Life-cycle greenhouse gas emissions assessment and extended exergy accounting of a horizontal-flow constructed wetland for municipal wastewater treatment: A case study in Chile

The life-cycle greenhouse gaseous emissions and primary exergy resources consumption associated with a horizontal subsurface flow constructed wetland (HSSF) were investigated. The subject of study was a wetland for municipal wastewater treatment with a 700-person-equivalent capacity. The effects of two types of emergent aquatic macrophytes (Phragmites australis and Schoenoplectus californicus) and seasonality on greenhouse gas (GHG) gas emissions, the environmental remediation cost (ERC) and the specific environmental remediation cost (SERC) were assessed. The results indicate that GHG emissions per capita (12–22 kgCO2eq/p.e/yr) and primary exergy resources consumed (24–27 MJ/m³) for the HSSF are lower than those of a conventional wastewater treatment plant (67.9 kgCO2eq/p.e/yr and 96 MJ/m³). The SERC varied between 176 and 216 MJ/kg biological oxygen demand (BOD₅) removal, which should be further reduced by 20% for an improved BOD₅ removal efficiency above 90%. The low organic matter removal efficiency is associated with a high organic load and low bacterial development. Seasonality has a marked effect on the organic removal efficiency and the SERC, but the macrophyte species does not.     

基于扩展耗模型的可持续发展水平区域空间差异——以中国31个省市为数据源

将区域作为一个以人类生产和消费为中心的社会-经济-自然复合生态系统,构建了一种基于生物物理视角的生态热力学方法,从整体角度对区域的可持续发展水平进行定量评价。该方法囊括了维持复合生态系统运转过程中的自然资源投入、人力资源投入和环境污染损害成本投入等三种要素,完善了可持续发展评价以及绿色GDP核算中人力资源投入和环境成本的价值体现。然后以我国为例,核算了我国31个省市2006—2015年间可持续发展水平的时间动态,并以各省为边界,计算了2015年的区域可持续发展水平差异。计算结果显示:(1)十年间,我国整体上的可持续发展水平在逐步提高,能反映出我国生产率水平的提高和资源利用效率的提高;(2)从要素投入看,自然资源投入仍然占主要,但比例在逐渐降低。环境成本投入比例呈逐步降低趋势,说明环境保护取得了成效。另外,在2010年后,人力资源投入比例增加很快,反映了我国经济发展中劳动力成本上升明显。(3)各省市的计算结果差异较大,在不考虑区域间进出口的情况下,从GDP产出角度,北京的可持续发展水平最高,西藏最低。通过将本文的评价结果与绿色发展指数的评价结果进行比较,发现具有较好的一致性。建立的方法框架是对能值分析方法的扩展和完善,在今后的研究中,还需要继续对该方法框架中没有考虑全面的因素加以考虑,以便于更全面客观地反映区域的可持续发展水平。     

Life Cycle of Titanium Dioxide Nanoparticle Production

Life cycle impact of emissions, energy requirements, and exergetic losses are calculated for a novel process for producing titanium dioxide nanoparticles from an ilmenite feedstock. The Altairnano hydrochloride process analyzed is tailored for the production of nanoscale particles, unlike established commercial processes. The life cycle energy requirements for the production of these particles is compared with that of traditional building materials on a per unit mass basis. The environmental impact assessment and energy analysis results both emphasize the use of nonrenewable fossil fuels in the upstream life cycle. Exergy analysis shows fuel losses to be secondary to material losses, particularly in the mining of ilmenite ore. These analyses are based on the same inventory data. The main contributions of this work are to provide life cycle inventory of a nanomanufacturing process and reveal potential insights from exergy analysis that are not available from other methods.     

Beyond the Food Web Connections to a Deeper Industrial Ecology

Industrial ecology is a school of thought based, in part, upon a simple analogy between industrial systems and ecological systems in terms of their material and energy flows. This article argues for a more sophisticated connection between these diverse systems based on the fact that they are all complex self-organizing systems, operating far from thermodynamic equilibrium. As such, industrial and ecological systems have in common certain constraints and dynamic properties that move beyond the central metaphor of industrial ecology and could align these systems under a more comprehensive analytical framework. If incorporated at a fundamental level, the complex systems framework could add depth and sophistication to the field of industrial ecology.     

Enhancing Life-Cycle Inventories via Reconciliation with the Laws of Thermodynamics

Abstract: Obtaining reliable results from life-cycle assessment studies is often quite difficult because life-cycle inventory (LCI) data are usually erroneous, incomplete, and even physically meaningless. The real data must satisfy the laws of thermodynamics, so the quality of LCI data may be enhanced by adjusting them to satisfy these laws. This is not a new idea, but a formal thermodynamically sound and statistically rigorous approach for accomplishing this task is not yet available. This article proposes such an approach based on methods for data rectification developed in process systems engineering. This approach exploits redundancy in the available data and models and solves a constrained optimization problem to remove random errors and estimate some missing values. The quality of the results and presence of gross errors are determined by statistical tests on the constraints and measurements. The accuracy of the rectified data is strongly dependent on the accuracy and completeness of the available models, which should capture information such as the life-cycle network, stream compositions, and reactions. Such models are often not provided in LCI databases, so the proposed approach tackles many new challenges that are not encountered in process data rectification. An iterative approach is developed that relies on increasingly detailed information about the life-cycle processes from the user. A comprehensive application of the method to the chlor-alkali inventory being compiled by the National Renewable Energy Laboratory demonstrates the benefits and challenges of this approach.     

The use of systems analysis methods in the sustainable management of wetlands

The management of the utilisation of natural resources from wetland ecosystems is a multiobjective and complex task. The creation of innovative decision making tools for sustainable wetland resource utilisation is an important challenge for the future. This is particularly crucial in the light of the growing shortages for high quality freshwater and the vanishing habitat for a large number of wetland fauna and flora species. Because wetlands combine attributes of both aquatic and terrestrial ecosystems, wetlands are often at the crossroads of a number of disciplines with no specific discipline of its own. Therefore, management programmes require a multidisciplinary approach founded on a systematic monitoring of key biological and physical parameters. A European Commission DG XII research project dedicated to the development of management tools for wetland resources in Latin America is being developed by a multidisciplinary team of researchers from eight universities, located in four EU member states, Argentina and Brazil. The study sites that will be utilised for this analysis are two shallow lakes in Northeast Argentina within the large (13000 km²) wetland `Esteros del Ibera'. Continuous and periodic in-situ monitoring instrumentation has been installed in a long term monitoring programme of hydrological and meteorological factors, coupled with monthly biological and ecological data gathering. Potential future scenarios for wetland resource use are being discussed in a series of public meetings with key provincial and local actors (teachers, university professors, clergymen, local business persons and politicians). These meetings address both the small scale modifications of wetland use (water extraction for agriculture, tourism, controlled hunting) as well as regional projects related to the creation of large scale economic development (forestation, modification of nearby waterways for hydroelectric production and increased river transportation). Models are developed relating the chemical, physical, biological and ecological parameters monitored. These models will be dedicated to analysing the effects of development on wetland functions and resource quality. An economic model will be created to evaluate potential modifications in wetland functions in the local and regional socio-economic context. Evaluation instruments are developed and tested which include; qualitative models using loop analysis, goal functions based on the aquatic trophic web and the overall energy flux in the lagoon, and a geographical information system utilising satellite images. The purpose of these instruments is to examine the overall impacts of development alternatives on resource quality and ecosystem integrity, as well as demonstrating key parameters that should be more closely monitored. The final package will include an evaluation of the potential impacts of the development scenarios proposed by the key actors, recommendations to reduce specific impacts through alternative technologies, together with a monitoring programme and analysis tools for improved decision making in wetland resource management.     

与生态系统的演化

１引言美国著名生态学家Ｂ．Ｐ．奥德姆在一篇文章中指出了９０年代生态学的重要观点［１］,其中概念就是“生态系统是一个远离平衡态的热力学开放系统。”可见,热力学理论与生态学理论的相互渗透,已成了当今生态学研究的重要方向。对于复杂系统的演化,已出现多种研究...     

湖泊水库结构生态动态模型

综述了湖泊水库结构生态动态模型的研究进展及其在湖泊水库环境生态模拟中的应用。结果表明,热力学理论为获取湖泊水库生态系统的特性提供了一条整体性的途径,热力学概念“Ｙｏｎｇ”可将生态学理论（达尔文理论）和热力学理论（最大Ｙｏｎｇ原理）很好地联系起来。引入Ｙｏｎｇ后,许多重要模型参数的目标函数可根据最大Ｙｏｎｇ原理获得,达尔文“达者生存”理论可被定量为一个生态约束条件用于发展湖泊水库结构生态结构模型,从     

The shifts in species composition and ecological modelling in hydrobiology

Ecosystems have an enormous flexibility to meet changes in external factors and still maintain their functions. If present species are not able to cope with the conditions, given by the external factors, new species are waiting in the wings ready to take over. It is a serious shortcoming of our present ecological models, that they are not able to describe these changes in species composition. However, it seems that the thermodynamic function exergy may be used as goal function in ecological models to incorporate the flexibility of real ecosystems and the selection of species into our models of ecosystems. The application of exergy in modelling may be considered a translation of Darwin's selection into thermodynamics. The theoretical basis for the application of exergy as goal function is presented, and applications of exergy in ecological models are illustrated by several case studies.     

An Indicator to Evaluate the Thermodynamic Maturity of Industrial Process Units in Industrial Ecology

The article suggests a measure to evaluate the thermodynamic maturity of industrial systems at the level of single process units. The measure can be quantified with reasonable confidence on the basis of entropy production as defined by irreversible thermodynamics theory. It quantifies, for one process unit, the distance between its actual state of operation and its state with minimum entropy production or optimum exergy efficiency, when the two states are constrained with a fixed production capacity of the process unit. We suggest that the minimum entropy production state is a mature state, or that processes that operate at this state are mature. We propose to call the measure "the thermodynamic maturity indicator" (π), and we define it as the ratio between the minimum entropy production and the actual entropy production. We calculated π on the basis of literature data for some examples of industrial process units in the chemical and process industry (i.e., heat exchanger, chemical reactor, distillation column, and paper drying machine). The proposed thermodynamic measure should be of interest for industrial ecology because it emerges from the entropy production rate, a dynamic function that can be optimized and used to understand the thermodynamic limit to improving the exergy efficiency of industrial processes. Although not a tool for replacing one process with another or comparing one technology to another, π may be used to assess actual operation states of single process units in industrial ecology.