Use of Symbiosis Products from Integrated Pulp and Paper and Carbon Steel Mills: Legal Status and Environmental Burdens

This study assesses the policy/legal status of both multistream residues and potential secondary products (“symbiosis products”) and whether there could be environmental benefits associated with the utilization of residues from integrated pulp and paper and carbon steel mills as raw materials for such secondary products. Waste‐related European Union (EU) and Finnish policy and legal instruments were reviewed to identify potential constraints for, and suggested next steps in, the development of potential process industry residue‐based symbiosis products. The products were soil amendment pellets, low‐grade concrete, and mine filler. A global warming potential (GWP) assessment and an exergy analysis were applied to these potential symbiosis products. Some indicative GWP calculations of greenhouse gas emissions associating similar and/or analogous products based on virgin primary raw materials, more energy‐intensive processes, and the alternative treatment of these residues as wastes are also presented. This study addresses GWP, exergy, and legal aspects in a holistic manner to determine the potential environmental benefits of secondary products within the EU legal framework. The GWP assessment and exergy analysis indicate that the utilization of multistream residues causes very low environmental burdens in terms of GWP. The utilization option can have potential environmental benefits in terms of GWP through process replacement and avoided landfilling and waste treatment impacts, as well as potentially through emission reductions from product replacement if suitable and safe applications can be identified. Waste regulation does not define the legal requirements under which utilizing residues in such novel concepts as introduced in this study would be possible, nor how waste status could be removed and product‐based legislation be applied to the potential products instead.     

A thermodynamic theory of microbial growth

Our ability to model the growth of microbes only relies on empirical laws, fundamentally restricting our understanding and predictive capacity in many environmental systems. In particular, the link between energy balances and growth dynamics is still not understood. Here we demonstrate a microbial growth equation relying on an explicit theoretical ground sustained by Boltzmann statistics, thus establishing a relationship between microbial growth rate and available energy. The validity of our equation was then questioned by analyzing the microbial isotopic fractionation phenomenon, which can be viewed as a kinetic consequence of the differences in energy contents of isotopic isomers used for growth. We illustrate how the associated theoretical predictions are actually consistent with recent experimental evidences. Our work links microbial population dynamics to the thermodynamic driving forces of the ecosystem, which opens the door to many biotechnological and ecological developments.     

What Is Resource Consumption and How Can It Be Measured?

When analyzing the metabolism of our economy, the usual choice for a measure of resource consumption is the throughput of matter and energy. This, however, cannot be sufficient, since consumption by definition is always relating to the destruction or transformation, and hence a change in quality, not only in quantity, of material or energy flows. Here, an approach is presented that takes the entropy production associated with any process as a measure for the resource consumption of that process. Entropy production is thereby used to approximate the intuitive notion of consumption, which can best be described by the term loss of potential utility. This article delivers theoretical evidence for the validity of this choice, and a second article in a future issue will present an application taken from the metallurgical sector. The related concept of exergy analysis is discussed and compared against the entropy approach.     

基于生态流方法的土地整治项目对农田生态系统的影响研究

将土地整治活动作为外界对农田生态系统(项目区)集中性的外部激励,以陕西关中凤翔县典型土地整治项目为例,分析了项目实施前后生态流(物质流、能量流、信息流)变化状况,建立了土地整治生态影响概念性模型,明确了相应生态流的流向与路径关系,使用可用能法和能值法测算项目区外部输入及生态产品输出,应用生态流分析法,对土地整治项目生态流和系统效率进行了定量计算。根据设定的土地整治工程使用年限,评估了项目实施后区域净生态价值、自然资源依赖度、可更新资源依赖度、生态产出率、生态承载力和生态可持续度等指标的时间变化过程。得到以下研究结果:(1)可用能法和能值法测算出的系统生态效益均呈现由项目建设初期陡降为负值,而后指数增加,再趋于平稳的过程;(2)可用能法测算出项目实施后的第29年,生态效益由亏转盈,体现出系统从被扰乱后恢复自然平衡状态的过程;(3)能值法测算出项目实施后的第4年,生态系统趋于平衡状态;(4)研究区土地整治项目的经济效益为负,于项目实施3a后趋于平稳,总投资中农业生产年投入占资金总额的78.35%。通过可用能和能值方法的结合,可以定量计算系统稳定性,为土地整治项目的物质、劳动力和资金投资选择等提供借鉴。     

珠海市水岸线生态敏感性评价

水岸线对生态环境保护具有重要作用,但过度及不当的利用已造成部分岸线出现侵蚀甚至破坏,如何合理开发与利用水岸线已成为一个十分关注的问题。鉴于此,本研究以珠海市为研究区,选取水岸线500 m范围内影响水岸线功能的坡度、归一化植被指数、生物多样性保护重要性、距离基本农田距离和距离脆弱生态系统距离为评价指标,进行单因子和综合生态敏感性评价,以缓冲区内最大敏感性等级赋值水岸线的综合生态敏感性,使用叠加排序法识别不同敏感区的主要影响因子,并据此提出不同敏感性岸线的开发利用建议。结果表明:(1)研究区水岸线综合敏感性与岸线缓冲区内各单因子和综合敏感性空间分布类似,整体以不敏感和轻度敏感为主,中度和高度敏感相对较少且多集中在香洲区和斗门区;(2)缓冲区内各单因子在不同变化范围内,不同生态敏感性等级的面积百分比不同:在坡度为25°~45°、归一化指数0.45、生物多样性保护中等重要、距离基本农田距离300~500 m和距离脆弱生态系统距离100 m时,中高度敏感区的面积百分比最大;(3)缓冲区内轻度、中度和高度敏感区的关键影响因子分别为:距离基本农田距离、距离基本农田距离与生物多样性保护重要性、距离脆弱生态系统距离与生物多样性保护重要性;(4)针对高度敏感、中度敏感以及轻度和不敏感岸段,建议分别采取严格控制、限制开发建设以及协调保护的开发利用措施。     

独龙江河流生态系统健康评价

于2018年10—11月,对独龙江水系干流及支流的河流物理生境、水体理化性质和大型底栖动物进行调查,并根据独龙江自身特点,运用改进的河流健康综合评价指数对该地区生态系统健康状况进行了评价。结果表明:该地区调查样点中85.2%的样点处于健康状况,仅人口密集的乡镇附近健康状况处于亚健康水平,其中旅游业发达的独龙江乡健康状况最差。河流是水资源的重要载体,随着当地旅游业的不断发展,科学评价当地河流的健康状况可以为独龙江河流生态系统修复、水资源的合理开发利用及可持续发展提供重要的科学依据。     

城市建筑代谢研究方法及其展望

建筑代谢是当前城市代谢研究领域中的一个新兴热点问题,其研究着重关注建筑系统中物质能量流动可能对周围环境产生的压力及其有害影响。本文在阐明城市建筑代谢内涵的基础上,综述了国内外建筑代谢研究方法的进展情况,分析了目前城市建筑代谢研究方法的适用范围及其特点,指出了城市建筑代谢研究方法在未来应从以下几个方面发展:开发跨城市边界的代谢研究方法;注重建筑代谢中非物质性代谢流研究;制定适合乡土建筑地域特点的代谢研究方法;综合物质量和价值量的建筑代谢研究,全面认识和评价建筑的可持续性。     

The use of structural dynamic models to explain successes and failures of biomanipulation

A development of a structural dynamic model, i.e. a model with current change of the most important parameters according to a goal function, is presented with the aim to explain the structural changes observed in lakes, when the nutrient concentration is increased or decreased. This type of models may be important in lake management as it may be possible qualitatively to predict the success or failure of biomanipulation. The answer to the crucial question: àt which phosphorus level will the success of biomanipulation be most probable?' will probably require the development of model which takes into account site specific processes and properties, i.e., a more complicated model. As goal function is proposed the thermodynamic function, exergy, which is defined as the work content of the system (model) compared with the system at thermodynamic equilibrium. It is shown that the structural dynamic modelling approach has been able to explain the shift from large to small zooplankton species at a certain level of phosphorus concentration, accompanied by a shifts from a dominance of zooplankton, and predatory fish to a system dominated by planktivorous fish and phytoplankton. The shift in zooplankton species cannot be explained by application of catastrophe theoretical models, which have been used to explain the hysteresis reaction. The results show that the shift should be expected at approximately 0.12 mg P l-1 and that a typical hysteresis reaction occurs at this concentration in accordance with the expectations. These results are consistent with many observations but should be interpreted with great caution, as the model is simple and general and don't account for a number of processes which may influence the results significantly in specific lake studies. The structural dynamic approach has previously been used in ten case studies with good agreement with the observations, but more case studies are needed before a general recommendation of the use of this type of models can be given. The results from this study point toward to apply this type of models for lake management where biomanipulation is involved, although it should be recommended to improve the presented general model with introduction of site specific properties for a considered lake study.     

Extending effectiveness to efficiency: Comparing energy and environmental assessment methods for a wet cooling tower

Improving the environmental performance and energy efficiency of cooling towers requires systematic evaluation. However, methodological challenges emerge when applying typical environmental assessment methods to cooling towers. Hence, this paper compares the methods, analyzes their strengths and weaknesses, and proposes adaptions for evaluating cooling towers. As a case study, we applied five methods for assessing the wet cooling system of the high-performance data center in Stuttgart. These are material flow analysis (MFA), life cycle inventory, life cycle assessment (LCA), exergy analysis, and life cycle exergy analysis (LCEA). The comparison highlights that the LCA provides the most comprehensive environmental evaluation of cooling systems by considering several environmental impact dimensions. In the case of the wet cooling tower, however, electricity and water consumption cause more than 97% of the environmental impacts in all considered impact categories. Therefore, MFA containing energy flows suffices in many cases. Using exergy efficiency is controversially debated because exergy destruction is part of the technical principle applied in cooling towers and, therefore, difficult to interpret. The LCEA appears inappropriate because construction and disposal barely affect the exergy balance and are associated with transiting exergy. The method comparison demonstrates the need for further methodological development, such as dynamic extensions or the efficiency definition of cooling towers. The paper highlights that the methodological needs depend on the specific application.