems dynamics, this research constructed an embodied cosmic exergy-based urban system model (EESM) using Beijing as an example of urban development. The results show that the 10 years from 2010 to 2020 will be very critical for the sustainable development of Beijing because many key factors, such as water resources, wastes and urban assets, might be confronted with great changes during this period. These changes will inevitably transform the urban system not only in its external circumstances but also in its inner structure and may lead to serious consequences. Of all the necessary resources, the most sensitive factor is water supply. 相似文献
720.