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321.
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Petrochemical enterprises have become a major source of global greenhouse gas (GHG) emissions. Yet, due to the unavailability of basic data, there is still a lack of case studies to quantify GHG emissions and provide petrochemical enterprises with guidelines for implementing energy conservation and emission reduction strategies. Therefore, this study conducted a life cycle assessment (LCA) analysis to estimate the GHG emissions of four typical petrochemical enterprises in China, using first-hand data, to determine possible emission reduction measures. The analytical data revealed that Dushanzi Petrochemical (DSP) has the highest GHG emission intensity (1.17 tons CO2e/ton), followed by Urumqi Petrochemical (UP) (1.08 tons CO2e/ton), Dalian Petrochemical (DLP) (average 0.58 tons CO2e/ton) and Karamay Petrochemical (KP) (average 0.50 tons CO2e/ton) over the whole life cycle. At the same time, GHG emissions during fossil fuel combustion were the largest contributor to the whole life cycle, accounting for about 77.31%–94.27% of the total emissions. In the fossil-fuel combustion phase, DSP had the highest unit GHG emissions (1.20 tons CO2e), followed by UP (0.89 tons CO2e). In the industrial production phase, DLP had the highest unit GHG emissions (average 0.13 tons CO2e/ton), followed by UP (0.10 tons CO2e/ton). During the torch burning phase, torch burning under accident conditions was the main source of GHG emissions. It is worth noting that the CO2 recovery stage has "negative value," indicating that it will bring some environmental benefits. Further scenario analysis shows that effective policies and advanced technologies can further reduce GHG emissions. 相似文献
323.
In the present article, the thermal treatment of digested sewage sludge generated in the Swiss region of Zürich is modeled and optimized from an environmental perspective. The optimization problem is solved using a multi-objective mixed-integer linear program that combines material flow analysis, process models, life cycle assessment (LCA), and mathematical optimization techniques. The treatment options include co-incineration in municipal solid waste incineration, co-processing in cement production, and mono-incineration with the prospect of phosphorus recovery. The model is optimized according to six environmental objectives. Five of the six single-objective optimal solutions involve splits over the treatment options. The results reflect the available treatment capacities and other constraints, aspects rarely considered in conventional LCA studies. Co-processing in cement production is used to the maximum extent possible when minimizing impacts on climate change, human toxicity, fossil resource depletion, and fully aggregated impacts (ReCiPe H/A), whereas mono-incineration with phosphorus recovery receives the bulk of the sludge when optimizing for ecotoxicity and mineral resource depletion. Four of the single-objective optimal solutions (minimization of fossil energy resource depletion and contribution to climate change, human toxicity, and fully aggregated impacts) outperform the reference case over the six impact categories considered, showing that the current situation can be improved in some environmental categories without compromising others. The results of the sensitivity analysis indicate that assumptions regarding the product systems displaced by recovered by-products are critical for the outcome of the optimization. Our approach identifies in all of the cases solutions in which significant environmental improvements can be attained. 相似文献
324.
The objective of the study is to compare different development scenarios of a black water source-separation sanitation system (BWS) that could be environmentally and economically more viable than a conventional system (CONV). Scenarios performance is evaluated using life cycle assessment and environmental life cycle costing. System boundaries include the processes related to the collection and treatment of wastewater and organic kitchen refuse collection and the recycling of by-product (digestate/sludge and biogas) produced in the treatment step. The BWS scenario that entails a vacuum toilet flow-volume reduction to 0.5 L/flush results in significantly higher performances than the ones of CONV for the climate change and resources indicators, while involving a significantly lower performance with regards to human health and a comparable cost. The BWS scenario based on digestate mass reduction with reverse osmosis and acidification prior to its transport to farmland achieves comparable performances to the ones of CONV for all indicators. The BWS scenario with digestate treatment by means of phosphorus precipitation (struvite) and nitritation–anammox reactors gives performances that are comparable to the ones of CONV for all indicators, with the exception of climate change, for which this scenario has a significantly lower performance if the electricity is produced by hydropower. When single-pathway scenarios are combined, the multi-pathway scenarios thus created can produce results that are significantly superior to the CONV result for the climate change, resources and human health indicators although the cost remains comparable. 相似文献
325.
Malika Ghazi Gaetana Quaranta Joelle Duplay Raja Hadjamor Mohamed Khodja Hamid Ait Amar Zoubir Kessaissia 《Resources, Conservation and Recycling》2011,55(12):1222-1231
The objective of this work is to assess the environmental impacts of the drilling mud system in Algeria's arid region. Water-based mud (WBM) and oil-based mud (OBM) are used during well drilling in Hassi Messaoud petroleum field, and have a considerable pollution potential particularly on the aquifer system which constitutes the single resource of drinking water in the Sahara. The Life-Cycle Assessment (LCA) approach is applied to evaluate the impacts of several drilling mud systems across all stages of their life cycle, e.g. use, treatment and disposal. Environmental impacts of five treatments scenarios corresponding to the drilling waste management applied in Hassi Messaoud are compared: reserve pit without treatment (burial option), secondary high centrifugation (vertical cuttings dryer), stabilisation/solidification online, stabilisation/solidification off line and thermal desorption. The impact assessment is carried on using the LCIA models of Impact 2002+ method in SIMAPRO7 software. This assessment identifies human toxicity and terrestrial eco-toxicity as the major impact categories in this specific arid context and quantifies the emissions contributions. The local environmental impact is the most important of the drilling mud life cycle and is mainly linked to emissions from reserve pits, treated cuttings, and drilling phase 16″ through the Turonian and Albian aquifer. The main contributing substances are aromatic hydrocarbons fraction and metals in particular barium, zinc, antimony, arsenic, and aluminium. Concerning the comparison of the treatment scenarios, it appears that stabilisation/solidification online is the best one; it has the lowest impact score in the two dominating categories because of the waste minimisation: mud storage avoided in the reserve pit. The second best scenario is the thermal desorption which obtains the lowest impact score in carcinogen effects due to hydrocarbons reduction (<1%) and avoided impacts of recovered oil. The toxic substances fate modeling will be improved by taking into account their site-specific impact. 相似文献
326.
S. Ulgiati M. Ascione S. BargigliF. Cherubini P.P. FranzeseM. Raugei S. VigliaA. Zucaro 《Ecological modelling》2011,222(1):176-189
Selected energy and material resource conversion systems are compared in this paper under an extended LCA point of view. A multi-method multi-scale assessment procedure is applied in order to generate consistent performance indicators based on the same set of input data, to ascertain the existence of constraints or crucial steps characterized by low conversion efficiency and to provide the basis for improvement patterns. Optimizing the performance of a given process requires that many different aspects are taken into account. Some of them, mostly of technical nature, relate to the local scale at which the process occurs. Other technological, economic and environmental aspects are likely to affect the dynamics of the larger space and time scales in which the process is embedded. These spatial and time scale effects require that a careful evaluation of the relation between the process and its surroundings is performed, so that hidden consequences and possible sources of inefficiency and impact are clearly identified. In this paper we analyse and compare selected electricity conversion systems, alternative fuels and biofuels, waste management strategies and finally the time evolution of an urban system, in order to show the importance of a multiple perspective point of view for the proper evaluation of a system's environmental and resource use performance. 相似文献
327.
Johannes Järemo Göran Bengtsson 《Ecological modelling》2011,222(3):485-492
The age specific patterns of reproduction and mortality dictated by the life history of an organism apply to potential invaders as well as resident species of an area, but whether certain life history traits are more invasive than others is an unresolved issue. We analyze a two-population system of an invading and a resident species and test the effects of age on the probability to invade when the organisms are iteroparous or semelparous. The life history characteristics of the populations are projected in Leslie matrices, and the probability that the invader exceeds different population sizes is calculated by Monte Carlo analysis. The simulations show that (a) the invasion probability of an iteroparous organism increases with age until the individuals introduced are mature for first reproduction, and then becomes independent of age; (b) the invasion probability is more age sensitive for iteroparous organisms with high juvenile mortality (Type III organisms) than for those with a lower (Type I); (c) invading semelparous organisms are most affected by competition from resident organisms; (d) variations in vital rates of semelparous residents have greater influence on the invasion probability of an iteroparous organism than variations in traits of the invader. 相似文献
328.
329.
都江堰市城区周边农田土壤重金属污染状况分析与评价 总被引:4,自引:1,他引:3
以都江堰城区周边农耕地为对象,按照国标方法对土壤样本中的Cr、Cu、Cd、Pb、Zn五种重金属元素含量进行测定。结果表明,部分样本中的Cd、Cu含量超过国家土壤环境质量二级标准。采用单因子污染指数和土壤综合污染指数评价方法,以国家土壤环境质量二级标准为评价标准,对研究区内Cr、Cu、Cd、Pb、Zn重金属的污染状况进行评价,评价结果显示,Cu、Cd为主要污染元素,污染指数处于轻、中度污染,Cr、Pb、Zn对土壤尚未构成污染关系,研究区土壤重金属总体污染程度较轻。 相似文献
330.
Currently the construction and demolition (C&D) waste collection system in Spain is managed in a decentralized manner by each sub-contracted company. This lack of comprehensive strategy for C&D waste management causes a confusing and sometimes individual attitude regarding the different measures for C&D waste. Therefore effective waste management should be enforced. Construction stakeholders have wide range of best practices in C&D waste management that can be implemented, so they need to be assessed for their effectiveness.The aim of this research study is to assist construction stakeholders in making a decision on C&D waste management. This paper carries out a survey conducted among the construction agents in order to evaluate the effectiveness of 20 best practice measures regarding C&D waste management, identifying the most suitable types of building constructions to implement these practices and also the advantages and drawbacks of their performance in a building construction project.Results of this study show that among the highly effective best practices are: the use of industrialized systems and the contract of suppliers managing the waste. In addition, distributing small containers in the work areas is also another high valued practice, although only 36% of respondents usually implement this measure in their works. 相似文献